Post by: Jay Cropper on March 09, 2009, 08:52:16 PM
Post by: Tim McCulloch on March 09, 2009, 09:36:48 PM
To start with, Danley doens't make up numbers; next they pay for 3rd party measurement and verification.
The only other manufacturer who's numbers I don't question is Community.
Have fun, good luck.
Tim Mc
Post by: Joe Henson on March 09, 2009, 09:53:10 PM
Post by: Tim Padrick on March 09, 2009, 10:09:51 PM
Post by: Jay Cropper on March 09, 2009, 10:16:22 PM
Post by: Chris Davis on March 09, 2009, 10:39:11 PM
I can imagine this becoming a defacto standard among those of us watching the size and weight of each box.
Post by: Chris Davis on March 09, 2009, 10:45:47 PM
Yeah baby...| Tim Padrick wrote on Mon, 09 March 2009 22:09 |
Check the graph for efficiency. They call it 104. Some manufacturers would have claimed 107, 109, or even 112 from the same box. |
Post by: Stephen G Robertson on March 09, 2009, 10:54:35 PM
I am writing to let you know of a huge deficiency in your product line. I am the happy owner of a pair of a pair of TH-115 and they rock. But 2 years ago when I needed a high output speaker on a stick, Danley offered no such product so I bought Nexo PS15's. Two years have passed and 8 or 10 very interesting products have been released. But no 90x50 HIGH OUTPUT (130dB+), 80 pound or less, Speaker on a stick. The SH-95 comes close, but not quite. I know your market is install but really, if you build it they will come. For every SH96 or SH25 you sell. You could sell 100 of the box I propose. Oh and the new sub looks cool, do the casters go on the front of the box?
Your Friend,
Steve
Post by: Ivan Beaver on March 09, 2009, 11:08:15 PM
) or made out of carbon fiber and be really expensive 
.It is not just about making a box that has a particular weight/output. It is also about making it SOUND good, not just throwing out "another box" that will make a loud noise-there are plenty of those out there.
There are more things "in the works".
Yes- on the portable version of the TH212, the castors go on the front of the cabinet-on the slanted board. Yes it is an odd place to put them, but there was no place else to go-without altering the performance (choking off the horn)-or making the cabinet larger.
Post by: Matt Harris on March 09, 2009, 11:58:59 PM
Post by: Stephen G Robertson on March 09, 2009, 11:59:11 PM
| Ivan Beaver wrote on Mon, 09 March 2009 22:08 |
There are some serious limitations on what products can actually do-for a given weight/coverage etc. Yes the boxes could be made out of plastic (and sound like it ) or made out of carbon fiber and be really expensive .It is not just about making a box that has a particular weight/output. It is also about making it SOUND good, not just throwing out "another box" that will make a loud noise-there are plenty of those out there. |
Really, it is about weight and output.
Most all of your top boxes put SQ as their most important design critera, size and weight be damned. I totally respect that. I would use a pair of SH96 if I could. But its not remotely feasible. It does not matter how good it sounds if i can't use it. So I buy from the other guy, and those Nexo's sound great. If they can do it so can you.
Really, I'm not trying to be a jerk here, Just a little constructive criticism from an otherwise delighted customer.
Post by: Mike Pyle on March 10, 2009, 12:04:22 AM
| Ivan Beaver wrote on Mon, 09 March 2009 20:08 |
Yes- on the portable version of the TH212, the castors go on the front of the cabinet-on the slanted board. Yes it is an odd place to put them, but there was no place else to go-without altering the performance (choking off the horn)-or making the cabinet larger. |
Where will the handles be? Is there a mudflap option? j/k
Post by: Tony "T" Tissot on March 10, 2009, 12:22:50 AM
Or did M. C. Escher make the photograph?
Post by: Pascal Pincosy on March 10, 2009, 12:27:13 AM
| Ivan Beaver wrote on Mon, 09 March 2009 20:08 |
Yes- on the portable version of the TH212, the castors go on the front of the cabinet-on the slanted board. Yes it is an odd place to put them, but there was no place else to go-without altering the performance (choking off the horn)-or making the cabinet larger. |
You guys might want to re-think this. There is no way in hell that I'm aiming a set of wheels at my audience. I'm looking for speakers that look cool, not speakers that look like they came out of someone's garage. Please no wheels, cables, or connectors on the fronts of the speaker guys. Maybe we could get the wheels mounted on the back or something?
Post by: Matt Harris on March 10, 2009, 01:48:41 AM
Post by: HarryBrillJr. on March 10, 2009, 02:24:33 AM
| Matt Harris wrote on Tue, 10 March 2009 00:48 |
I don't want the people who drink too much and pass out on the dance floor to have to stare at those wheels |
I laughed so hard I started to cough. Nearly woke my wife up too.
I think they are tilt back wheels. I've never been fond of them because they are awkward and once in position in front of the stage you have to work them out. In this case they seem like they would be easy to put into and pull out of position because the wheels are on the front.
Post by: Pascal Pincosy on March 10, 2009, 02:34:33 AM
Post by: Ivan Beaver on March 10, 2009, 08:34:45 AM
| Matt Harris wrote on Mon, 09 March 2009 23:58 |
No phase trace for the specs? |
When that was measured the wind was blowing pretty good. You can forget about phase response with the wind blowing.
BTW who else shows phase traces on their products?
Post by: Michael Hedden Jr. on March 10, 2009, 08:38:09 AM
[/quote]Your comments are very much appreciated and as Ivan has already stated, several things are in the works and fact is we will bring close to a dozen new products to INFOCOMM due to customer requests.
Mike Hedden
Danley Sound Labs, Inc.
PS
Last week we had our first demo of a Genesis Horn array for tops and the Matterhorn for subs! There's full range with headroom for you.
Post by: Ivan Beaver on March 10, 2009, 08:51:25 AM
Yeah I don't like the wheels on the front either, but in trying to keep the package as small as possible (it over 20% smaller than a TH115), that was the only place. Yes a caster plate could have been used-but that would drive up the cost and have one more thing to have to deal with at the gig.
It is all a matter of compromise.
But HEY-it is distinctive
There are actually 2 operating "modes". One is with the cabinet laying on it's large side, the sound "exit" is on the narrow side-15" tall. This is for ground stacking. There are interlocking skids on the portable version.
If you want a LOT more forward directivity then you can swap the exit panel and another panel on the side to where the sound comes out in a corner of the large side.
You can take 4 of these and put them in a square with the mouths all in the middle and you will gain quite a bit of forward directivity (ie cardioid action-so to speak). This will increase the level out front and reduce it in the rear. You have 180
Post by: Paul Drenth on March 10, 2009, 09:29:41 AM
| Pascal Pincosy wrote on Mon, 09 March 2009 23:27 | ||
You guys might want to re-think this. There is no way in hell that I'm aiming a set of wheels at my audience. I'm looking for speakers that look cool, not speakers that look like they came out of someone's garage. Please no wheels, cables, or connectors on the fronts of the speaker guys. Maybe we could get the wheels mounted on the back or something? |
What about a caster plate/base? Seems easy enough.
Otherwise, I'm pretty pumped about this new "portable" sub. I never thought I'd hear portable and Danley in the same sentence.
I stand corrected. 
Paul
Post by: jason misterka on March 10, 2009, 10:04:05 AM
I can probably speak for everyone in attendance when I say they stole the show. It would have been nice the hear them with a drum kit instead of a mastered CD, and it would have been nice if they had a bigger amp to try them out on, but we all were really impressed. And we were mostly regional providers used to high Q very loud touring boxes.
That said, they are difficult to move even with the "touring" wheels, especially down a curb and up a truck ramp. Once they are on a flat stage, it was fine, but until then...
If - hopefully, when
- we buy some, I was thinking of putting two side by side on a single caster plate of some sort, assuming that it could be designed to fit a truck ramp. Maybe they could come up with something smart at the factory.Otherwise at the demo, the Genesis is pretty cool, and gives you some neat options for installations. With the right budget, a pair center hung could be just the ticket for a lot of HOW or theatrical installations with a balcony.
Jason
Post by: john nelson on March 10, 2009, 10:26:54 AM
Post by: Michael Hedden Jr. on March 10, 2009, 11:25:14 AM
Jason[/quote]
Jason,
Thanks for the kind words. The install version doesn't have wheels so it would be easy for us to have a tour model that has no wheels and a caster plate option. It is an easy fix, we just want to give folks options so for the small regional, perhaps the wheels attached make sense, for the bigger folks, caster plates. The TH812 and TH221 both make use of a very heavy duty caster plate.
Thanks,
Mike Hedden
Danley Sound Labs, Inc.
Post by: HarryBrillJr. on March 10, 2009, 11:27:36 AM
| john nelson wrote on Tue, 10 March 2009 09:26 |
15" x 36' x 36" does not strike me as a very good set of dimensions for a truck pack but the specs do look good. |
in a 96" or 90" truck you could pack 6 across and stick 6 more on top. 12 subs in 3ft of depth.
Post by: Scott Raymond on March 10, 2009, 02:30:35 PM
| Michael Hedden Jr. wrote on Tue, 10 March 2009 07:38 |
PS Last week we had our first demo of a Genesis Horn array for tops and the Matterhorn for subs! There's full range with headroom for you. |
Hmmm....Just add a hydralic fold up tower on the roof (Matterhorn) and a fold down deck for the back for a 30 min PA. Back one up on each side of the stage, roll the Genesis (or whatever) out and hoist away.
P.S. Ever thought of offering the Matterhorn as a kit to save on shipping costs (buy the box locally) for die-hard builders?
Post by: Michael Hedden Jr. on March 10, 2009, 02:49:58 PM
Well we have had several requests for a pole cup mounted box
Come to think of it, center of gravity issues would certainly be minimized.Mike Hedden
Danley Sound Labs, Inc.
Post by: Franz Francis on March 10, 2009, 03:48:53 PM
During the February Carnival Festival season I deployed twenty TH-115 with our Nexo rig,the results was just unbelievable .
Probably the Danley guys would not recommend arraying the subs this way but I discovered there is huge amount of forward directivity in this configuration.
Franz
Post by: Michael Hedden Jr. on March 10, 2009, 04:09:20 PM
Franz,
I have sttached the TEF measurements of an array of four on top of four just like you've got shown that I measured a couple of years ago. The actual measured NOT calculated response is -6dB 90 degrees off axis @40Hz and more attenuation as you go up in frequency. Directly behind the array is over -20dB down @40Hz as well. Bottom line, the technique works ridiculously well.
Thanks,
Mike Hedden
Danley Sound Labs, Inc.
Post by: HarryBrillJr. on March 10, 2009, 05:38:08 PM
This is one of the main reason I like to have a (seemingly) ridiculous qty of subs.
Post by: Ivan Beaver on March 10, 2009, 06:38:49 PM
| Scott Raymond (Scott R) wrote on Tue, 10 March 2009 14:30 |
P.S. Ever thought of offering the Matterhorn as a kit to save on shipping costs (buy the box locally) for die-hard builders? |
It WAS a kit.
A real DIY project. It took 2 months out of my life and truly wore me (and others) out. There is so much stuff inside it, it would take a container that size just to ship the guts, so why not just ship the container with it?
Post by: Ivan Beaver on March 10, 2009, 06:48:17 PM
| HarryBrillJr. wrote on Tue, 10 March 2009 17:38 |
That kind of directivity lends itself well to the left/right sub configuration because power alley, although not eliminated is drastically reduced, and the affect is limited to a smaller pie slice either side of the middle. This is one of the main reason I like to have a (seemingly) ridiculous qty of subs. |
Having a good physical boundary can be a really good thing for subs (hence the old "barn doors"). The ancients keep stealing our inventions
.That is part of the design for the TH812. With just 2 of them, you have 16-12" drivers all grouped together in the middle and a 10' wide wall x 5' tall.
Post by: Stephen G Robertson on March 10, 2009, 06:51:44 PM
Post by: Pascal Pincosy on March 10, 2009, 06:54:55 PM
| Franz Francis wrote on Tue, 10 March 2009 12:48 |
This is a little off topic note I am not trying to divert the present topic, but it is related to the Sub thread of topic indirectly. During the February Carnival Festival season I deployed twenty TH-115 with our Nexo rig,the results was just undeliverable. Probably the Danley guys would not recommend arraying the subs this way but I discovered there is huge amount of forward directivity in this configuration. |
I've also done this configuration with the TH-115's and I'd have to say that in big stacks its my favorite. You just have to be careful stacking them as the skids on the cabinet bottoms make it a bit precarious. I used some thin ply between the cabinets as shims and it made it all better.
Post by: Stephen G Robertson on March 10, 2009, 07:07:00 PM
| Ivan Beaver wrote on Tue, 10 March 2009 17:48 | ||
Having a good physical boundary can be a really good thing for subs (hence the old "barn doors"). The ancients keep stealing our inventions .That is part of the design for the TH812. With just 2 of them, you have 16-12" drivers all grouped together in the middle and a 10' wide wall x 5' tall. |
Does it have an exit in the short dimension so you can put it under a stage, or use it as the stage
Post by: Ivan Beaver on March 10, 2009, 07:28:25 PM
| Stephen G Robertson wrote on Tue, 10 March 2009 19:07 | ||||
Does it have an exit in the short dimension so you can put it under a stage, or use it as the stage |
It would not fit under a stage-unless it is a 6' tall stage.
The TH221 will go under a stage-assuming you have 5x5' open on the ground. When it is laying down it is 28" tall.
Post by: Douglas R. Allen on March 10, 2009, 08:29:11 PM
Thanks
Douglas R. Allen
Post by: Eytan Gidron on March 11, 2009, 03:56:31 AM
TH221 and TH812? I couldn't find these on the Danley website, do you have links, photos, PDFs etc?
Post by: Michael Hedden Jr. on March 11, 2009, 07:35:39 AM
| Eytan Gidron wrote on Wed, 11 March 2009 07:56 |
Hi Ivan, TH221 and TH812? I couldn't find these on the Danley website, do you have links, photos, PDFs etc? |
Eytan,
We have been blessed with an abundance of work including Karl Peterman's LCR auditorium project and a stadium project that Ivan and I will be tuning this week comprised of over 400 cabinets. Several miles will be logged on the old legs this week!
Predicated on weather cooperating so we can get outside, the information for both models will be up on the site within a week or so. I spent an hour or so last night listening to the new subs. These are going to be bringing a lot of smiles and head turns to a lot of people.
Mike Hedden
Danley Sound Labs, Inc.
Post by: Steve Anderson on March 25, 2009, 12:01:47 AM
| Michael Hedden Jr. wrote on Wed, 11 March 2009 22:35 |
the information for both models will be up on the site within a week or so. |
it's been 2 weeks now, enquiring (and impatient) minds want to know
Post by: Ivan Beaver on March 25, 2009, 04:57:21 PM
| Steve Anderson wrote on Wed, 25 March 2009 00:01 | ||
Re: 812 and 221...
it's been 2 weeks now, enquiring (and impatient) minds want to know |
Here are the measured responses. They are a little tough to read, but that is the way TEF pastes screen shots
The curser line is 110dB.
These are each single cabinets measured outdoors at a distance of 10M and 28.3V input-so the same relative level as 2.83V @ 1M, but the long distance removes any artificial gains that would be seen by measuring up close to a cabinet.
Post by: Art Welter on March 25, 2009, 05:05:22 PM
Nice LF response!
What are the size, weight, nominal impedance and driver compliment of the TH812 and TH221?
Art Welter
Post by: Caleb Dick on March 25, 2009, 05:11:30 PM
I'm curious about cost, power requirements, relative 'impact' compared to TH-115 and TH-212, and if they are flyable. Looks like my love for lots of deep bass are being met with the 221!
Caleb
Post by: Phil Lewandowski on March 25, 2009, 05:14:07 PM
| Ivan Beaver wrote on Wed, 25 March 2009 16:57 | ||||
Here are the measured responses. They are a little tough to read, but that is the way TEF pastes screen shots The curser line is 110dB. These are each single cabinets measured outdoors at a distance of 10M and 28.3V input-so the same relative level as 2.83V @ 1M, but the long distance removes any artificial gains that would be seen by measuring up close to a cabinet. |
Wow!!
May I ask Ivan, what is the size and weight of the TH-221? That could be an awesome "real" sub!
{edit} Sorry, was informed that the size was in an earlier post. So I guess the weight question is still up.
Thanks!
Phil
Post by: Ivan Beaver on March 25, 2009, 07:08:53 PM
| Caleb Dick wrote on Wed, 25 March 2009 17:11 |
Assuming the 812 has 8x 12", and the 221 has 2x 21" |
You are right on the driver count. They are both the same size. They have removable castor boards and are easily rolled by one person and 2 people can put them into position and can stack the 221 2 high.
Typical 2 812's would be 10' wide x 5' high with all 16 12" drivers right in the middle. The 10' wide "array" will provide lots of forward directivity.
2 221's would be 60" wide and 56" tall.
They are 60x60x28 and are completely different physical layouts-intended for different applications/layouts.
The 812 is 5,600WRMS, (11,200 peak) and can be wired for a single 4 ohm or 2 8 ohm loads via internal jumper. It can be wired as a single 16 ohm load but I doubt anybody would use it that way.
The 221 is 3,000WRMS (6,000 peak) and can wired for a single 2 ohm load-2 4 ohm loads or a single 8 ohm load.
I am not sure of the weight, but if you hit stairs you are screwed
No fly points as yet-as they are intended as a ground stack-but could be ordered as an option if desired.
They cost more than a TH115
Sorry for the photo quality
Post by: Caleb Dick on March 25, 2009, 07:33:59 PM
How does pricing compare to two TH-115's?
Caleb
Post by: Jon Waller on March 25, 2009, 07:39:03 PM
Post by: Art Welter on March 25, 2009, 07:39:52 PM
The 812 is like a B-DEAP maxi!
Wayne P. will love the fact it’s push pull, too.
So was the posted TH812 response 28.3 volts into 4 ohm?
That would be 200 watts, rather than 100, so the sensitivity would be “only” 105 at 30 HZ or so.
The TH221,28.3 volts at 2 ohm or 8 OHM? If 8, it looks to be the clear winner on paper, but damn that's a deep cabinet. Can’t put that in front of the fire curtain.
Which wins the subjective punch test?
Art Welter
Post by: Ivan Beaver on March 25, 2009, 08:11:58 PM
| Caleb Dick wrote on Wed, 25 March 2009 19:33 |
On the 221, is that 3k watts RMS total for the cab at 2 or 8 ohms? So, 6k watts 'program', also peak; or 12k watts peak? Recommended amp power 6k watts for rock per cabinet? How does pricing compare to two TH-115's? Caleb |
The 221 has 2 1500WRMS drivers-so it is the same "wattage" at any of the impedances.
Danley does not like to play the "peak" game in which you just "automatically" add 3dB to the program power
. But if you want to compare to other cabinets I guess you could say that.But then the 812 would be 22,400 watts
Both cabinets cost more than a couple of TH115s. Call the office for pricing.
I like to recommend power to be between 1 and 1.5 times the RMS rating. But I am conservative when playing the ratings game. I think gear should be rated for what it can actually do-but then that is the bench tech in me coming out
Post by: Ivan Beaver on March 25, 2009, 08:16:35 PM
| Jon Waller wrote on Wed, 25 March 2009 19:39 |
I would think the 812 could be wired as two, 2 ohms loads of 2800Wrms each. |
That would be an option, but would require a rewiring of the drivers. There are 2 sets that are wired in a series/parallel combination. In the current configuration, you just move two jumpers behind the jack plate to select the different impedances.
The idea was to take 2 of the Danley 6.5K amps and mono bridge into each cabinet. That way the amps are seeing a nice easy 8 ohm load (4 ohms per side because of bridging) and you have available right at twice the RMS rating for power.
I am sure you could order the wiring any way you want.
Post by: Ivan Beaver on March 25, 2009, 08:48:33 PM
| Art Welter wrote on Wed, 25 March 2009 19:39 |
Ivan, The 812 is like a B-DEAP maxi! Wayne P. will love the fact it’s push pull, too. So was the posted TH812 response 28.3 volts into 4 ohm? That would be 200 watts, rather than 100, so the sensitivity would be “only” 105 at 30 HZ or so. The TH221,28.3 volts at 2 ohm or 8 OHM? If 8, it looks to be the clear winner on paper, but damn that's a deep cabinet. Can’t put that in front of the fire curtain. Which wins the subjective punch test? Art Welter |
While it looks like a push pull, that was not the intended design-just like the TH212. The horn loading on the different drivers is different, which is part of the reason the response is so flat, Tom was trying to smooth it out.
The drivers ended up that way-because as Tom puts it "That was a convenient place to put the drivers"
. Yes Wayne would be happy to "think" he had an influence on Tom's design To bad he would be wrong-once again.Who has the biggest and baddest now?
Danley rates all the cabinets sentivities in drive voltage-NOT wattage. Because the impedance varies with freq, an impedance graph is published to let the user determine what impedance they think the cabinet should be rated at for their particular application.
Because it shows what can be expected from a particular input. You cannot "input" watts into a cabinet-watts are the RESULT of a particular drive voltage and particular impedance-but you know that.
Some cabinets are easier to get a meaningful single number than others.
So "if" you were to use a single impedance number, then the 812 would be a 4 ohm load as measured and the 221 would be a 2 ohm load as measured.
But-for example if you look at the impedance plots (to be published with the full spec sheets shortly), you will see on the TH221 an impedance peak at 65hz of 12.5 ohms (when the drivers are in parallel), so that relates to 0.64watts when referenced to 2.83V.
The TH812 has an impedance peak at 39Hz of 18.2 ohms that relates to 0.44 watts when referenced to 2.83V and a 4 ohm wiring.
You notice I took the impedance peaks in the intended freq range of the cabinet not something way out of that-in which they are actually a higher impedance. Just trying to "keep it real".
So exactly what is the impedance? An average across the intended freq band? Or the minimum that it reaches at any one point? What if you don't have many notes at that impedance? Is that actually putting a heavy load on the amp?
That is why just the drive voltage is given.
I have not listened to them side by side, but the TH221 is a VERY tight sounding cabinet-due to the loading and control the Tapped Horn puts on the drivers. It has lots of punch and is truly FUN to be around-even if not driven hard. Not a sloppy-fluffy sounding sub at all.
Post by: Art Welter on March 25, 2009, 09:25:17 PM
I’m happy with specific drive voltage, but one does of course need to know the cabinet minimum impedance so as not to hang too many cabinets on an amplifier.
What is the minimum impedance on the 812 when wired as 4 ohm nominal, and the 221 when wired as 2 ohm nominal?
Art Welter
Post by: Michael Hedden Jr. on March 25, 2009, 10:39:51 PM
Mike Hedden
Danley Sound Labs,Inc.
Post by: Ivan Beaver on March 26, 2009, 06:54:00 AM
| Art Welter wrote on Wed, 25 March 2009 21:25 |
Ivan, I’m happy with specific drive voltage, but one does of course need to know the cabinet minimum impedance so as not to hang too many cabinets on an amplifier. What is the minimum impedance on the 812 when wired as 4 ohm nominal, and the 221 when wired as 2 ohm nominal? Art Welter |
Attached are the impedance plots with 2.8Hz resolution. If Danely used less resolution the dips (and peaks) would not be so extreme-ie smoother, but in the intrest of highly accurate data, a small resolution was used.
The TH812 minimum is 3.5 ohms and the TH221 is 2 ohms (except for that little dip at 20Hz-so maybe that cabinet needs to be remeasured down to 10Hz-and maybe a little bit more resolution.
But the average across the band is higher-so it is up to the user to determine what is the best way to load their amps-and of course that includes the actual amp-series resistance in the loudspeaker cables and so forth.
So the actual load on the amp will vary with different users.
Post by: Charlie Zureki on March 26, 2009, 07:39:22 AM
| Stephen G Robertson wrote on Tue, 10 March 2009 17:51 |
I understand the Matterhorn was built for the military. So I'm wondering why you guys still have it? Did you guys build more than one or is all of that top secret? |
Shhhh..... Military and Top Secret go together...
Hammer
Post by: Michael Hedden Jr. on March 26, 2009, 08:59:35 AM
| Stephen G Robertson wrote on Tue, 10 March 2009 22:51 |
Did you guys build more than one or is all of that top secret? |
Yes
Mike Hedden
Danley Sound Labs, Inc.
Post by: Michael Hedden Jr. on March 26, 2009, 09:08:17 AM
Caleb[/quote]
Pricing of these new subs is more than the pair of 115's but way less than these $15-20k "ultimate" subs from other manufacturers.
Using Danley products as a comparison, a single 812 has the acoustic output and frequency response of four TH215's and is less money, a single 221 has more acoustic output and similar frequency response than four TH50's and is also less money.
Mike Hedden
Danley Sound Labs, Inc.
Post by: John Roberts {JR} on March 26, 2009, 10:30:17 AM
| Ivan Beaver wrote on Thu, 26 March 2009 05:54 |
Attached are the impedance plots with 2.8Hz resolution. If Danely used less resolution the dips (and peaks) would not be so extreme-ie smoother, but in the intrest of highly accurate data, a small resolution was used. The TH812 minimum is 3.5 ohms and the TH221 is 2 ohms (except for that little dip at 20Hz-so maybe that cabinet needs to be remeasured down to 10Hz-and maybe a little bit more resolution. But the average across the band is higher-so it is up to the user to determine what is the best way to load their amps-and of course that includes the actual amp-series resistance in the loudspeaker cables and so forth. So the actual load on the amp will vary with different users. |
As an old amplifier product manager I feel compelled to point out that the "4 ohm" box spends a significant time below 4 Ohms, so if run in parallel will be significantly below 2 ohms. The 2 ohm box is right on, if we ignore the very low end. This LF dip demonstrate the value of carefully setting a LF HPF skirt to keep infrasonic energy out of the audio, which will mainly heat up the drivers and amps for little or no sonic benefit.
JR
PS: amp designers have been long aware of this fudge in nominal impedance, and this is certainly not a bad offender. I've seen some studio monitors with passive crossovers that were real amp killers.... Nominal 8 ohm boxes with <2 ohm dips.
2 Ohm min amps will generally do better than that, but it's not good practice to make ASSumptions about how much extra the designer over-engineered into the amplifier. YMMV
Post by: Langston Holland on March 26, 2009, 11:00:47 AM
Edit: might be better to use a single PL380 per sub in dual 4 ohm mode. TBA...
Post by: Charlie Hughes on March 26, 2009, 01:30:37 PM
| John Roberts {JR} wrote on Thu, 26 March 2009 10:30 |
As an old amplifier product manager I feel compelled to point out that the "4 ohm" box spends a significant time below 4 Ohms, so if run in parallel will be significantly below 2 ohms. |
I don't see this. The graph appears to show that Zmin is 3.5 ohms just as Ivan indicated. This is within the 80% limit for a 4 ohm rated impedance specified by the IEC 60268 standard for loudspeakers.
Post by: Michael Hedden Jr. on March 26, 2009, 02:08:27 PM
| Quote: |
As an old amplifier product manager I feel compelled to point out that the "4 ohm" box spends a significant time below 4 Ohms, so if run in parallel will be significantly below 2 ohms. JR |
John,
Your points are well recieved and very valid. This is why we have the option of powering each driver seperately. Wouldn't it be nice if more manufacturers participated in showing brutally honest data so you could have these discussions?
Mike Hedden
Danley Sound Labs, Inc.
Post by: John Roberts {JR} on March 26, 2009, 02:47:12 PM
| Charlie Hughes wrote on Thu, 26 March 2009 12:30 | ||
I don't see this. The graph appears to show that Zmin is 3.5 ohms just as Ivan indicated. This is within the 80% limit for a 4 ohm rated impedance specified by the IEC 60268 standard for loudspeakers. |
Hi Charlie:
I'll take you word for the IEC spec since the only data I found on google was how many hundreds a copy would cost me.
My point was that 3.5 Ohm measured, when two are paralleled is 1.75 ohm actual. If IEC is fine with speakers dipping 20% low, that makes the 2 ohm nominal 1.6 ohms worst case while still IEC legal..
As I said, amp makers are well aware of this popular practice. Even at Peavey I studied Peavey's popular loudspeaker impedance plots and found many of them dipped well below nominal in low-mid range where a lot of musical energy was present. They was no doubt a bit of gamesmanship to sound a little louder than the next guy at POS. My job at Peavey was to play nice with Peavey speakers so we did. While Mr O'Neil did have to revisit at least one crossover i recall (perhaps before your time there). I guess my broader concern is how 2 ohms has become as commonplace today as 4 ohms was for amp loading.
You probably have a better feel than I do for production variations in such things. I don't know if this is anything more than coincidence, I vaguely recall 3.2 ohm nominal speakers in cars and old radios 3.2 ohms would just fit in that 20% window under 4 ohms.
I appreciate the mindset that the average impedance over the bandpass of interest is higher than nominal even with these dips. For amplifier heating the average impedance is actually more representative. My concern is for current limiting which is very much a peak phenomenon. I don't doubt that some sound quality complaints could be from spurious current limiting only occurring when certain notes fall on impedance minima. If DDT or some overall limiting is working from current limiting this will affect the entire signal.
I meant this more as an object lesson to boys and girls for how they configure their amplifiers in systems. As I said in my post I don't feel TD is a bad offender. He is probably better than many, and probably where he need to be to be competitive.
JR
Post by: John Roberts {JR} on March 26, 2009, 03:23:51 PM
| Michael Hedden Jr. wrote on Thu, 26 March 2009 13:08 |
John, Your points are well recieved and very valid. This is why we have the option of powering each driver seperately. Wouldn't it be nice if more manufacturers participated in showing brutally honest data so you could have these discussions? Mike Hedden Danley Sound Labs, Inc. |
FWIW I am a long time member of the TD fan club and didn't intend this as criticism as much as an attempt to discourage folks from overloading amps.
I find the 2 ohm nominal box design smart.. and except for the drop off at the very bottom it satisfies even the (apparently too strict) JR nominal impedance target. Even there I can't imagine how to make the box any better, but I would advise customers to HPF extreme lows.
I expect any cabinet sold today will get paralleled down to 2 ohms. Experienced amp designers and experienced speaker designers are well aware of this dance, as it isn't anything new. IMO the willingness to run even value amps down at 2 ohms is a fairly recent development.
The 380 plot elsewhere in this thread shows output curves all the way down to 1 ohm, and well designed amps will work down to a short circuit, but it's also worth noting that even that monster amp limits at < 2kW at that 1 ohm, while delivering 2x that power into 2 ohms (apparently output current limited).
Running two of the 812s on that same 380 looks like it's just on the edge of folding back at 1.75 Ohms but very close to the same power as 4 Ohms so probably usable. Any current limiting that occurs that close to clipping will IMO not be audibly significant.
It's nice being able to play "connect the plots" with Ivan's and QSC's data... Results may vary with other amps but that QSC is a solid amp and one of the few that presents the data that clearly.
JR
(no longer an amp guy but I did sleep in a holiday inn once)
Post by: Jeff Knorr - Cobra Sound on March 26, 2009, 04:30:47 PM
| Michael Hedden Jr. wrote on Thu, 26 March 2009 09:08 |
How does pricing compare to two TH-115's? Caleb |
Pricing of these new subs is more than the pair of 115's but way less than these $15-20k "ultimate" subs from other manufacturers.
Using Danley products as a comparison, a single 812 has the acoustic output and frequency response of four TH215's and is less money, a single 221 has more acoustic output and similar frequency response than four TH50's and is also less money.
Mike Hedden
Danley Sound Labs, Inc.[/quote]
Hi Mike,
In the same line of thought as Caleb, how do the new subs (assume singles on the TH812 and TH221 and a block of four TH212's) compare to a block of four TH115's?
I'm interested specifically in overall output, total weight, and efficiency. Obviously the new models go deeper than the TH115's but how about higher up (say above 35-40Hz) do they compare?
Thank you,
Jeff "Needs a demo with the refrigerator sized subs!" Knorr
Post by: Mac Kerr on March 26, 2009, 04:34:38 PM
| Michael Hedden Jr. wrote on Thu, 26 March 2009 14:08 | ||
John, Your points are well recieved and very valid. This is why we have the option of powering each driver seperately. Wouldn't it be nice if more manufacturers participated in showing brutally honest data so you could have these discussions? Mike Hedden Danley Sound Labs, Inc. |
Hey Mike, don't wrench your shoulder patting yourself on the back.
Mac
Post by: Grant Conklin on March 26, 2009, 04:45:31 PM
| Mac Kerr wrote on Thu, 26 March 2009 15:34 | ||||
Hey Mike, don't wrench your shoulder patting yourself on the back. Mac |
Mac-
I understand why you have at times needed to calm the enthusiasm Danley folks have for their product on this forum, but I don't understand this particular remark. I for one do think it would be nice if we could trust the specs of other manufacturers - if they would print the kinds of independently derived data that Danley prints, and serve to educate rather than placate. I think manufacturers need to be encouraged to raise the standard in this regard, and Danley is helping, even if they do toot their own horn along the way.
Thanks,
Grant
Post by: John Roberts {JR} on March 26, 2009, 05:20:10 PM
| Grant Conklin wrote on Thu, 26 March 2009 15:45 |
Mac- I understand why you have at times needed to calm the enthusiasm Danley folks have for their product on this forum, but I don't understand this particular remark. I for one do think it would be nice if we could trust the specs of other manufacturers - if they would print the kinds of independently derived data that Danley prints, and serve to educate rather than placate. I think manufacturers need to be encouraged to raise the standard in this regard, and Danley is helping, even if they do toot their own horn along the way. Thanks, Grant |
I feel a little like that liberal cable guy who said something critical about Obama, and got jumped on by mainstream media. I have nothing but respect for Charlie and TD.
I have seen plenty of data curves from other manufacturer's so Danley is not alone in providing data, saying that theirs is brutally honest implies that others are not (honest).
For the record I don't think I ever met one single speaker engineer who was willing to concede that another company's data might be honest. "Everybody's a liar... but me".
After a while this too becomes background noise.Time for a group hug with all the we love Danley fan boyz.
Mac's job is to keep posters in line and Mike has been known to dance on top of the fine line of propriety in his enthusiasm. I factored that in, and thought Mac's comment was "brutally honest".
JR
Post by: Charlie Hughes on March 26, 2009, 06:23:59 PM
I didn't mean to jump on you. I apologize if my post seemed to do this. My intent was to point out that within industry accepted practices and standards, Danley's decision to rate this loudspeaker at 4 ohms is justified. I have the utmost respect for you as well.
Your points are well taken. It is common for loudspeaker designers to lower the impedance of drivers, primarily woofers, in order to maximize the SPL with a given input voltage while keeping the Zmin high enough to meet the required rated Z. Some manufacturers take it too low, as I suspect this is the point to which you were alluding.
If I'm in a situation where this is necessary to meet target SPL requirements, I shoot for a target Zmin that is a bit higher than the absolute minimum allowed to still justify a given rated Z. This will allow for production tolerances so that no units will have a lower Zmin than allowed.
I suspect that you may be correct; if a note from a very monotonic instrument coincideds with a loudspeaker’s Zmin the amplifier driving the loudspeaker may current limit when driven hard enough.
Post by: Ivan Beaver on March 26, 2009, 06:53:47 PM
, here is the same impedance graph-smoothed and a cursor at 4 ohms.I would argue that the cabinet (across its intended freq band) spends more time (freq wise) at a lot higher impedance than it does below 4 ohm.
So it really does come down to how a particular graph is presented and interpreted.
Post by: Art Welter on March 26, 2009, 07:22:16 PM
I would agree with you that the cabinet (across its intended freq band) spends more time (freq wise) at a lot higher impedance than it does below 4 ohm.
The previous impedance plot makes it look like it drops to 2.5 ohms.
If I had my ‘druthers I’d like to see 5 ohms where the 15 is on the “smoothed” scale, and 10 ohms where 30 is, so the “action” could be easily seen.
I really don’t care where the impedance goes above nominal as long as the frequency response is flat, but knowing where and how far it dips below nominal is useful information for amp choice.
Art Welter
Post by: Ivan Beaver on March 26, 2009, 07:57:04 PM
| Art Welter wrote on Thu, 26 March 2009 19:22 |
Ivan, I would agree with you that the cabinet (across its intended freq band) spends more time (freq wise) at a lot higher impedance than it does below 4 ohm. The previous impedance plot makes it look like it drops to 2.5 ohms. If I had my ‘druthers I’d like to see 5 ohms where the 15 is on the “smoothed” scale, and 10 ohms where 30 is, so the “action” could be easily seen. Art Welter |
The reason it "looks" like it dropped to 2.5 ohms is that the bottom line of the scale was 2 ohms (instead of 0)-and it was not labeled as such.
I don't normally look at the scale of the impedance plot, but rather use the curser as a "dividing line".
Good catch and something to look out for.
This is the same exact smoothed plot, but with a different scale that goes to "0" and only to 20.
Post by: Art Welter on March 26, 2009, 08:28:03 PM
Post by: Ivan Beaver on March 26, 2009, 08:31:27 PM
| Art Welter wrote on Thu, 26 March 2009 20:28 |
Yeah, that’s the chart I want, but without the “finger on the pen”! |
?? Maybe I don't get it-but what do you mean by "finger on the pen"?
Post by: Charlie Hughes on March 26, 2009, 08:49:44 PM
Post by: Ivan Beaver on March 26, 2009, 09:07:40 PM
| Charlie Hughes wrote on Thu, 26 March 2009 20:49 |
A finger on the pen would damp its movement when drawing the curve resulting the smoothed response. He wants to see it with out smoothing. |
Forgive my inexperience-I have only used computer programs for measuring. I wasn't doing that in the good ol days I left the scale the same-so the peaks are off scale now.
Post by: Art Welter on March 26, 2009, 10:02:42 PM
I like that much better, looks like Homer Simpson’s teeth now.
And thanks Charlie, glad there are a still a few that remember chart recorders!
Smoothing is so much easier to do now, takes all the “art” out of the pictures.
Art Welter
Post by: John Roberts {JR} on March 26, 2009, 10:09:36 PM
I notice the 2 ohm box was more disciplined, as it should be ( IMO).
JR
PS: I enjoyed hanging out in your office and BS'ing when I was killing time in plant 6. I still run into Jon maybe once every 6 months or so while I'm in meridian food shopping.
Post by: Mac Kerr on March 26, 2009, 10:12:02 PM
| Art Welter wrote on Thu, 26 March 2009 22:02 |
Ivan, I like that much better, looks like Homer Simpson’s teeth now. And thanks Charlie, glad there are a still a few that remember chart recorders! Smoothing is so much easier to do now, takes all the “art” out of the pictures. Art Welter |
I haven't seen a chart recorder since college (except Drs office), but I do still have a Houston Instruments pen plotter. I wouldn't want to try to stop it with my finger though.
Mac
Post by: John Roberts {JR} on March 26, 2009, 10:17:40 PM
JR
PS: FOR ANY READING ALONG WHO STILL DON"T GET IT.. I AM NOT CRITICIZING THE SPEAKER DESIGN... I AM CAUTIONING AGAINST RUNNING 4 AND 8 OHM CABINETS AT 2 OHMS WITHOUT CHECKING THE IMPEDANCE PLOTS.
PPS: The PL380 looks like it should handle 1.75 Ohms OK...
Post by: Michael Hedden Jr. on March 26, 2009, 10:24:10 PM
| Quote: |
For the record I don't think I ever met one single speaker engineer who was willing to concede that another company's data might be honest. "Everybody's a liar... but me". After a while this too becomes background noise.JR |
JR,
Community is an honest company and I've said many times yes here's the word "brutally honest" in their data and I have tremendous respect for Bruce, John, and their team. Jay Mitchell of Frazier is another brutally honest company. Duran Audio, specifically Dr Stuart, brutally honest in presenting his data. I think the very fact that in this very thread you have Danley changing scales to show impedance in ways to assist folks makes my point. I simply am saying if everyone would follow suit this industry would be so much better for it.
Mike Hedden
Tom Danley's number one fan!
Post by: Art Welter on March 26, 2009, 10:32:30 PM
Definitely don’t try to stop those pens!
Art
Post by: Mac Kerr on March 26, 2009, 10:40:59 PM
Mac
Post by: Caleb Dick on March 26, 2009, 10:43:13 PM
Praise for any company from end users is great; praise from anyone at said company about themselves often comes across as marketing, and you know how well pro audio folk love marketing. Please don't read this as a slam on Danley or Mike/Ivan/Tom/etc; those who know me know I'm as big a fan as any.
Caleb
Post by: Art Welter on March 26, 2009, 11:01:55 PM
That’s right, don’t mess with Houston Instruments pen plotters, metal crushers or speaker specifications.
Anyway, I got into binary digital mode about the time you were entering college.
Art
Post by: Mac Kerr on March 26, 2009, 11:05:52 PM
| Art Welter wrote on Thu, 26 March 2009 23:01 |
I got into binary digital mode about the time you were entering college. Art |
That was a long time ago. Last year was my 40th HS reunion.
Everybody out there, think before you act.
Mac
Post by: John Roberts {JR} on March 26, 2009, 11:30:17 PM
| Michael Hedden Jr. wrote on Thu, 26 March 2009 21:24 | ||
JR, Community is an honest company and I've said many times yes here's the word "brutally honest" in their data and I have tremendous respect for Bruce, John, and their team. Jay Mitchell of Frazier is another brutally honest company. Duran Audio, specifically Dr Stuart, brutally honest in presenting his data. I think the very fact that in this very thread you have Danley changing scales to show impedance in ways to assist folks makes my point. I simply am saying if everyone would follow suit this industry would be so much better for it. Mike Hedden Tom Danley's number one fan! |
And Chuck McGregor formerly at EAW is honest, and I even believe the lads at Peavey, while I know precious few still there, were honest.. and all those other companies I didn't mention.
My experience from a couple decades in the industry is that most companies are honest, or think they are. Some marketing types can get a little too enthusiastic, and depending upon the balance of power between engineering and marketing some less than comparable specifications get used. Large companies who compete in multiple market segments may even tune their specifications to be in the lingua franca for a modest performance market rather than high Latin of the church.
Danley appears to be a very engineering driven company, appealing to a high performance market, so anything less than very conservative presentation of data would be a critical mistake.
If you are aware of direct competitors in your marketplace who are being deceptive in product specifications either by omission, or putting their finger on the pen in any way call them on it. You could do Brand D vs, Brand X as measured by brand D, vs what brand X measures. Measure their box side by side with yours using your test gear... If they protest, invite their engineers to your facility to participate in the measurements.
This might make a fun add on section for your website. I know everybody loves seeing liars exposed.
If you wish to be lass confrontational, write a tutorial on how specifications can be fudged with real examples. I bet the AES would accept that as a formal paper if well documented.
Finally I'd like to give Ivan a shout out... he seems to always be crunching data and making measurements which I know takes more time and effort than people appreciate.. Thank You Ivan.
JR
Post by: John Roberts {JR} on March 26, 2009, 11:51:34 PM
| Art Welter wrote on Thu, 26 March 2009 22:01 |
Mac, That’s right, don’t mess with Houston Instruments pen plotters, metal crushers or speaker specifications. Anyway, I got into binary digital mode about the time you were entering college. Art |
One of my early coop jobs back in the '60s was at a metals factory where there was a bunch of cut off saws, presses, and punches back in the piece-work area. All too many machine operators were missing digits from decades on that or similar jobs. Even back in the 60's most of the presses or punches had two buttons, so in theory both hands were on deck and accounted for, but the folks who were paid on how many units they cranked out would cheat the buttons by leaning on one or both with their elbows while feeding parts with the free hands,,, I'm glad to say I didn't see any fresh meat or people cheating the safety switches while I was there, but I was only there 3 months and my job was QC so I only went back there when a customer complained about a batch that wasn't cut the right length or some other defect.
A good reminder of how blessed we are to be able to work at something we actually enjoy.
JR
Post by: Karl P(eterson) on March 27, 2009, 09:12:35 AM
| Michael Hedden Jr. wrote on Wed, 11 March 2009 07:35 | ||
Eytan, We have been blessed with an abundance of work including Karl Peterman's LCR auditorium project and a stadium project that Ivan and I will be tuning this week comprised of over 400 cabinets. Several miles will be logged on the old legs this week! Predicated on weather cooperating so we can get outside, the information for both models will be up on the site within a week or so. I spent an hour or so last night listening to the new subs. These are going to be bringing a lot of smiles and head turns to a lot of people. Mike Hedden Danley Sound Labs, Inc. |
Its Karl Peterson buddy
Karl P
Post by: Phillip_Graham on March 27, 2009, 03:08:43 PM
The way the drivers are tucked in there makes it easy to forget this is a 58 cubic foot (1.64 m^3) box, or that the drivers are substantially larger than an already large 18" driver.
It would seem that this box provides both more real output and about 20Hz in real extension over the 4 typical dual 18" boxes that would occupy the same cubic space.
It would be pretty cool to do be able to do a full on loud rock show in a 2k venue with only one sub per side...
Post by: Ivan Beaver on March 27, 2009, 07:59:54 PM
. One of my little "dreams" is to have a REAL demo room at a trade show. And by that I mean having several different manufacturers products side by side
. And if a particular manufacturer has a problem with what is being done or saying that the particular product of theirs being used is "defective" then tell them to bring one down from their booth. I bet people would be lined up out the door to see/hear that!! "Would you believe what they are doing down there!".
The new Jack in the Box commercials are boarding on that.
"If I've saying anything that is not true-do something about it"-as he rips off his sleeves.
But you really don't need to measure a lot of loudspeakers to get an idea of how specs are "stretched". Just look at the spec sheets that show measured data-and go ahead and assume that the measurements are correct (I suspect they are-or close enough anyway), and put your own numbers on the graphs such as sensitivity- low and high cutoffs etc.
Now compare those numbers to the published numbers on the front of the spec sheet. You will see some very different results-from a lot of manufacturers, and others are right on the money.
Now when it comes down to coverage angles and how well the polars/balloons agree with the printed coverage angle-that is a whole different story.
Now for the manufacturers that only provide a couple of simple numbers-you cannot find the errors so easily. But let me say, that there are products out there that are easily 15dB off and more!
Gathering loudspeaker data accurately is A LOT harder than people think. Sometimes I spend literally spend hours getting the arrival time correct to get a decent phase response.
It can be very frustrating at times-but challenging and rewarding in all that I learn.
Thanks for the comment
Post by: John Roberts {JR} on March 27, 2009, 10:27:08 PM
| Ivan Beaver wrote on Fri, 27 March 2009 18:59 |
That may happen sooner than you think . One of my little "dreams" is to have a REAL demo room at a trade show. And by that I mean having several different manufacturers products side by side . And if a particular manufacturer has a problem with what is being done or saying that the particular product of theirs being used is "defective" then tell them to bring one down from their booth. I bet people would be lined up out the door to see/hear that!! "Would you believe what they are doing down there!". The new Jack in the Box commercials are boarding on that. "If I've saying anything that is not true-do something about it"-as he rips off his sleeves. |
Enjoy the dream, but know that it's only a dream.. It doesn't work on several levels, but it's fun to ponder... I wanted to have an amp tug of war,, where two amps connect their outputs together and like those robot wars the winning amp blows up the loser... but i can't even justify this on an engineering basis let alone marketing.
| Quote: |
But you really don't need to measure a lot of loudspeakers to get an idea of how specs are "stretched". Just look at the spec sheets that show measured data-and go ahead and assume that the measurements are correct (I suspect they are-or close enough anyway), and put your own numbers on the graphs such as sensitivity- low and high cutoffs etc. Now compare those numbers to the published numbers on the front of the spec sheet. You will see some very different results-from a lot of manufacturers, and others are right on the money. |
I repeat... A way that IMO could be done is to set up comparisons between Brand D, Brand X and what Brand X says... put this up on your website. If brand X complains let them come show you.
I recall while working at Peavey when one competitor brazenly listed one of our products in a magazine advertisement as one of several brands that their wonder product had better specifications than, we pointed out that they really were mistaken (they really were wrong) and that ad was never seen again. I will give them the benefit of the doubt, that they probably believed their POS was better than Peavey.. a lot of people suffer that same delusion (very long story).
| Quote: |
Now when it comes down to coverage angles and how well the polars/balloons agree with the printed coverage angle-that is a whole different story. Now for the manufacturers that only provide a couple of simple numbers-you cannot find the errors so easily. But let me say, that there are products out there that are easily 15dB off and more! |
Sounds like red meat for an AES paper... don't name names but diagram how the specifications are manipulated to create erroneous impressions. It's a small industry they will be embarrassed into changing their act and you might get to wear a ribbon at an AES show. I hear the booth babes go for blue ribbons.
| Quote: |
Gathering loudspeaker data accurately is A LOT harder than people think. Sometimes I spend literally spend hours getting the arrival time correct to get a decent phase response. It can be very frustrating at times-but challenging and rewarding in all that I learn. Thanks for the comment |
Yup, I get that. I understand enough about speakers to understand that I really am just scraping the surface.. I have actually been inside more than one anechoic chamber... which is a little cool when you consider how many people have never been in one. They both sounded exactly the same... go figure.
Write a white paper on "speaker specification truth".. the world will be a little smarter and that's always a good thing. IMO, that is win-win marketing.
JR
Post by: Ivan Beaver on March 27, 2009, 10:55:23 PM
| John Roberts {JR} wrote on Fri, 27 March 2009 22:27 |
[Write a white paper on "speaker specification truth".. the world will be a little smarter and that's always a good thing. IMO, that is win-win marketing. JR |
Rather than quote everything (and you are right on those) the idea of putting data from other manufacturers along with Danley-measured in exactly the same way-has already been considered and may be in the works in the future-Infocomm and lots of new stuff has to come first.
I have already started a paper on such a subject-along with many others-to be posted at some time in the future.
These things take time ya know
Post by: John Roberts {JR} on March 27, 2009, 11:07:06 PM
I tried to learn stuff here by posting more, but it seems to be making me dumber.
JR
Post by: Ivan Beaver on March 27, 2009, 11:27:01 PM
| John Roberts {JR} wrote on Fri, 27 March 2009 23:07 |
Writing stuff out forces you to share what you think you know with the other half of your brain... I always learned things from my writing projects... I tried to learn stuff here by posting more, but it seems to be making me dumber. JR |
Would that be because of the audience?
I am giving a talk as part of a panel at an upcoming Atlanta AES meeting (with Charlie Hughes-talk about PRESSURE!!!
). I have never done anything like that-for that type audience.I am not a "public speaker" type of person (yet
), but do a lot of training on console operation (but then my audience is different), and am a bit nervious, but I figure it will make a better person out of me. And getting prepared will be also be good for me. I really need to get started.
Post by: John Roberts {JR} on March 28, 2009, 11:54:06 AM
Don't be nervous about the AES meet, have some fun with it. They should be a receptive and friendly audience. Public speaking is never easy, but it helps that you know what you're talking about, and what doesn't kill you makes you stronger.
JR
Post by: Iain_Macdonald on March 29, 2009, 01:05:06 PM
I'll defend John R for questioning the impedance plots, for a different reason. Most impedance plots that appear from manufacturers, have no indication whether they are simple or complex plots, or the methods used. Using a current source or voltage divider method, the complex(reactive XL & XC) and simple(resistive R) are viewed together. OK this gives a general impression of what's happening, but not the whole story. An impedance Nyquist or Bode plot would be better. Current phase would also be helpful.
For an amplifier that is marginal at 2ohms, the 221 looks like it might be a difficult load. Running it to 90Hz, it has three areas that are capacitive (the down slope).
Iain.
Post by: John Roberts {JR} on March 29, 2009, 02:08:33 PM
| Iain Macdonald wrote on Sun, 29 March 2009 12:05 |
Hi, I'll defend John R for questioning the impedance plots, for a different reason. Most impedance plots that appear from manufacturers, have no indication whether they are simple or complex plots, or the methods used. Using a current source or voltage divider method, the complex(reactive XL & XC) and simple(resistive R) are viewed together. OK this gives a general impression of what's happening, but not the whole story. An impedance Nyquist or Bode plot would be better. Current phase would also be helpful. For an amplifier that is marginal at 2ohms, the 221 looks like it might be a difficult load. Running it to 90Hz, it has three areas that are capacitive (the down slope). Iain. |
Thanx.. My understanding is that minima's are pretty much resistive, and conventional (non-class D) power amps are equally bothered by leading or lagging load angle. This too is pretty well factored into the dance.
I repeat these speakers are not unusual (well perhaps a 2 ohm box is not common). My caution is in sizing amplifiers, and sharing my preference to not load amps to their max. Just like I don't advise operating loudspeakers to their max output limits.
FWIW class D amps don't much care about load angle, but other amps do, so regions immediately "around" the impedance minimums can matter for thermal headroom, like Ian said.
JR
Post by: Ivan Beaver on March 29, 2009, 02:45:58 PM
| Iain Macdonald wrote on Sun, 29 March 2009 13:05 |
Hi, I'll defend John R for questioning the impedance plots, for a different reason. Most impedance plots that appear from manufacturers, have no indication whether they are simple or complex plots, or the methods used. Using a current source or voltage divider method, the complex(reactive XL & XC) and simple(resistive R) are viewed together. OK this gives a general impression of what's happening, but not the whole story. An impedance Nyquist or Bode plot would be better. Current phase would also be helpful. For an amplifier that is marginal at 2ohms, the 221 looks like it might be a difficult load. Running it to 90Hz, it has three areas that are capacitive (the down slope). Iain. |
OK Iain-just for you-here are the same plots with no smoothing and the phase plots included.
Since the curve are via TEF-the standard TEF impedance method is used (that part should be obvious
) which is a voltage divider.The reason the phase is not included on the normal published impedance plots is that most people would have no idea what they are looking at.
And it would get confusing to them.NOW I ASK YOU-What other manufacturer provides the phase response on an impedance graph? None that I am aware of.
ALSO How is this additional information going to be helpful to you and what other loudspeakers are you going to compare it to?
Heck-most don't even provide a basic impedance plot-and yet you really want to question in depth somebody who provides more information than most other manufacturers.
Enjoy
Post by: John Roberts {JR} on March 29, 2009, 04:09:54 PM
I appreciate the detail because it pretty much reinforces what I thought I knew, i.e. load angle is close to 0' at minima.
Lets use this as an opportunity to educate readers, this is the Classic LAB, not the marketplace. Amplifier heat dissipation and to a lesser extent reliability (due to secondary breakdown) are stressed by the combination of load angle and impedance. A purely reactive load angle would draw peak current when the power amplifier devices have the maximum voltage drop across them for worst case VxI. For those still playing along at home, it is a good thing that the maximum load angle deviation shown on the plots occurs well above impedance minima.
Danley boxes IMO don't require special defense in this regard and I am sorry if it looked like I was singling them out. I was just trying to add some relevant insight about how amps feel about these squiggles.
JR
Post by: Ivan Beaver on March 29, 2009, 06:04:04 PM
| John Roberts {JR} wrote on Sun, 29 March 2009 16:09 |
Lets use this as an opportunity to educate readers, this is the Classic LAB, not the marketplace. Amplifier heat dissipation and to a lesser extent reliability (due to secondary breakdown) are stressed by the combination of load angle and impedance. A purely reactive load angle would draw peak current when the power amplifier devices have the maximum voltage drop across them for worst case VxI. For those still playing along at home, it is a good thing that the maximum load angle deviation shown on the plots occurs well above impedance minima. Danley boxes IMO don't require special defense in this regard and I am sorry if it looked like I was singling them out. I was just trying to add some relevant insight about how amps feel about these squiggles. JR |
Regarding the phase angle of impedance, 0
Post by: Franz Francis on March 30, 2009, 09:40:28 AM
I’ve already set my pick on the TH-221.
I can just imagine what it is capable of properly powered out in the open concert, festival environment.
My experience with the TH-115 is indoors (Small rooms) one can probably get away with budget constrained type amplifiers but out in the open for large concerts and festivals they need to be properly powered and the reason why I am powering them at twice the RMS. The Lab Gruppen FP+13,000, (4400W/4 ohm ch) two boxes per channel worked out to be very satisfying for me.
A number of leading amplifier manufacturers already have units in production that are able to meet the power requirement of the new subs in the one box per channel configuration (Two or four ohm).
Powersoft K20, K10… Lab Gruppen PLM 14,000, FP+14,000, FP+13,000, Crown I-Tech HD 12,000, Macro Tech 12,000 are just a few I can think of.
Franz
Post by: Langston Holland on March 30, 2009, 11:25:53 AM
| Franz Francis wrote on Mon, 30 March 2009: |
By the looks of it the TH-115 is finally dethroned as the best loudspeaker in the world :} |
Naa... Not IMO. The only thing that might take the throne from the TH115 is the TH212, but even then they'll probably be seated right next to each other. The smaller subs are the deal for 95% of concert work IMO, while the big ones are going to be a great deal of fun for the remaining 5%. I'm sure Ivan the Terrible will be sending me a pair of the TH212's and TH221's to demo quite soon now that he's freed up to do full time what he was supposed to be doing all along.
Right Ivan? :)
Post by: Ivan Beaver on March 30, 2009, 11:48:08 AM
That is part of the reason Danley offers so many different subs (and more to come)-different people need different things.
One of the driving forces behind the TH212 is for people who wanted to put subs under a short stage and have a serious output. The ones that have fit the bill in the past have been limited in output level and freq response.
That and the fact that you can easily put 12 of them in 3'deep of truck space is also a nice benifit
The larger subs are for people who only want to take one or two per side and get quite loud.
Of course there are tradeoffs in all of them-size-output-freq-price-weight and so forth.
Post by: Jens Brewer on March 30, 2009, 12:56:35 PM
| Ivan Beaver wrote on Fri, 27 March 2009 23:27 |
I am giving a talk as part of a panel at an upcoming Atlanta AES meeting (with Charlie Hughes-talk about PRESSURE!!! ) |
Ivan, when and where? I haven't heard anything from the local chapter about it. If I'm in town, I'll definitely go.
Post by: TrevorMilburn on March 30, 2009, 12:59:27 PM
Right, where do I sign up for them...?
Trevor
Post by: Christian Tepfer on March 30, 2009, 01:06:09 PM
| TrevorMilburn wrote on Mon, 30 March 2009 18:59 |
I still find it amazing that some deranged idiots (read AV fanatics) are thinking of using the 221s in home theatre set-ups! Who in their right mind would want that amount of output and extension in their own homes? You could lose your neighbours, cause structural damage to your house and probably lose your wife into the bargain - can you imagine trying to explain the sudden appearance of two new 50 cubic feet wooden boxes in your sitting room? Right, where do I sign up for them...? Trevor |
Structural damage? What do you build your homes with? 2x4 Wood?
Post by: Bob Kenton on March 30, 2009, 01:48:49 PM
| Christian Tepfer wrote on Mon, 30 March 2009 18:06 | ||
Structural damage? What do you build your homes with? 2x4 Wood? |
Yip, and worse yet.........stucco!
Post by: Ivan Beaver on March 30, 2009, 03:00:54 PM
Post by: Ivan Beaver on March 30, 2009, 03:05:53 PM
The problem is that with all the BS in that market-loudspeakers that claim to reproduce it are so low in level so as to be unusable-but numbers are all that matter to a lot of them.
I don't think they realize how loud these things would get in a home.
Oh well-as long as the check clears
Post by: Iain_Macdonald on March 30, 2009, 03:11:34 PM
| Quote: |
OK Iain-just for you-here are the same plots with no smoothing and the phase plots included. Since the curve are via TEF-the standard TEF impedance method is used (that part should be obvious Rolling Eyes ) which is a voltage divider. The reason the phase is not included on the normal published impedance plots is that most people would have no idea what they are looking at. Confused And it would get confusing to them. NOW I ASK YOU-What other manufacturer provides the phase response on an impedance graph? None that I am aware of. ALSO How is this additional information going to be helpful to you and what other loudspeakers are you going to compare it to? Heck-most don't even provide a basic impedance plot-and yet you really want to question in depth somebody who provides more information than most other manufacturers. |
Ivan,
Thanks for the plots. You need to read my previous post again, with the volume turned down.
No other manufacturers, that I know of, produce really detailed specs. But neither do you lot. So how about the impulse plot and the CSD/Waterfall. Burst decay, via Wavelet/convolution, would also be nice. Tom is in to wavelets. OK, I am only joking. Really?
Does the phase trace help? Yes it does thanks. I meant to mention inductive problems in the other post, so it might have looked unfinished. Simple horns and reflex boxes don't usually have that triple hump. Though you might see it with a bandpass box. The 221 has a couple of steep transitions in the inductive and capacitive areas. I would definitely want to test out any amp being used with it. Especially if it was class D.
| Ivan |
Heck-most don't even provide a basic impedance plot-and yet you really want to question in depth somebody who provides more information than most other manufacturers. |
Oh I forgot my place in the pecking order. I better go back to being a mushroom. Customers are always wrong!
Iain.
Post by: John Roberts {JR} on March 30, 2009, 03:55:04 PM
| Iain Macdonald wrote on Mon, 30 March 2009 14:11 |
The 221 has a couple of steep transitions in the inductive and capacitive areas. I would definitely want to test out any amp being used with it. Especially if it was class D. Iain. |
If you know something about class D that I am not seeing please share.
There are pretty well documented interactions with class D output filters regarding load impedance and top octave frequency response. Some class D amp makers already claim recapture of back EMP so any inductive kick seems like more gravy for that gravy boat (I am neither confirming or denying those claims).
Class D AFAIK is not subject to secondary breakdown or VxI heating issues like conventional linear bipolar output stages, so what do you have in mind?
JR
Post by: Iain_Macdonald on March 30, 2009, 04:24:13 PM
| John Roberts {JR} wrote on Mon, 30 March 2009 20:55 | ||
If you know something about class D that I am not seeing please share. There are pretty well documented interactions with class D output filters regarding load impedance and top octave frequency response. Some class D amp makers already claim recapture of back EMP so any inductive kick seems like more gravy for that gravy boat (I am neither confirming or denying those claims). Class D AFAIK is not subject to secondary breakdown or VxI heating issues like conventional linear bipolar output stages, so what do you have in mind? JR |
John,
Just to make sure I wasn't heading up the wrong path. Today I had a long and very interesting conversation with the designers of one of the latest monster power amps. They confirmed my thoughts about highly inductive loads, interacting with the output network of a Class D, just as you mentioned. But not just HF. A couple of these amp types tested, initially displayed ringing, as a prelude to oscillation. For obvious reasons I am not going to mention brands, or things will just degenerate. But they have been modified since release, because of this problem. But instability was also an issue with high power mosfets, so nothing new. The point I was making about the 212, was purely about the unusual load presented to the amp. As I said in the other post. " A marginal amp.... Note the word marginal. It would be interesting to do a spice model of the 812 as an amp load.
Iain.
Post by: John Roberts {JR} on March 30, 2009, 05:04:38 PM
| Iain Macdonald wrote on Mon, 30 March 2009 15:24 |
John, Just to make sure I wasn't heading up the wrong path. Today I had a long and very interesting conversation with the designers of one of the latest monster power amps. They confirmed my thoughts about highly inductive loads, interacting with the output network of a Class D, just as you mentioned. But not just HF. A couple of these amp types tested, initially displayed ringing, as a prelude to oscillation. For obvious reasons I am not going to mention brands, or things will just degenerate. But they have been modified since release, because of this problem. But instability was also an issue with high power mosfets, so nothing new. The point I was making about the 212, was purely about the unusual load presented to the amp. As I said in the other post. " A marginal amp.... Note the word marginal. It would be interesting to do a spice model of the 812 as an amp load. Iain. |
Well I can't trump your call to (unnamed) authority...
Class D amps do have a slightly more difficult feedback stability task, compensating for the delay of an output filter to convert PWM to audio in the loop, but AFAIK these stability issues are mainly top octave phenomenon where the delay time can be significant wrt wavelength.
Revisiting the phase plot it does deviate from resistive (capacitive?) at the upper end of the chart but impedance looks like it is rising too. Was this the problem for your contact? Or did they experience instability at low frequency where the load phase angles pass through zero?
If these cabinets are a problem for any commercial amp maker out there (class D or otherwise) they should chime in here and now, otherwise I will ASSume they are not. I expect throwing 4x several popular 8 ohm cabinets in parallel could lead to some pretty nasty plots.
JR
Post by: Tom Danley on March 30, 2009, 09:32:49 PM
I think there are two potential ways for the electrical phase to be an issue.
In a conventional amplifier, the heat produced by the output devices is proportional to the voltage across it times the current it is conducting and limits what the transistor can do.
The “Safe operating area” for the transistor (s) defines sort of a bowtie shape so far as a V and I graph of permitted load angle, that is to say combination of voltage and current.
What one finds is that say a 4 Ohm resistive load produces less transistor heating than a
4 Ohm load which has capacitive or inductive reactance.
What one sees with a fully reactive load (90 degree phase angle) is that the current maximum happens when the output voltage is crossing zero and this is a very difficult load (think 5mfd across the amp terminals).
An amplifiers protection circuit is supposed to limit the current when the load angle would have driven it outside its “happy” zone, traveling significantly outside of which is where flaming silicon death normally occurs.
This kind of linear amplifier typically has a small series decoupling inductor at the output terminals to de-couple the amplifier at high frequencies, series L, no problem.
Pulse width modulators (digital amplifiers) were used on servo motors for about 20 years before the switch frequency was high enough for “audio” use.
These work by adjusting the duty cycle of pairs of switches arranges in an H bridge (usually). Instead of being part way on, they are on or off.
The switching device heating is the sum of the I^R loss while “on” and the losses charging the gate and other capacitances. This allows them to approach or exceed 90% efficiency depending. The huge up side that made them ideal for driving motors is they don’t particularly care about load reactance as unlike the linear amplifier, these switches are in effect either on or off.
While the output devices have different rules, the larger difference is in the pulse width modulator. This is not a Voltage amplifier, this is not a Current amplifier, it is a duty cycle controller. If you want to put out a specific voltage, then you need to close the loop around the output voltage it’s producing and the one you want.
Here is the rub, the output is a rail to rail signal, this has to be integrated into the actual signal. This is done with a low pass filter. If one had a loop to close (like here), then Bode criteria severely limits what kind of filter you can use. It is this filter or the difficulty involved, that pushes the switch frequency so much higher than simple nyquist criteria would suggest.
Without a loop, you can use any filter order you choose. I wouldn’t be surprised if “modern” audio switching amplifiers had two sets of filters, one for the output and one for the closed loop. As John suggested, problems here are up high, closer to the region where the filter corner is, lower down the filter has a larger phase margin..
Anyway, back to speakers as a load and spice models, because it is electrically and acoustically a series of L’s, R’s , a variable R and C’s, one finds that where ever there is a either a peak or a dip, one finds a point where the reactance’s have conjugated or “self canceled” leaving the resistive term which appears in both the “one over” and normal terms depending.
Up high, one sees the impedance rise and phase shift caused by the coil of wire’s geometry.
Now, so far as how reactive is a speaker, the greater the phase shift (the farther it is from resistive), the more heat a linear amplifier produces, the greater possibility you might be able to tickle the safe area protection.
When you look at the impedance and phase plot , this is what you see.
Now, in general, the greater the difference between the peaks and dips, the larger the phase shift in between is. This larger or smaller difference reflects the lesser or greater acoustic loading (or broad band resistive loss)
As you load a driver with acoustic load, you see the phase shift stays closer to zero reflecting a larger resistive load on the driver. A “perfect” horn loaded driver is
Bottom line, in general for a one way system, the greater the speakers sensitivity (efficiency) is, the greater the acoustic load shows up in the electrical impedance making it less reactive and more resistive.
In the case of any of the Tapped horns, increasing the sensitivity of the drivers via increased acoustic resistance, would reduce the load reactance and raised the impedance relative to the same drivers in say a vented box .
Anyway, hope this helps.
Best,
Tom Danley
Post by: TrevorMilburn on March 31, 2009, 07:28:09 AM
| Quote: |
What do you build your homes with? 2x4 Wood? |
No, that's the Americans - my house is an 1871 Victorian town house with solid 24inch (I kid you not) brick external walls. The upper floor beams are 15 inches by 3 inches with 1 inch thick pitch pine floor boards - so the only weak point would be the windows - oh, yes and the wife, and the neighbours. But what a talking point when you bring your friends home for a drink...!
For Mike or Ivan :- how do the 21inch monsters compare sonically, say with the TH50 or TH115 - are they completely neutral or do all the Danley tapped horns have a specific 'sound' in an A:B comparison?
I still find it fascinating that after years of using smaller and smaller drivers in Subs that many companies are going over to 21inch and above drivers - is it purely that (large) transducer technology is improving (again?) or is it simply back to the Laws of Physics?
Regards,
Trevor
Post by: Justin Stern on March 31, 2009, 07:40:25 AM
The 212 is the best sub I have ever heard. I think it blows the TH-115 away. It has an unbelievable punch in the chest feeling and goes down darn low!
This is going to be a winner for Danley!
Post by: Justin Stern on March 31, 2009, 07:43:38 AM
Post by: Franz Francis on March 31, 2009, 08:38:54 AM
Franz
Post by: Michael Hedden Jr. on March 31, 2009, 10:16:20 AM
| Quote: |
For Mike or Ivan :- how do the 21inch monsters compare sonically, say with the TH50 or TH115 - are they completely neutral or do all the Danley tapped horns have a specific 'sound' in an A:B comparison? I still find it fascinating that after years of using smaller and smaller drivers in Subs that many companies are going over to 21inch and above drivers - is it purely that (large) transducer technology is improving (again?) or is it simply back to the Laws of Physics? Regards, Trevor |
Trevor,
All the Tapped Horns have a very similar sound. If you play a song that doesn't have much below 50Hz folks have a hard time determining which sub is on. In other words the THmini sounds like the TH115, etc. The difference becomes clearly audible when you move to material with more low frequency information. The lower the cutoff of the material the corresponding box will clearly be revealed.
The majority of Danley's subs utilize 12" or 15" transducers and the TH812 uses 8-12's so that should tell you what our overall opinion is regarding driver size. The TH221 and the TH812 were designed for the "you have to be kidding me" market. The 21" was utilized primarily for large digital cinema applications where a single sub would have substantially more output at 20Hz than a bank of four TH50's. Also there is a certain element of the market that buys with its eyes and believes bigger has to be better.
Thanks,
Mike Hedden
Danley Sound Labs, Inc.
Post by: John Roberts {JR} on March 31, 2009, 10:23:25 AM
My suspicion is it was customer driven. The customer is always right, even when wrong.
JR
Post by: Iain_Macdonald on March 31, 2009, 01:52:50 PM
I repeat the key phrases from of my original post. "A marginal amp"... ....especially if it's class D
An amp driving this speaker is seeing three impedance peaks. This is unlike a regular cabinet, where the amp is only seeing the down side of the resonant peak,(the capacitive side). A Tapped Horn™ has the advantage of being able to produce below resonance without the usual complications. So an amp driving a 212 is in fact seeing three 'inductive' areas. You mention Zma as dominating. Yes but you have three rapid transitions to consider. That's why I say that I would like to monitor a marginal D amp when used on this particular cabinet. For marginal read: unstable control loop, poorly designed OP filter,etc. At the back of mind is the issue of dynamic impedance, which is not measurable by simple swept sine. You might remember the papers by Matti Ottala from Genelec, which showed a bass driver in a cabinet dipping from 8 to 1ohm under music conditions. Even though the accepted 8ohm figure with 80% was factored in.
Iain.
Post by: TrevorMilburn on March 31, 2009, 02:41:54 PM
Regards,
Trevor
Post by: Tom Danley on March 31, 2009, 02:44:22 PM
A “marginal amp” of any class is a polite way to say it is insufficient.
It has been some time since I designed 100 Amp pwm controllers for heating elements and servomotors in a BT-7 so I am out of date to a degree.
That being said, what I saw was switched amplifiers were much more immune to load reactance than a linear amplifiers, they were happy driving a very reactive load.
The advantage they had was for an AC signal, the Current and Voltage could be wildly separated in phase. A regenerative circuit (initially called a Cuk Buck/boost circuit) can be used to use the load’s reactive energy to charge the power supply. This kind of controller can operate in all four quadrants.
What you said is true here is why, the loudspeaker is a “perfect motor generator” attached to a radiator, with the drivers Rdc and Le in series electrically.
The motor converts Current into Force and if moving, as a generator, produces a voltage proportional to the velocity and the motor’s force sensitivity (Force per Amp) and is in series with the Rdc and Le. This is back EMF, the more sensitive the motor is, the greater the back EMF is at a given velocity.
In a condition like clipping, because this back EMF is in series, it is added (or subtracted) to the amp signal. In a case like clipping, the back EMF may be momentarily the opposite voltage and so the amplifier voltage is added to the EMF, causing more current to flow than is possible given the Rdc and amplifier voltage. In other words, that clipped or square wave especially signal can produce the current of a lower impedance than the Rdc.
An easy way to imagine this is a DC motor driven with a low frequency square wave. You are telling it to turn at say 2000 RPM, the current drawn is very small because the motor is turning 2000RPM so the Back EMF is nearly equal to the input Voltage.
You reverse the Polarity, now the signal tells it to run the same speed but opposite direction. Momentarily after the transition, you have the new input voltage, plus the EMF from the motor turning the wrong way, applied across the Rdc. A speaker Voice coil is also a DC motor.
In practice, one uses a low pass crossover so signals like this are certainly not part of the normal job of a subwoofer.
All that being said and known, I am not following reasoning suggesting the 212 Tapped horn might be more susceptible to causing an amplifier problem, than countless other speakers. Can you show some product impedance curves that have “much less” load reactance?
Also, often such amplifiers are used to drive full range speakers which have passive crossovers, the sum of which often results in much larger load reactance’s and “warts”.
If a switching amp were going to misbehave or have a problem with a reactive load, it would I would think be more audible / be more susceptible to problems the higher in frequency, the issue is because the amplifier closed loop margin and “spare gain” is less and less as you go up.
In any case, if we hear of one of the new wonder amps not working as expected, we will certainly start up a “not recommended” amp list.
Best,
Tom
Post by: John Roberts {JR} on March 31, 2009, 02:47:18 PM
| Iain Macdonald wrote on Tue, 31 March 2009 12:52 |
Tom & John R, I repeat the key phrases from of my original post. "A marginal amp"... ....especially if it's class D An amp driving this speaker is seeing three impedance peaks. This is unlike a regular cabinet, where the amp is only seeing the down side of the resonant peak,(the capacitive side). A Tapped Horn™ has the advantage of being able to produce below resonance without the usual complications. So an amp driving a 212 is in fact seeing three 'inductive' areas. You mention Zma as dominating. Yes but you have three rapid transitions to consider. That's why I say that I would like to monitor a marginal D amp when used on this particular cabinet. For marginal read: unstable control loop, poorly designed OP filter,etc. At the back of mind is the issue of dynamic impedance, which is not measurable by simple swept sine. You might remember the papers by Matti Ottala from Genelec, which showed a bass driver in a cabinet dipping from 8 to 1ohm under music conditions. Even though the accepted 8ohm figure with 80% was factored in. Iain. |
A marginal amp is a marginal amp using any technology.
Are you suggesting the Danley is a more difficult load than other loudspeakers? Whether it has one or ten inductive regions doesn't matter IMO as much as where and how severe that reactive region is.
I generally come from a perspective that is defending the amplifier more than loudspeaker. I have seen many scary examples (mostly due to poorly designed passive crossovers) of killer speakers.
I find this topic of academic interest. This thread may have triggered this discussion more because of the detailed plots, than the actual numbers on those plots. I will defer to Tom's judgement here since he seems adequately competent to address both the speaker load and amplifier drive sides of this discussion.
JR
PS: I stopped listening to Ottola a few decades ago when he tried to reinvent slew rate limiting. I am somewhat aware of amplifier/box interactions, from years at a company who designed and sold both.
edit- oops Tom beat me to the draw...
Post by: Langston Holland on March 31, 2009, 05:39:52 PM
We need a whole lot more people in the world like you JR.
Post by: John Roberts {JR} on March 31, 2009, 07:15:22 PM
| Langston Holland wrote on Tue, 31 March 2009 16:39 |
Tom seems adequately competent to me too! ) |
I guess I sound a little arrogant saying that... I am just smart enough to realize how much smarter Tom is than me...
JR
Post by: Langston Holland on March 31, 2009, 10:57:16 PM
Post by: Chris Cox on April 07, 2009, 07:50:54 PM
Post by: Antone Atmarama Bajor on April 08, 2009, 03:35:13 AM
They don't actually have a standard for what is happening bellow 35Hz in exhibition houses (or not yet that I know of). Often when being mastered for exhibition the engineers pretend that the content bellow 35Hz doesn't exist or ignore it.
The reasons being
A: A majority of "Subs" don't really perform well bellow 40Hz.
B: Room modes became very difficult to control in those ranges.
Anyhow the maximum summed 1/3 octave SPL for the LFE should be ~115dB Averaged listening position.
The maximum summed 1/3 octave SPL for Front and Surrounds should be 105dB @ listening possition.
Those numbers might seem low to you, but its actually quite loud, and some people often complain when an exhibitionhouse is running the system calibrated to "Full Scale Cinema" headroom.
Sorry to derail the thread for a moment.
Cary on.
Antne=
Post by: Michael Hedden Jr. on April 08, 2009, 08:38:26 AM
[/quoteIf I remember correctly the 812 weights around 450lbs.
The 812 will go significantly lower than the 115 or the 212 and a single cabinet with its combination of sensitivity of 110dB from 100Hz-30Hz and 5600 watts RMS means it will get louder as well. It's also less money than four TH212's.
Mike Hedden
Danley Sound Labs, Inc.
Post by: Scott Raymond on April 08, 2009, 10:04:35 AM
| Antone Atmarama Bajor wrote on Wed, 08 April 2009 02:35 |
properly tunned theaters SPL(THX/ISO 2969) should be the same from exhibition house to exhibition house (at least at average listening possition) They don't actually have a standard for what is happening bellow 35Hz in exhibition houses (or not yet that I know of). Often when being mastered for exhibition the engineers pretend that the content bellow 35Hz doesn't exist or ignore it. The reasons being A: A majority of "Subs" don't really perform well bellow 40Hz. B: Room modes became very difficult to control in those ranges. Anyhow the maximum summed 1/3 octave SPL for the LFE should be ~115dB Averaged listening position. The maximum summed 1/3 octave SPL for Front and Surrounds should be 105dB @ listening possition. Those numbers might seem low to you, but its actually quite loud, and some people often complain when an exhibitionhouse is running the system calibrated to "Full Scale Cinema" headroom. Sorry to derail the thread for a moment. Cary on. Antne= |
Interesting point as I just ran across this in a recent Cinema re-install. They created a standard for capabilities and the Producers and Engineers "over-used" it. Theaters would turn down the master at the Cinemas because of complaining patrons and then run into the problem of dialog in the center channel being too low. I ended up tweaking the center channel up for these folks to compensate probably at the expense of changing the LCR "audio image". This was on the first show they had in there, I haven't talked to them since the second so I don't know how it compared. The dialog on parts of the first one I thought wasn't recorded that well (Gran Torino) but I had nothing to compare with so I'm not absolutely sure about it yet.
P.S. Thanks to Brian Bolly who emailed a bunch of info on Cinema. I definitely had a "bit" of reading to do to get anywhere up to speed on Cinema "things".
Post by: John Roberts {JR} on April 08, 2009, 10:42:02 AM
JR
Post by: Antone Atmarama Bajor on April 08, 2009, 12:42:15 PM
And I'm pretty sure that god awful movie version of RENT exceeded SPL exposure in the first few minutes Talk about squashed. I saw it at a NARAS event at Skywalker, I don't think my ears have ever been so fatigued after seeing a movie.
I'm pretty sure most good engineers would make sure there isn't too much energy in the ranges bellow standards. I think most of their studio subs are more than capable in a posting room. But for the most part, exhibition house subs have been lacking. I've often heard some of the JBL 18" Cinema subs make nasty sounds. When the film has had some ultra low content.
And if one adds almost an octave lower, wouldn't that make the sum of 1/3rd ocatave bands higher, meaning either they would have to raise the 115dB or the resulting 115dB would seem quieter?
The system is normally calibrated with summed 1/3 octave banded pink noise.
LFE are 95dB with 20dB of headroom for peaks. F and Surr are 85dB with 20dB of headroom.
If you don't know about X-Curve I'll try and explain I know it has to do with all speakers matching perf screen HF attenuation.
Antone-
Post by: Jaska Saarinen on April 08, 2009, 01:43:17 PM
... but I haven't ever before heard so much miss leading cinema technical information (at least not on pro audio sites)... all channel levels wrong... understanding THX role is wrong... and worst wrong information was this about x-curve...
"If you don't know about X-Curve I'll try and explain I know it has to do with all speakers matching perf screen HF attenuation."
Screen HF autenation don't have nothing to do with x-curve...nothing at all... X-curve was actually founded by Ioan Allen from Dolby Labs early 70's...he still works at Dolby.
I've done these approx. 25 years (also THX installer).
Post by: Scott Raymond on April 08, 2009, 03:18:05 PM
| Jaska Saarinen wrote on Wed, 08 April 2009 12:43 |
Sorry Antone, ... but I haven't ever before heard so much miss leading cinema technical information (at least not on pro audio sites)... all channel levels wrong... understanding THX role is wrong... and worst wrong information was this about x-curve... "If you don't know about X-Curve I'll try and explain I know it has to do with all speakers matching perf screen HF attenuation." Screen HF autenation don't have nothing to do with x-curve...nothing at all... X-curve was actually founded by Ioan Allen from Dolby Labs early 70's...he still works at Dolby. I've done these approx. 25 years (also THX installer). |
Here's a link to a good article on Cinema with history and some good info on the X-curve etc. Written by Loan Allen.
http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English _PDFs/Professional/Dolby_The%20X-Curve__SMPTE%20Journal.pdf
Jaska, have any of the newer processors provided for the capability of using something like Smaart? I ran into the wall on that as the Dolby CP500 was all self contained with pink noise and measurement mic connection built in. But I couldn't even use my M30 mic as the Dolby only provides 15 volt phantom. If there was a way to pick off the pink noise somewhere a person could at least use the Transfer Function for eq but back when this unit was made things like Smaart were a bit rare.
Post by: Jaska Saarinen on April 08, 2009, 04:10:19 PM
Post by: Jaska Saarinen on April 08, 2009, 04:17:57 PM
Post by: Phillip_Graham on April 08, 2009, 04:29:19 PM
| Antone Atmarama Bajor wrote on Wed, 08 April 2009 12:42 |
LFE are 95dB with 20dB of headroom for peaks. F and Surr are 85dB with 20dB of headroom. If you don't know about X-Curve I'll try and explain I know it has to do with all speakers matching perf screen HF attenuation. Antone- |
Antone,
Your channel levels are incorrect, as is your reason for the x-curve. Jaska below has things correct.
For a detailed discussion of the nature of the x-curve, please see:
http://www.rationalacoustics.com/forums/showthread.php?t=41
Post by: Jaska Saarinen on April 08, 2009, 04:37:45 PM
Unfortunatly Jamie and Calverton haven't done cinemas, but those fellows are great with Smaart, even so smart that they did bought it from EAW... even that Jamie has MeyerSound backrounds, before he went to EAW /Smaart...
Just read Scott link... try like last 5 or 6 pages... that's writen by the man who have greate x-curve... have nice reading..
Post by: Jaska Saarinen on April 08, 2009, 04:48:01 PM
Antone wrote:
"Your channel levels for THX are incorrect, as is your reason for the x-curve. Jaska below has things correct."
Post by: John Roberts {JR} on April 08, 2009, 05:17:17 PM
| Jaska Saarinen wrote on Wed, 08 April 2009 15:48 |
... forget to mention... THX don't have it's own levels... that's silliest thing what I have heard... THX is a quality standard, including how you should do your acoustics, sound isolation , viewing angles, etc....THX is not black box or a special system, it's just very well done system.... Antone wrote: "Your channel levels for THX are incorrect, as is your reason for the x-curve. Jaska below has things correct." |
Please work on keeping your quotes straight.. actually it was Phillip Graham who wrote to Antone saying you were correct.
Yup THX was somehow involved in equipment blessing/approval for THX theater use. I recall dealing with them related to getting some amps approved for cinema use. Some of their requirements seems unrelated to the task at hand, but I have much respect for Tomlinson Holman's earlier work at APT.
He seems to be up to a similar scheme with TMH approvals for home cinema.. I may start offering JR approvals for homebrew beer.
JR
Post by: Antone Atmarama Bajor on April 08, 2009, 06:12:06 PM
I have actually had a discussion with one of THX's testers, in their test room about the nature of screen attenuation, is it by any small coincidence that Perfscreen attenuation starts at about 2kHz and rolls off at 3dB per octave??? From the conversation I learned that some of the micro perf screens have a lighter roll off slope but they are not used as often.
I don't know all the details I worked with the man who took over at Skywalker after Tomlinson left. I don't know all the details but from what I gather, the x-curve is a result of the effects of room reflection and screen attenuation even if they didn't identify screen attenuation as part of the equation back then.
Can you imagine, how much power one needs to put in the top octaves to try and get flat response, from behind a perf screen. Most compression drivers can handle that level of power, and many that can suffer from terrible breakup modes, at those Levels.
I never had a discussion of tuning small and large rooms, but what Jerry used for tuning the B-Chain was a D2-unit (The successor of the R2-Unit) Which is a bunch of 1/3rd octave filters that sum, and uses a diamond pattern array of 4 countryman Mics with their own calibration files.
The 4 microphones are averaged together using a slow averaging method. That ensures that the reverberant characterstic in the room is picked up, and is part of the equalization process, and the room is equalized to the X-curve, with the reverb averaged in I don't think there is a big need for alternative slopes for larger rooms, but I could be wrong.
I've met a few of the Dolby guys but haven't really discussed cinema with them much.
I suppose my conclusion is although X-curve doesn't specifically mention or address screen attenuation, it is a result of behavior that seems consistent with the exhibition house environment. Which are all effected by things, such as room acoustics, and dimensions. As well as B chain devices, and to think that putting speakers behind a screen had no part in the equation seems like one is ignoring the elephant in the room, the screen is by no means acoustically transparent in the high frequencies.
If you removed the screen from the equation the X-curve would be quite different.
I also think that it can be argued that much of THX certified rooms and rooms since have much more aggressive, sound treatment then in the past so room reverberation is much less a problem to a point.
I don't think I've misinformed anyone thus far.
Except that I was 3dB off for Surround calibration settings.
The Dolby X-curve paper confirms the extra head room past calibration.
Can one argue that screen attenuation has noting to do with the characteristic roll off of xcurve?
Post by: Jens Brewer on April 08, 2009, 06:17:07 PM
| John Roberts {JR} wrote on Wed, 08 April 2009 17:17 |
I may start offering JR approvals for homebrew beer. |
Preliminary specs? Measurement hardware/software? More details JR.
Post by: John Roberts {JR} on April 08, 2009, 06:44:10 PM
| Jens Brewer wrote on Wed, 08 April 2009 17:17 | ||
Preliminary specs? Measurement hardware/software? More details JR. |
Actually I was just kidding... I don't encourage anybody to send or carry their inferior homebrew to Hickory.
In the words of Emily Litella, never mind...
JR
Post by: Scott Raymond on April 09, 2009, 06:24:02 AM
| Jaska Saarinen wrote on Wed, 08 April 2009 15:10 |
I use WinMLS, Smaart, Room-Capture... also Ivie IE-45 for some quick checks. When using Smaart type analyzing system I normally go in 6-ch external analog input (you need to have cable= 6 female XLR's and other end 25pin D connector) where I can play eighter Smaart (or similar analyzer) own generator or like NTI minirator... and after that you need to do just channel levels with using cinema processor internal pink noise generator: Left- Center- Right= 85dBC / each channel, left and right surround = 82dBC / each channel, analog (for optical sound) subwoofer same as center channel and when measured together (center+ sub) it looks +3dB LF area (summing)... and from that analog sub level raise digital subwoofer channel +10dB... practically this means in SLP meter C-weighting analog sub 79-81dBC and digital sub 89-91 dBC of course depending of subwoofer overall response... |
Thanks Jaska. Using the analog input is a good point that I hadn't considered. They'd gotten a DTS 6D with the purchase and the CAT 685 card was with it so wiring up a DB25 could have been an option and I'll keep that in mind if I need to do any more tweaking on it in the future. On a side note I find it somewhat interesting how the DTS audio comes off the CD(s) gets converted to analog, hits the 685, converts to digital, goes through the processor and then finally gets converted back to analog for the last time. But as the DTS process came later I'm assuming that was the only option as it had to be backward compatible with the older processors.
Post by: Antone Atmarama Bajor on April 09, 2009, 04:10:30 PM
I'm not sure that there is much difference between iso 2969 curve and x-curve as they both seem ~the same.
Perhaps some one here knows the difference.
But read page 4 here on this JBL paper.
http://www.jblpro.com/pub/technote/tn_v3n03.pdf
Post by: Scott Raymond on April 09, 2009, 06:59:39 PM
| Antone Atmarama Bajor wrote on Thu, 09 April 2009 15:10 |
I'm not sure that there is much difference between iso 2969 curve and x-curve as they both seem ~the same. Perhaps some one here knows the difference. But read page 4 here on this JBL paper. http://www.jblpro.com/pub/technote/tn_v3n03.pdf |
Antone,
In the Loan Allen link I posted above a fairly detailed description and history of the two starts at around page 16.
Post by: Antone Atmarama Bajor on April 09, 2009, 09:38:37 PM
I figured I should find a document that helped support my statements about the significance of screen attenuation, and the existing target response curves for cinema today.
I know that when a lot of the original tests and investigations were performed, that a majority of the test equipment, as well as reproduction equipment, was limited and not able to perform very well.
I think the technology finally started catching up to the standards in the 90's.
At least thats my opinion, not that the men and women at Dolby and the ISO and SMPTE teams didn't do great work with what they had available to them over the previous 50 or 60 years.
In modern cinema with some of the slow averaged room response tuning methods, I wonder how relevant some of the room size dependent response curves are. Those curves are from the early 80's when much test equipment was pretty questionable. It seems like they may have been going for a best guess with what the room reverberation will be like. I'll have to ask Jerry what he does, I've been around him when he's tuning rooms but I haven't done the deed.
I wonder if the Large room EQ curve is supposed to be as a result of more air attenuation of HF, or because room resonances will tend to be lower frequency in a larger room, so it is thought less HF energy is needed to feel balanced with the LF since the reverberant field gain isn't encroaching on the HF range?
Its all fun stuff. Theirs a lot of details involved in Cinema, and I'm only a grunt trying to learn as much as I can.
I want to go to a cinema with some Danley Super Subs, I'm tired of hearing the LFE Subs crap out on some of the rumble effects, that have been mastered into the film.
Antone-
Post by: John Roberts {JR} on April 09, 2009, 10:26:44 PM
I find Ioan's paper interesting since he calls the '70s the old days..
Here's a take from another Dolby Engr.. http://www.hometheaterhifi.com/volume_9_2/feature-article-cu rves-6-2002.html
In the early days frequency response was just one of the sharp knives they were juggling, as (HF) speakers got better, they started hearing wow and flutter and noise floor,,, Things we take for granted today.
JR
Post by: Scott Raymond on April 09, 2009, 11:12:00 PM
I'd big interested in experiencing Cinema with the Matterhorn sub.
I'd have to admit to a growing fascination with the Cinema environment. The history behind everything is good reading as well as some of the methods and studies they undertook to advance the realism of Cinema sound. It really reinforces how complex the interaction of audio and visual is in our noggens, even more so than the effects we run into in live audio. I haven't had time to read all the info Brian sent me, but have read some of the pertinent items several times and seem to pick new things out of it each time.