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Title: d&b B22
Post by: Helge A Bentsen on July 13, 2016, 03:07:38 pm
d&b launched the B22 earlier this year.
http://www.dbaudio.com/en/systems/details/b22-subwoofer.html

Similar specs to the old B2.
Anyone heard it and can comment on it's performace against the B2?
Title: Re: d&b B22
Post by: Josh Millward on July 13, 2016, 07:14:14 pm
Interesting...

I always wondered what the difference was between "normal" mode and "Infra" mode. I guess now I know!

That is one way to get the job done.

I, too, would be interested to hear the thoughts of someone who uses this product.
Title: Re: d&b B22
Post by: John L Nobile on July 13, 2016, 11:18:19 pm
Interesting specs in that the freq response is at - 5 db not - 3 or - 10. Also that the peak power has a time associated with it.
They're not exactly light but I think heavy is a good thing in a sub.
What's the price point?
Title: Re: d&b B22
Post by: Ivan Beaver on July 14, 2016, 06:59:15 am
Interesting specs in that the freq response is at - 5 db not - 3 or - 10.
At least with a graph you can determine what the -3 or -10dB points are.

Now whether that graph is processed or not (it has to be on the infra mode) is another question.

Seeing a processed graph is pretty much worthless, unless you ALSO see the processing applied to get that graph.

I do like the way EAW did things on some models.  They show the unprocessed (The only really useful graph in my opinion), the processing curve and the final/processed graph.

That way you have something useful to determine if the product might be right for you.

The PROBLEM with a processed graph, is that in many cases there is a good sized boost added to the low end of the subs.

When that happens, they are NO LONGER applying 1 watt or 2.83V at those freq.

So whatever boost has been added-that same amount of dB MUST be taken AWAY from the maximum output ratings-at those freq.  Because the  levels will not "scale" up

Lets say a speaker has a rated sensitivity of 100dB and a power capacity of 1000 watts.  Since 1000 watts is a 30 dB increase-the maximum level will be 130dB.

HOWEVER-if a 10dB boost is added at the low freq, then at those freq, you can only get a 20dB increase in level.

So lets say that 30Hz is -3dB down (with the boost applied).  So that is 97dB.  Add 20dB to that and you get 117dB-NOT 130dB.  BIG difference.

So if you are "expecting" to be able to get 130dB at 30Hz, you will be sadly disappointed after you let out the magic smoke.

It IS important to understand what is going on when looking at specs-they may not always be as you want to "believe" they are.

Simple numbers result in WRONG answers.
Title: Re: d&b B22
Post by: Helge A Bentsen on July 20, 2016, 04:54:01 pm
So it seems that no one has tried these yet?
Title: Re: d&b B22
Post by: Marjan Milosevic on July 21, 2016, 04:44:27 pm
I fail to see how this is classified as INFRA.
Title: Re: d&b B22
Post by: Samuel Rees on July 21, 2016, 10:56:01 pm
I fail to see how this is classified as INFRA.

In infra mode it is 32-68... isn't that 'pretty infra?'
Title: Re: d&b B22
Post by: Josh Millward on July 22, 2016, 09:26:19 am
In infra mode it is 32-68... isn't that 'pretty infra?'

I think the real point is that "Infra" mode does not actually extend the low frequency performance of the loudspeaker. It actually just reduces the more efficient high frequencies and pushes the LF cutoff down the slope a ways at the expense of maximum output.

Also, never mind anything below 30Hz... To me, when someone says "infra", I am not thinking 30Hz and up. I'm thinking 20Hz and below. Ergo, this sub does not really do "infra".

Title: Re: d&b B22
Post by: Will Cash on August 03, 2016, 08:41:33 pm
Anyone know the approximate cost?
Title: Re: d&b B22
Post by: Josh Millward on August 04, 2016, 09:41:04 am
Anyone know the approximate cost?

You know how that old saying goes, right?

"If you have to ask, you probably can't afford it."

Hahaha!!! I'm just kidding.

In reality though, I have no idea what it costs. I'm sure it will be plenty though, plus you are required to buy their amplifier/controller to go with it.
Title: Re: d&b B22
Post by: Will Cash on August 04, 2016, 10:26:03 am
Well if the cost is comparable to a TH118 I'm in the market...
Title: Re: d&b B22
Post by: Doug Fowler on August 04, 2016, 10:44:48 am
Well if the cost is comparable to a TH118 I'm in the market...

Are you sure about that?  You're prepared to buy the amplifier that goes with it?

Not one person commenting on this forum has seen it, let alone heard it, and you're "in the market"?
Title: Re: d&b B22
Post by: Will Cash on August 04, 2016, 10:49:17 am
No, I'm not sure, that's why I'm asking.

When d&b says "exclusively" for use with their amplifiers, this is truth, not suggestion?
Title: Re: d&b B22
Post by: Josh Millward on August 04, 2016, 10:57:38 am
No, I'm not sure, that's why I'm asking.

When d&b says "exclusively" for use with their amplifiers, this is truth, not suggestion?

All d&b loudspeakers are absolutely REQUIRED to be used exclusively (in the most literal sense of the word) with d&b amplifiers.

Quite simply, you do not ever use d&b loudspeakers without d&b amplifiers.
Title: Re: d&b B22
Post by: Will Cash on August 04, 2016, 11:21:17 am
10-4. Thanks for the clarification  8)
Title: Re: d&b B22
Post by: Helge A Bentsen on August 04, 2016, 01:51:45 pm
I noticed you get presets for some d&b speakers in X and Ottocanali amps from Powersoft. No idea if they are "official"


Sent from my iPhone using Tapatalk
Title: Re: d&b B22
Post by: brian maddox on August 04, 2016, 03:45:05 pm
All d&b loudspeakers are absolutely REQUIRED to be used exclusively (in the most literal sense of the word) with d&b amplifiers.

Quite simply, you do not ever use d&b loudspeakers without d&b amplifiers.

d&b manufacture remotely amped powered speaker systems;  an approach i frankly wholeheartedly endorse. 

Saying that you 'have to' use d&b amps with their speakers as though that were a bad thing fails to grasp the intent behind the system.  After all, you 'have to' use Meyer amplification with their boxes too. 

This annoying insistence on pairing manufacturer amplification and processing with speaker cabinets leads to a remarkable consistency in deployment.  Which means i can walk into any d&b rig anywhere and know exactly what i'm getting.  And that is a Very Good Thing.
Title: Re: d&b B22
Post by: Samuel Rees on August 04, 2016, 05:21:28 pm
d&b manufacture remotely amped powered speaker systems;  an approach i frankly wholeheartedly endorse. 

Saying that you 'have to' use d&b amps with their speakers as though that were a bad thing fails to grasp the intent behind the system.  After all, you 'have to' use Meyer amplification with their boxes too. 

This annoying insistence on pairing manufacturer amplification and processing with speaker cabinets leads to a remarkable consistency in deployment.  Which means i can walk into any d&b rig anywhere and know exactly what i'm getting.  And that is a Very Good Thing.

+1.
Title: Re: d&b B22
Post by: Jason Raboin on August 04, 2016, 05:24:16 pm
All d&b loudspeakers are absolutely REQUIRED to be used exclusively (in the most literal sense of the word) with d&b amplifiers.

Quite simply, you do not ever use d&b loudspeakers without d&b amplifiers.

Except the Max series of monitors.  Those require no processing and will work off any amp.
Title: Re: d&b B22
Post by: brian maddox on August 04, 2016, 09:07:36 pm
Except the Max series of monitors.  Those require no processing and will work off any amp.

Absolutely true.  Which kinda proves that d&b aren't making you buy their amps just to separate you from your money.

I kinda see them in the 'lab' with the MAX.  They're like, 'whoa, this sounds great out of the box without any special processing.  Should we tell anyone?'  :)

The fact that they did is kinda refreshing.
Title: Re: d&b B22
Post by: Scott Holtzman on August 04, 2016, 09:58:20 pm
d&b manufacture remotely amped powered speaker systems;  an approach i frankly wholeheartedly endorse. 

Saying that you 'have to' use d&b amps with their speakers as though that were a bad thing fails to grasp the intent behind the system.  After all, you 'have to' use Meyer amplification with their boxes too. 

This annoying insistence on pairing manufacturer amplification and processing with speaker cabinets leads to a remarkable consistency in deployment.  Which means i can walk into any d&b rig anywhere and know exactly what i'm getting.  And that is a Very Good Thing.

Vue Also has the processing and the amps in one package.

Title: Re: d&b B22
Post by: eric lenasbunt on September 27, 2016, 08:57:45 pm
The system approach is the way to go, not something to be complained about. Our Vertec rig sounds infinitely better on itechs with the system processing presets. You can't really even get them close trying to roll your own. Consistency and taking the guesswork out of setup for me and my engineers is well worth the premium for the system amps. 
Title: Re: d&b B22
Post by: Anton Tumas on October 03, 2016, 06:33:37 pm
Heard 12 of these at Burning Man this year! The setup was on the Mayan Warrior, which dominated this year big time. A 10 hang of V8 and V12 (2 at the bottom) and 12 of these bad boys flush-mounted inside the art car. They ran it a little louder than I like, but overall this was a super yummy system, my fav. that I heard. Better tuning than last year and they're now using D80 on everything.

Super clean and punchy, plenty of low end for house and techno (the only format played on this system). Night and day vs. B2 IMO, a big step forward.

These are rated 143dB in full space, so that's a 149dB of half-space output, which is kinda crazy to think about out of a dual-18 box. That's 4dB more than a B2 which ain't no slouch.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 14, 2016, 06:57:15 am
I am very curious at which frequency will that sub output 149 dB în 2pi space...
Probably WLS SPL ( when lightning strikes)
I played with 2 J sub and 2 J infra's on their amps and on Powersoft amps to hear the difference. Night and day!!! I am a fan of full system design like these, or KV2, Lacoustics,nexo,Danley  etc. But not on sub duty. Because most of the time, the setting is not suited for all music genres.
I've measured the subs oudoors with B&K 2270 with 4938-002 mic-preamp from the university I study and I got Lcpeak at 2 m of 145 dB from all of them at the same time ! So that would be 139 dB peak from single and around 136 dB Max RMS SPL. That is a measured number. I have always wondering where these companies take their numbers.
After that we decided to change the drivers inside with BC21DS115-8 on infra and 18SW115-8 on sub and then used the infra on K20 and the jsub on a K10,reinforced the enclosure after they broke appart and got 149 dB Lcpeak. And I promise you that I could keep that peak all day with a high crest factor.
I set up the device on Leq full spectrum on stupid bass heavy songs like Dullatron- Assassins on full 3 minutes I got 138 dB at 2 meters from those modified.
Title: Re: d&b B22
Post by: Kevin McDonough on November 14, 2016, 09:21:20 am
I am very curious at which frequency will that sub output 149 dB în 2pi space...
Probably WLS SPL ( when lightning strikes)
I played with 2 J sub and 2 J infra's on their amps and on Powersoft amps to hear the difference. Night and day!!! I am a fan of full system design like these, or KV2, Lacoustics,nexo,Danley  etc. But not on sub duty. Because most of the time, the setting is not suited for all music genres.
I've measured the subs oudoors with B&K 2270 with 4938-002 mic-preamp from the university I study and I got Lcpeak at 2 m of 145 dB from all of them at the same time ! So that would be 139 dB peak from single and around 136 dB Max RMS SPL. That is a measured number. I have always wondering where these companies take their numbers.
After that we decided to change the drivers inside with BC21DS115-8 on infra and 18SW115-8 on sub and then used the infra on K20 and the jsub on a K10,reinforced the enclosure after they broke appart and got 149 dB Lcpeak. And I promise you that I could keep that peak all day with a high crest factor.
I set up the device on Leq full spectrum on stupid bass heavy songs like Dullatron- Assassins on full 3 minutes I got 138 dB at 2 meters from those modified.


i wouldn't pay much attention to D&B's peak SPL numbers. They're great sounding products and the hire shop I do most of my freelance work for has switched over to D&B so I use V series on pretty much most of the work I do these days, but their max SPL numbers are always pretty much wishful thinking.

However outside of that, while its fun for us to play with these things on occasion trying to get to the maximum SPL possible and trying to squeeze every last db out of the sub isn't really the point.

As with all the major manufacturers, you don't want to pay all that money for a system that is used for professional hire work and then have to worry that if the music isn't of a high enough crest factor or some other factor isn't quite right you'll blow your drivers. You want them to be built proof and reliable, and work gig after gig and earn you money. I'm sure you probably could squeeze another few db out of the subs from d&b's range but the limiters and processing are set fairly conservatively to simply give good, undistorted sound and to prevent all but a major catastrophe damaging the driver and leading to repair bills. 

k
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 14, 2016, 10:26:34 am
Trying to squeeze the most out of anything is what I do. Why pay 6 subs instead of 4 and the amps necessary, when one with a good knowledge on how the drivers and amps behave can set limitter and compressors to have 3 dB more and still keep the sound clean and the drivers risk free?
Look at these for an instance
http://3s.lv/files/download/34
Same subs but with better drivers and amps (but half the price). The same idea I had but on a larger scale as they have their production line already.
Also why not paying enough attention to specs? If they say the go to 149 dB, they should. I know this is a matter over discussed here but it should be because it's a big problem. People like Anton Tumas from the previous post will believe what they write because he trusts them. If he is an event organizer he would choose that brand because when I go with a mammoth size FLH 60*60*30 dual 21 IPal that gets 144 dB SPL RMS   with an F3 of 28 hz and he reads that these subs go to 27 hz at 149 dB at half the dimensions he will choose him.so I would be forced to say a peak number where I would add 6 dB for the peak and another 3 from the sine mean and only then I would have a chance. I would have to lie because they lie...
Title: Re: d&b B22
Post by: Ivan Beaver on November 14, 2016, 12:01:25 pm

 max SPL numbers are always pretty much wishful thinking.


Max SPL numbers can mean VERY different things, and are often not what the user can actually get out of them.

1: Is the "Max SPL" some sort of average max-or a single peak in the response that gives a peak, but the overall level is lower?

I have seen this on quite a few products, and sometimes that "peak" in the response is 10dB louder than what the rest of the response can actually do.

On one particular sub model that peak is actually at 1,800 Hz.  Not exactly in the sub range-----------

HOWEVER-the cabinet CAN produce that peak so they are not lying, but they are NOT telling the user the "truth" as they would like it to be told to them.

2: The other peak is simply the maximum level on a short duration signal.  This is simply a misunderstanding of the user-not the manufacturer.

The problem is that normal SPL meters cannot read that peak (the integration time of the meter is to slow/long), so the user "thinks" that the speaker is not producing the level the spec sheet says.

YES the speaker is-but YOU don't have the proper tools to read it.  You need a PEAK response SPL meter (not fast or max).  The cheap meters simply are to slow.

3: Another is "What does it sound like at that SPL?".  In many cases the loudspeaker CAN produce a particular SPL, but it sounds so bad you don't want to listen to it at that SPL. 

Currently we don't have a spec of "Maximum listenable SPL".

That would be a VERY interesting spec and to see how it is applied, if it ever happens-I doubt it.

If you have a good peak reading SPL meter, you can measure the same signal at the same location,  and get measurements that are 30dB or more different.

They are all correct-for the particular weighting and time applied to them.

Loudness is NOT a simple thing
Title: Re: d&b B22
Post by: Nathan Riddle on November 14, 2016, 01:41:14 pm
Currently we don't have a spec of "Maximum listenable SPL".

Couldn't that spec be a simple, xxx.x average spl @ 10m on type 1/0 meter in a field with closest object > 100m away while maintaining less than 10% (Arbitrary*) total average distortion?

*find out what is an acceptable distortion % to an average group of people. I think 10% is pretty horrid so...yeah; Could also be changed per octave too?

I would find those type of specs vastly more useful than the specs most devices currently employ. It would work for subs & mains and would tell us how a certain speaker compares to others.

Perhaps you should speak to the marketing folks and employ a vastly superior ONE NUMBER EVALUATION SPEC, echo....echo........echo...  :P
Title: Re: d&b B22
Post by: Ivan Beaver on November 14, 2016, 05:23:06 pm
Couldn't that spec be a simple, xxx.x average spl @ 10m on type 1/0 meter in a field with closest object > 100m away while maintaining less than 10% (Arbitrary*) total average distortion?

*find out what is an acceptable distortion % to an average group of people. I think 10% is pretty horrid so...yeah; Could also be changed per octave too?

I would find those type of specs vastly more useful than the specs most devices currently employ. It would work for subs & mains and would tell us how a certain speaker compares to others.

Perhaps you should speak to the marketing folks and employ a vastly superior ONE NUMBER EVALUATION SPEC, echo....echo........echo...  :P
And you run into the same issues as "Peak SPL"

Is that distortion at on e ONE freq?

Or an average across the band?

How do you do the average?  Is it by freq or octave?  How much smoothing is allowed?

What IS the operating band? 20-20K or the claimed -3dB points on the spec sheet?

It could get quite interesting how different people "interpret" the spec and use the "holes" to their advantage.

And if you are talking about SPL at that distortion-the same issue could come back up.  What if some freq that are low in distortion actually boosted to get a higher SPL rating-even though the freq response would not be good?

I could see something like "tuned for maximum undistorted output"  Which means it sounds like crap, but at some freq it is clean and meets the "measurement parameters.

How do you measure that SPL?  Using what type of meter/response etc.

Once you start digging into it, it gets pretty complicated pretty quick.

Trying to come up with a single number for a VERY complicated subject is NOT easy.  And would be full of misinterpretations of the "rules".
Title: Re: d&b B22
Post by: Nathan Riddle on November 15, 2016, 11:40:51 am
And you run into the same issues as "Peak SPL"

Is that distortion at on e ONE freq?

Or an average across the band?

How do you do the average?  Is it by freq or octave?  How much smoothing is allowed?

What IS the operating band? 20-20K or the claimed -3dB points on the spec sheet?

It could get quite interesting how different people "interpret" the spec and use the "holes" to their advantage.

Once you start digging into it, it gets pretty complicated pretty quick.

Trying to come up with a single number for a VERY complicated subject is NOT easy.  And would be full of misinterpretations of the "rules".

Haha, Ivan you're the best! I was trying to be a bit tongue in cheek.

Very good points, especially the ones about people using the 'holes' in the rules to their advantage to get a vastly superior one number spec.

Though, I'd like to believe the more reputable manufactures wouldn't try to do such a thing. and stick within the intent of the distortion spec.

A thought: just like SPL, Impedance, and Phase would a distortion graph work well?
Title: Re: d&b B22
Post by: Ivan Beaver on November 15, 2016, 04:53:57 pm


Though, I'd like to believe the more reputable manufactures wouldn't try to do such a thing. and stick within the intent of the distortion spec.


You might be surprised.

Some of the biggest and most respected "players" are the ones that "misuse" the specs the most.

But they get a "free pass" because of who they are and nobody would suspect them.

OF course, it all "comes to light" during a side by side listening.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 16, 2016, 12:29:54 am
There are ways to measure output with distortions included.
CEA Max burst is a way.
It's a way of getting the max output at any frequency given, without passing a threshold.
Data-Bass.com is a page where one can find this sort of tests using 2 meters ground plane RMS SPL so one should add 9 dB for peak 1 m output.
Title: Re: d&b B22
Post by: Ivan Beaver on November 16, 2016, 06:10:49 am
There are ways to measure output with distortions included.
CEA Max burst is a way.
It's a way of getting the max output at any frequency given, without passing a threshold.
Data-Bass.com is a page where one can find this sort of tests using 2 meters ground plane RMS SPL so one should add 9 dB for peak 1 m output.
I wonder where the "9dB" comes from.

If the signal has a 6dB crest factor, and the distance is 2M away (6dB from 1M), that would be 12dB, not 9.

With most speakers that are of a decent size measuring at 1 or 2M is simply not far enough away to get any sort of useful information regarding how loud that speaker will be at a distance.

With some cabinets, a 1 or 2M distance will give a higher number than you would experience if you were to use that number and figure out at a distance.

With other cabinets it will give a lower number than you would get at a distance.

To me-the whole purpose of the "1M" SPL has NOTHING to do with how loud it is is at 1M (nobody is actually that close), but rather is a number that is used in figuring out how far it would be at a distance.

That is why in many cases it is better to measure at 10M, so you "get rid" of any close measurement errors that would skew the whole purpose

If I am not mistaken, the CEA test is mainly for home theater purposes/users.  So the 2M distance would be better suited for that setup.

So it becomes important to use a proper test for the proper usages.

There are all sorts of "tests" that can be done, but if they don't provide useful information, or cannot be compared to devices measured others ways, they are not real useful.

At least that is my opinion
Title: Re: d&b B22
Post by: Mark Wilkinson on November 16, 2016, 08:30:38 am
I wonder where the "9dB" comes from.

If the signal has a 6dB crest factor, and the distance is 2M away (6dB from 1M), that would be 12dB, not 9.



Hi Ivan, swept sine waves, so a 3db crest factor.
Title: Re: d&b B22
Post by: Ivan Beaver on November 16, 2016, 08:49:50 am
Hi Ivan, swept sine waves, so a 3db crest factor.
But if you are adding 3dB because it is a sine wave-then you can also just add 3dB to other SPL specs as well.

I don't know of anybody (at least in legit speaker specs) who uses the "3dB crest factor of a sine wave" and adds that to SPL reading.

Sorry-but that makes no practical sense to me

If you wanted to start "playing that game", then we should just go ahead and rate all loudspeakers as twice their power capacity.

 It doesn't make them any louder, but gives a false sense of output and power capability based on a spec that is essentially "useless"-at least as far as I am concerned.

But that is just my opinion-----
Title: Re: d&b B22
Post by: Mark Wilkinson on November 16, 2016, 12:29:19 pm
But if you are adding 3dB because it is a sine wave-then you can also just add 3dB to other SPL specs as well.

I don't know of anybody (at least in legit speaker specs) who uses the "3dB crest factor of a sine wave" and adds that to SPL reading.

Sorry-but that makes no practical sense to me

If you wanted to start "playing that game", then we should just go ahead and rate all loudspeakers as twice their power capacity.

 It doesn't make them any louder, but gives a false sense of output and power capability based on a spec that is essentially "useless"-at least as far as I am concerned.

But that is just my opinion-----

Ivan, I find great value in the data-bass specs.

I mean, take your specs which have much better disclosure than industry average. The TH-118 shows:  Max Output  137dBSPL/143DBSPL.
Are those max output specs measured, or just calculated from measured sensitivity and extrapolated off OEM driver power-handling?
If measured (hooray!)  Do you use 6dB crest pink? ... for the 6dB diff in specs?
Or do you use sine sweeps as in the sensitivity curves you show?
If using either sine sweeps for max output or simply not measured, what's the basis for the 6dB spread?
And will 137dB hold without compression? And at what distortion level?

So for me, data-bass (and also Production Partner), provide VERY useful info that goes way beyond anything else I can find.....as both offer distortion and compression data.
Without this data, max output specs are basically hokey IMHO..especially "peak" marketing speak.

Distortion tests of course require sine waves with their inherent 3dB crest.
I can easily see Jeff wanting to equalize a data-bass CEA "peak" vs the usual +6dB add on that's just on top of others' most likely simply calculated max output. Especially since data-bass is showing actual measured peaks at given distortion levels....

Both data-bass and Production Partner also provide very good detail into actual testing methodology..best data for the informed purchaser I know of...

Do folks know other good sites that provide distortion and compression tests?




Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 16, 2016, 01:28:21 pm
From real measurements made in free space with sine waves and also EIAJ and CEA burst signals and also full spectrum pink noise I can tell you for sure that the output DSL specifies in the Direct program on Continuous and Program settings correlates very well with the measurements. So one can get about 134 dB RMS sine at 55 hz and the power compression is around 2,5-3 dB and with CEA Bursts and pink noise I can get 137 dB . The Lcpeak measurement gave me 142 dB and never more from single even trying with a LabGruppen FP14000 bridged  so 14000 Kw peaks. I have used a high pass filter at 125 hz so no sounds over the could get the results higher.
At around 3800 watts applied for 2-3 seconds at a time to obtain the RMS value, i can tell you it is 134  dB  continuous output, but not for long :) anyway, the 18SW115 driver can thermally take about 950 Wh to get to a raise of +40° from 25 to 65 and then stabilize (in this enclosure where in the pass band you have an AVERAGE of about 15% efficiency) . More than that and you can destroy it. But that means one can use a signal with around 6-8 dB crest factor and be safe and also have usable 137 dB peaks.

Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 16, 2016, 01:35:29 pm
I don't think it matters if the standard is for cinema, outside, inside etc as long as it provides a useful and real insight of the performance of a given system. 2 m is a good distance for these kind of measurements and he made tests regarding this procedure. The measurements made at 2 and further than 2 meters were practically identical. ( but not theoretically, but the differences were smaller than temperature and humidity differences so no need to overkill. Also he obtained a better  signal to noise ratio when closer)
His methods are extremely useful, found to the absolute limits and also saying where they are better to be used.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 16, 2016, 01:58:13 pm
I fail to see how this is classified as INFRA.
Probably because most of the people have never really heard bass under 38 hz (comparatively with the rest of the spectrum) at full power and when they use a stack of 12 subs with that response curve (look at that response curve!!) that would probably generate over 132 dB at 30 hz at 10 meters, they will all concur it is a infra sub. Because of the rest of the response will be lower than under 40 hz, they will perceive them as being deeper in response.
Once one will let them to go flat up to 80 hz then all the infra sensation will disappear. Put any sub even with 6 dB more and an f3 of 23 hz but equalized to be flat to 80 hz and most people will say the D&B goes deeper .
There are many designs that will go lower and with more output under 30 hz than this sub but most of the designers are using them on more than one octave so these will be the Infra's .
I wonder how well they integrate them with their tops. I heard some complete systems here in Romania on several occasions and I always liked them. But I only tested and measured the JSub and JInfra without tops.
Title: Re: d&b B22
Post by: Marjan Milosevic on November 16, 2016, 04:22:13 pm
I was with the crew doing a Prodigy concert this summer.
Main rig was EAW Anya 16 per side and 24 Otto subs.
Prodigy tours with their own set of 8 D&B J infras that was added to the system and used on an aux as a complimentary infra effect in some of the songs.
I was watching the laptop that was monitoring the system response live using Smaart.
I was very curious to see what the added 8 J inras will look and how low they will go during those short times they were used.
I got really surprised when i saw that J-infra added a lot of 38Hz content in a very narrow peak.
Nothing really infra there. it only boosted the low end for like 4-5db for a very short periods and that was it.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 16, 2016, 05:33:52 pm
I have listened to the Otto and Anya (18 subs and 36 speakers) and MAN those speakers sound sweet!!!!! On their own they can get very low with brute force and those subs despite not being crushingly powerful, they are clean and gets 25 hz with power.
(http://uploads.tapatalk-cdn.com/20161116/59171a8e4d065982e03a9c8753168175.jpg)
(http://uploads.tapatalk-cdn.com/20161116/23e695b51deadecfdd0fa7981b4d7d90.jpg)
It was set for a video mapping contest on our biggest building and the content was mostly music with movie effects
Title: Re: d&b B22
Post by: Helge A Bentsen on November 16, 2016, 07:45:47 pm
Otto walks all over the B2/22/J-infra but it has a hefty price tag.


Sent from my iPhone using Tapatalk
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 17, 2016, 03:45:08 am


So for me, data-bass (and also Production Partner), provide VERY useful info that goes way beyond anything else I can find..

Both data-bass and Production Partner also provide very good detail into actual testing methodology..best data for the informed purchaser I know of...

Production Partner has some of the most thoroughly and useful measurements and tests publicly on the web . The tests for the JBL , L-acoustics, LabGruppen and especially Powersoft X4-8 are top notch. I hope they will keep doing this for more products.
I would like to see tests for products like the Martin Audio MLX , D&B J series, Nexo, Danley Jericho and BC415, EAW Anya, amplifiers like Crown, Powersoft K series, Linea Research, QSC,Speakerpower :) asking too much?
Title: Re: d&b B22
Post by: Marjan Milosevic on November 17, 2016, 11:07:02 am
Mircea, that is the exact system i am talking about. We were discussing a lot about it with the EAW engineer that was with us on site. I even had the opportunity to peek inside the OTTO. So i am not at all surprised with the Helge comment :-)
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 17, 2016, 11:28:18 am
Mircea, that is the exact system i am talking about. We were discussing a lot about it with the EAW engineer that was with us on site. I even had the opportunity to peek inside the OTTO. So i am not at all surprised with the Helge comment :-)
Oh boy. What I would give to know what driver is inside. I thought it's the 18TBW 100 and with some digimod amps.;)
The at they used a bandpass enclosure is smart. I simmed and the driver behavior is not optimised on a Bass Reflex of these dimensions but if one puts a band pass port in front of the driver it can be very good for the way the driver behaves. I calculated a potential output and it isn't higher than 132 per enclosure but that is with those drivers....
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 17, 2016, 11:31:55 am
I tried to talk wit some engineers there but I was with my girlfriend and I couldn't go missing for such a long time because there was more than 60K people there :(
Title: Re: d&b B22
Post by: Marjan Milosevic on November 17, 2016, 12:06:52 pm
Nothing in the Anya/Otto is B&C. Sorry i can not say more.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 17, 2016, 12:30:39 pm
The 15 in the anya is definitely B&C 15SW115 !
(http://uploads.tapatalk-cdn.com/20161117/18189c9187c14506de35f3f5c5749e8b.jpg)
Title: Re: d&b B22
Post by: Josh Ricci on November 17, 2016, 12:58:42 pm
I wonder where the "9dB" comes from.

If the signal has a 6dB crest factor, and the distance is 2M away (6dB from 1M), that would be 12dB, not 9.

With most speakers that are of a decent size measuring at 1 or 2M is simply not far enough away to get any sort of useful information regarding how loud that speaker will be at a distance.

With some cabinets, a 1 or 2M distance will give a higher number than you would experience if you were to use that number and figure out at a distance.

With other cabinets it will give a lower number than you would get at a distance.

To me-the whole purpose of the "1M" SPL has NOTHING to do with how loud it is is at 1M (nobody is actually that close), but rather is a number that is used in figuring out how far it would be at a distance.

That is why in many cases it is better to measure at 10M, so you "get rid" of any close measurement errors that would skew the whole purpose

If I am not mistaken, the CEA test is mainly for home theater purposes/users.  So the 2M distance would be better suited for that setup.

So it becomes important to use a proper test for the proper usages.

There are all sorts of "tests" that can be done, but if they don't provide useful information, or cannot be compared to devices measured others ways, they are not real useful.

At least that is my opinion

Ivan,

The 9dB issue is from comparing a 1m measurement to a 2 meter one. (6dB there)
The other 3dB is the difference from reporting a "peak" SPL from the waveform and an "RMS" SPL. Note that the speaker output or waveform has not changed. Only the method of reporting the output. This is explained in the CEA-2010 section below. Also note that a lot of places or manufacturers are reporting a 1m half-space "peak" output. That's not what I do at Data-Bass I use a much more conservative and IMO more realistic 2 meter half-space (1m full-space) SPL reported from the "rms" method of analysis of the waveform.

I'll just paste the testing methodology from Data-Bass here. I'm the guy behind it. In my opinion there is solid logic behind the way things are done that makes sense from a practical standpoint as far as actually completing the testing and displaying useful data. Is it perfect of course not, but it's a more complete picture and higher resolution than the measurements from almost anywhere else. IMHO of course. It's also extremely time consuming and very unforgiving and/or unflattering to the DUT.

Equipment used:
•DAW desktop with Win pro 64 bit
•2 ND9 spl calibrators
•Quest QC-10 SPL calibrator
•ACO Pacific 511E SPL calibrator (#011010)with Q1,Q3 & Q7 adapters
•matched pair of Earthworks M30 measurement microphones with windscreens (#1764 & 1766)
•ACO Pacific:
PS9200 power supply with 50volt modification (#9818) ◦4012 preamp (#98187-3)
◦7012 mic capsule (#21720)
◦7047 mic capsule, G.R.A.S. 40AM mic capsule
◦WS-1 windscreen
◦4212 preamp
◦4048 preamp
◦PSIEPE-4

•Smith & Larson Woofer Tester 2
•Presonus Firebox microphone preamp interfaces
•Behringer DCX2496
•Symetrix 511E
•Powersoft Digam K10 (Klein & Hummel KPA-2400) amplifiers
•Powersoft K20-DSP+AESOP amplifiers
•Speakerpower SP2-12000 amplifier
•Ideal Industries 61-702 DMM
•LinearX VI Box.


Software:
•ARTA
•STEPS
•LIMP
•REW v5
•Spectrum Lab
•RplusD
•NCH tone generator
•CEA2010


The Firebox without compensation is +/-0.5db between 10hz and 20khz. The PS9200 powersupply and 4012 pre-amp are +/-0.5db between 10hz and 20khz. The M30 and ACO 7012 microphones are within +/-0.5db tolerance from 10hz to 20khz or better. The Behringer DCX2496 is measured flat within +/-0.5db from 7-19khz. The Powersoft Digam K10/Klein & Hummel KPA-2400 amplifiers and K20-DSP amplifiers measure +/-0.8db 10-22khz, Speakerpower SP2-12000 amplifiers are +/-0.5db 5-20khz or better. The total signal chain should be within +/-1db from 10 to 15khz. This is good enough for reasonable accuracy in the primary range of interest for subwoofers, 10-200hz.

Measurements:

For drivers the tests start with a measurement of the drivers small signal parameters (TSP's) and generation of a free air impedance plot using LIMP software or occasionally a Smith and Larson Woofer tester 2. The drivers get a brief breaking in with pink noise and sine waves in free air, while doing a check for proper driver function prior to the measurements. Afterward another impedance measurement is taken with the driver/s loaded into the enclosure to be tested. The parameters collected will often vary somewhat from the manufacturers specs. The results depend heavily on the test methods and setup used. Additionally after discussion with several very well known and respected driver manufacturers a variation of up to 25% in some parameters is considered acceptable. Also many parameters are easily affected by the environmental conditions, most notably the suspension stiffness. The added mass method is used to lower the FS of the system the required amount to calculate the parameters. This is accomplished using 6.5 gram ceramic magnets clamped through the driver cone. This method is much more accurate in our experience than the known air volume "test box" method, but is still prone to some error. Ideally mms of the driver would be directly measured by weighing the assembly but this requires access to the parts themselves or cutting up a driver for this purpose. Typically this is not feasible so the added mass method is used. The impedance curve is often overlooked by many in favor of other more "exciting measurements, but the impedance measurement along with a few other facts about the driver or system can often give a lot of information and insight into how the system will behave. For example when looking at large subwoofer drivers the "Q" and magnitude of the impedance peak can offer insight into how strong the motor system is, the placement of the peak/s can indicate the FS of the driver or the tuning of the driver/enclosure system, the damping of the system can be hinted at and small anomalies in the upper part of the impedance curve can indicate resonances or vibration issues in the cone, frame, enclosure or port. With large subwoofer drivers if the impedance rapidly rises back up after the impedance peak this typically indicates a large amount of inductance in the motor system and a rolled of upper bass spectrum with diminished sensitivity.

Then on to the outdoor ground plane testing. The systems are placed on the ground out in a large field with the nearest large objects being 60ft or more away and the microphone is placed pointing at the subwoofer at a distance of 2 meters from the nearest enclosure edge or face. In this manner the effects of any boundary's or room acoustics can be eliminated leaving the response of the speaker minus the influence of any strong reflections. In a typical room the interaction between the boundary's and the radiation of the system being tested will serve to completely obscure the raw response of the unit and measurements taken in such an environment could only be compared to other measurements taken in this same space. Subs having multiple radiation sources will be placed so that the driver is closest to the microphone or equidistant in the case of multiple drivers and any ports, pr's or other radiators will be placed as close to the microphone as the cabinet geometry allows. All measurements are taken at a distance of 2 meters from the DUT unless otherwise specifically noted for the measurement. Systems having multiple radiation points or having drivers firing from 2 or 3 opposing enclosure faces will have measurements taken at a distance of 10m's and 2m's and used to develop a compensation file in order to properly compare the output power of these systems with conventional direct forward radiating systems. Outdoor ground-plane measurements are what is considered to be half-space and impart 6dB of gain from the single boundary's reinforcement when compared to an anechoic free-space measurement taken from the same distance. Increasing the microphone distance from 1 meters back to 2 meters conveniently reduces the SPL by 6dB back to a level equivalent to a 1m anechoic or free-space measurement. It also has the added effect of allowing all of the radiation from a system that may have multiple radiation points to blend better at the microphone. With many larger sub systems the enclosure itself is large enough and the distance between radiation elements is large enough that the system itself is providing some loading to the output of the system delivered to a microphone at only 1m distance. Effectively it could still be in a quasi near-field environment. Also the distance between radiation points on the system may be large enough to account for a significant percentage of the 1m distance which will misrepresent the total output makeup of the system by exaggerating the output of the closest radiator and under representing the output of those further away relative to each other. Some extremely large systems can still exhibit some effect at 2 meters. For these reasons the standard distance used is 2 meters and not 1m as it represents too many compromises for larger systems.

Test Procedure

1. A raw 1 watt (nominal fixed voltage)/1 meter response measurement with no signal shaping. This test is only performed on passive systems. (Note: Originally this test involved 1w maximum input power calculated using the impedance measurement taken of the driver/s in the enclosure. The minimum impedance measured in the subs intended pass band was used to calculate what voltage input will generate 1w of power into the load at the minimum impedance point. This limits the DUT to receiving no more than 1 watt of power at any point in the intended frequency range of use. Other methods of using a fixed voltage such as 2.83v without regard for the enclosures complex impedance profile can lead to apparent advantages for lower impedance cabinets as they will in reality be receiving higher power during the measurement but does not account for the fact that the maximum voltage available from an amplifier into the lower impedance is usually less. The method used here we believe represents a better indicator of true efficiency and some indication of how difficult of a load the speaker will present to an amplifier. However this resulted in odd voltages being used like 1.8v, 3v, etc...After being asked multiple times to standardize the voltages it was decided to settle on voltages of 1 volt for 1ohm systems, 1.41 volts for 2 ohm, 2 volts for 4 ohm, 2.83 volts for 8ohm and 4 volts for 16ohm systems. The impedance of the systems is still determined by looking at the minimum impedance measured between 10 and 200hz. Whichever range the minimum impedance of the system is closer to dictates what type of impedance it will be considered. For example a system with a Z min of 1.3 ohms would be considered a 1ohm system not a 2ohm system. A system with a Z min of 6 ohms would receive 2.83 volts and be considered an 8 ohm system, but one with a Z min of 4.8 ohms would be considered a 4 ohm system. In this way it prevents inflated sensitivity ratings by testing 2 ohm systems with a full 2.83 volts for example. Obviously this is not perfect but by looking at the measured data and the voltage supplied one can calculate what the system would measure at a different voltage input anyway.) The results of this type of measurement give insight into how loud the system will be with a specified input voltage and in conjunction with the impedance measurement can give an idea of system efficiency and how heavy of a load the speaker is on the amplifier driving it. Bear in mind that this does not indicate necessarily which system will be louder as that also depends on compression effects, thermal heating and driver excursion limits. It does however allow you to calculate the maximum potential output with a specific amount of amplifier voltage.

2. A raw 100 watt nominal(10x the 1 meter voltage) / 10 meter response measurement with no signal shaping. The voltage is increased by 10X over what was used for the 1w/1m sensitivity test and the microphone is moved back to a 10 meter distance. This is to get a look at the response shape at a greater distance where the effects of a large baffle or enclosure, or widely spaced radiation points on the system response should be mitigated and the power is increased to a higher level, which could start indicating some compression or variation on the FR in some less robust systems. This also gives a glimpse at far field performance if the speaker is intended for use in large spaces at high volume and allows for far better integration of the output of systems having multiple radiators. This test is also only performed on passive systems. This measurement should be examined just as the 1 meter sensitivity measurement and in fact comparison of the two measurements from different distances is often helpful to gauge near-field effects from the proximity of the DUT to the microphone at a 1m or 2m distance. In general the 10 meter higher power sensitivity measurement is found more useful and accurate to describe the system behavior because of this.

3. Basic frequency response shape. With powered or complete active subwoofer systems the response will be measured with a variety of different settings in order to gauge the effectiveness of the on board controls. Typically this would involve various settings of the low pass filter, a few different settings of any internal EQ bands available, all preset response curves available, damping settings, different modes of operation, plugged ports, sealed/vented, etc...A combination of settings will then be selected as the "basic response" to be used for the rest of the measurements. Typically the subwoofer will be configured for whatever response shape is widest bandwidth at the top of its frequency range and for whatever deep bass response appears to be most natural and unequalized without heavy low frequency boost. This is done because EQ eats up amplifier quickly and if done in the deep bass as is common it will also eat up driver excursion quickly. This will cause the maximum output measurements to be limited very early, by the deepest bass, wherever the EQ boost is heaviest and this will result in the testing being stopped before the unit is pushed very hard in the upper parts of it's bandwidth. Ideally we want to see what the DUT is capable of full bandwidth and not just limited to a small frequency band. Once these settings are settled on the basic response of the DUT as it will be set for all future measurements will be captured over a 10-200Hz bandwidth. In most cases an extended range frequency response was measured to see the response well past 200hz as well. Active systems typically are filtered not much past 300hz or so, but passive systems will be run without any top end limiting so they will be measured up higher in frequency to get an idea of the drivers potential capabilities and issues in the mid-bass. Passive units will be measured sans any processing at all and will also be measured with a suitable protective high pass filter applied if it is required. If so both responses will be shown for comparative purposes.

4. Impedance measurement. (For passive systems only.) LIMP software is used to measure the impedance of the system (A voltage of about 1 to 2 volts is used typically.). This can then be compared against the raw driver impedance measurements and the impedance measurement of other drivers tested in the same enclosure. The impedance measurement is very useful for identifying resonances or vibrations in the system, gauging how close the real system is to any simulated performance and calculating how much actual current or power is being applied at a certain voltage input. It can also help identify the tuning of helmholtz resonator systems and the Fb of horns.

5. Long term output compression sweeps. After setting the DUT's output level to correspond to an output of 90dB at 50Hz at a 2m distance using a 50hz sine wave signal, the response is measured using an ascending 0-120hz sine wave sweep of 24 second duration. This is the base measurement and output level which output compression is gauged against. Then measurement sweeps are taken back to back while the input signal is progressively increased by an amount that should cause the DUT to produce 5dB greater output each time up to the point where the DUT starts compressing the output in an obvious manner by 3dB or more, or starts to emit distress noises. Typically the final loudest sweep measurement will only be increased by 2 or 3 dB as the DUT is already showing signs of reaching its limits and a further 5dB increase in output is simply too much to ask. After the loudest measurement is completed the input signal will be adjusted back down to the starting 90dB at 50Hz base level and recaptured and compared to the first "cold" 90dB measurement. This shows the effects of long term heating in the driver voice coil/s and motor/s. 2 types of graphs are generated from this test set. The basic overlay of each sweep which will show how the response changes with each increase in level and another graph which shows only the amount of compression that is occurring in the systems output referenced to the initial 90dB "cold" measurement. Ideally what you are looking for is the least amount of compression throughout the entire bandwidth at the highest sweep levels.

6. THD and distortion by component measurements are captured using long duration 256K, 8000z SR sine sweeps generated by ARTA software, starting at a level corresponding with the lowest output level used in the power compression tests (90dB @ 50Hz @ 2 meters) and is increased by increments of 5db for each measurement from there mirroring the levels used during the long term output compression sweeps. The relatively high level of background noise present at the test site has some effect on the lower volume measurements accuracy especially in the deep bass below 20Hz where most systems will have output well down into the background noise floor at the more modest drive levels. Distortion is usually low enough at lower volume outputs to not worry about to begin with, so the data for only the 3 or 4 highest output levels is presented for most systems. When considering distortion of the signal by the loudspeaker obviously the lower the amount the better but there are other considerations to look for such as the harmonic make-up. Generally a good result is a system that has low distortion even at very large outputs and has a distortion profile that does not have abrupt changes in distortion magnitude as these typically indicate other things about the system such as a severe resonance and that it may be more audible. Also when considering the harmonic makeup of the distortion the general guideline is that the lower order and even order harmonics are less offensive than the odd and higher order harmonics. Odd order harmonics do not blend in with the fundamental in a pleasing manner like even order harmonics do so they tend to stand out more. For example a sub with 12% 2nd harmonic distortion probably won't sound bad at all, but a sub with 12% 5th harmonic distortion would be much more obviously heavily distorted to your ear and "wrong" or "overdriven" sounding. 2nd harmonic distortion can be quite high indeed and the bass system can still sound perfectly acceptable or even good. Large amounts of bass frequency H2 are rather hard to hear with the rest of the frequency bandwidth included. The 3rd harmonic or H3 is higher in frequency and is an odd order harmonic so it is a little more offensive but it still takes quite a large amount of H3 distortion to make the bass sound obviously distorted or bad. The 4th harmonic is a little more easy to notice since it is now typically going to fall well outside of the bass range and sound like something your bass system should not be producing, but typically 4th harmonic distortion in bass systems is typically well down in level compared to the 2nd and 3rd harmonics which dominate usually. Once you get to the 5th harmonic and higher it takes much less of a percentage of the output to become audible. Thankfully most bass systems do not output large amounts of harmonics that high up in band unless they are severely overdriven or have other issues.

7. Spectral contamination was tested at various drive levels using a 10 tone equally spaced sine excitation centered between 20 and 77hz to test the amount of self noise each DUT generates. This type of test is very rough on the system as the driver and amplifier both run into overload much quicker than would be expected. The base level was 90db total and the level was increased by a nominal 5db until there were obvious overload or distress noises. Ideally what you would see with this test is nothing other than the 10 sine tones used indicating a very clean output. Distortion and spurious noises would start to show up in between the center frequencies of this test on the resulting graph. A cleaner more powerful result would have sharper defined center frequencies and deeper notches in between the center frequencies at higher output levels indicating a much cleaner more accurate reproduction of a very tough signal. (This test has been discontinued. It was difficult to setup, very rough on the systems at louder output levels and more importantly it did not seem to give much useful information that could not be gleaned from the other standard output and distortion tests already.)

8. Maximum long term output is derived from the highest sweep level attained during the long term output compression testing. This is the highest long term sustained level attainable by the DUT within it's entire intended bandwidth, at which point some limiting condition whether amplifier, or excessive: excursion, noise, compression or distortion is in evidence in some part or all of the frequency range. (Note this does not mean that the subwoofer will handle a 100% duty cycle sine wave at this power level indefinitely! It will not!) The long term output compression test is meant to simulate the effects of high duty cycle use on the system but in a much more rapid manner. The long duration sine wave sweeps at the highest power levels are brutal on the systems and are meant to simulate many hours of playback of typical material with a MUCH lower duty cycle. Sine waves are 100% duty cycle so the voice coil gets heated relentlessly and in fact this test type kills more drivers than any other. Heavily compressed electronic music is only 25% duty cycle at most and typical music is far less than that so the average power is far less than that of the test signals used here. Therefore the voice coil and amplifier have some "downtime" to recharge and cool off a bit. Don't think of this measurement as output that can be sustained indefinitely...Think of it as a survival point...The sine wave test signals may generate and average power of 1500w from the amplifier into a system. Actual music or movie content that produces peak outputs of the same SPL levels might require the same amount of peak power but the average power seen over the same time period is more likely to be 200 watts than anywhere near the 1500 of the sine wave.

9. CEA2010 maximum short term distortion limited output. Maximum RMS short term output is measured at 2m ground plane. This test involved short 6.5cycle duration shaped sine bursts centered at 1/3rd octave intervals of 20, 25, 31.5, 40, 50 and 63hz. Additionally further test frequencies have been added at both ends of the spectrum (10, 12.5, 16, 80, 100 and 125hz) to better represent more of the full bass bandwidth as long as the systems were capable of reproducing meaningful output in those bands. The DUT's output level is then increased while the distortion is monitored until either the DUT stops gaining in output level, obvious signs of distress are encountered, or the prescribed stair step distortion threshold for any harmonic is exceeded. The distortion thresholds get lower at higher harmonics of the fundamental test frequency. For example the 2nd harmonic is allowed to reach -10dB from the fundamental before failing the test but the 3rd harmonic is only allowed to reach -15dB. By the final band if any of the harmonics or noise reach -40dB it causes a fail. The stair stepping down of the allowable percentage of distortion is supposed to correspond with our subjective acuteness to the presence of various harmonic distortions. In general we are much more sensitive to higher harmonics so they are limited much more tightly while the relatively benign 2nd and 3rd harmonics can be allowed to grow rather high before becoming offensive. In theory this works well but it is a complex subject. For instance some systems may be failing for a harmonic that is -35dB down in the final bandwidth while still sounding acceptable to the ear while another may sound obviously distorted with a lot of H2 H3 and H4 distortion yet it passes because of the stair step thresholds. Also two subwoofers may produce a very similar output of say 110dB at 31.5Hz and both may pass but one may sound utterly clean with mostly 2nd harmonic distortion while the other may have higher 3Rd and 5th harmonic distortion but sound a lot more audibly distorted despite having lower total THD. Also many systems may sound ok while failing the distortion thresholds while another sounds very bad and overdriven while passing. This is because when driven to their limits some units exhibit other overload noises or bad sounds that are not harmonically related to the signal input into the subwoofer. These types of sounds are far more audible and offensive than any harmonic related output as these rattles, buzzes, clacks, pops and other artifacts do not blend in with the sound at all and are obviously non-harmonically related to the output at all and typically are a wider bandwidth mechanical sounding noise that is higher in frequency. The CEA-2010 program will sometimes pick these up but not always. Again CEA-2010 provides a good guideline and judging output capabilities but despite being considered clean output according to the distortion thresholds there can be a very large variation in the quality of output from unit to unit despite both receiving passing results. This testing is used to measure distortion and also the maximum useful short term output of a device over various bandwidths. It can give a sense of how much dynamic reserve a system may have. (Note:CEA-2010 documentation actually calls for a measurement from a 1 meter distance and a peak SPL measurement to be reported, however at Data-Bass we follow a reporting method that is a much more typical RMS related SPL and it is referenced at a further distance of 2 meters. There are a number of logical reasons why this method makes much more sense than reporting the peak/1m output. First the peak versus RMS reporting method. These differ by almost exactly 3dB with the peak result being higher of course. However the actual SPL produced by the speaker system does not change. It is just a difference in the way it is reported and calculated from the captured waveform. So why choose one way over the other? An RMS SPL calculation is much more common to see in data and measurements than peak SPL #'s. Much more common. The majority of audio measurement programs default to reporting the rms SPL not peak for the majority of measurements which indicate an SPL and this holds true for loudspeaker development simulation software as well. Again the actual output of the bass system has not changed just the way it is being reported. For example if we put a sine wave sweep into a subwoofer that produces 110dB at 50Hz at 2 meters using a typical rms SPL calculation from the waveform and then without changing the output level at all run the sine wave sweep again with a peak calculation the SPL will appear 3dB louder however the actual bass systems output has not changed at all. The problem is mixing the 2 calculations in one set of measurements. If reporting a peak SPL # for only CEA-2010 versus the rest of the measurements it will have the effect of confusing many people looking at the data. You may look at the maximum long term output measurement and note that the system produced 110dB at 50Hz and then look at the CEA-2010 burst output measurement at 50Hz and see 116dB and think that the subwoofer is capable of bursting 6dB greater output at 50Hz short term but this is not true if the CEA-2010 results are peak results because it adds 3dB because of the different calculation from the peak of the waveform...Actually the subwoofer can produce 3dB greater burst output not 6dB. This is why the CEA-2010 SPL results here are reported in RMS not peak so that they are directly comparable with the rest of the measurements that indicate an SPL presented here, without needing to do a calculation in your head first. A 2 meter distance is chosen for measuring/reporting purposes instead of 1 meter for a number of reasons as well. The CEA-2010 documentation appears to show that the reporting methods were primarily intended or marketed to smaller home audio powered subwoofers, but this type of testing actually was used by Mr. Keele long before the documentation made it a standard and it is not limited in usefulness to only subwoofers, bass systems and or active speakers. It can be used with full range and much larger more powerful devices as well. Here at Data-Bass the subwoofers tested may range from a tiny sealed 8" subwoofer to a behemoth horn loaded monster with multiple 18's intended for arenas...With these larger cabinets and subwoofers having multiple points of radiation a 1 meter distance may still be in the nearfield of large cabinets and the size of the enclosure itself can artificially boost the SPL recorded at such a close distance. Also if the cabinet has drivers or radiation points on differing enclosure faces it is impossible to aim all of the output at the microphone and you may end up with one radiator at a much greater distance from the microphone element than another which can skew the response shape and under represent the output power of the device. Moving the microphone back a further distance to 2 meters helps mitigate some of these effects of large cabinets and allows the output of multiple radiating surfaces to blend together better by minimizing the difference in distance to the microphone element to a larger extent. Also a ground plane measurement is what is known as a half space measurement because there is just the one endless boundary under the microphone and DUT, which provides a near perfect 6dB increase in output over anechoic or full space. Using the inverse square law we know that if the microphone is moved back to 2x the distance from the DUT the output should drop by 6dB. So by reporting results at 2 meters instead of at 1 meter the 6dB drop from the inverse square law cancels out the 6dB gain from measuring in half-space versus full-space and what you end up with is output that is approximate to a 1 meter anechoic or full-space measurement. Yet another reason to measure at 2 meters is to allow headroom in the microphone signal chain. Some of the larger more powerful bass systems tested easily produce outputs in excess of 130dB at 2 meters which would put them in the neighborhood of 140dB at 1 meter which can start to cause issues with clipping in the microphone preamp and soundcard input. In fact a few of the most powerful systems have needed to be measured at 4 meters to ensure that there was sufficient headroom in the measurement chain! Lastly the other 2 large repositories of public CEA-2010 measurements for subwoofers also reported their results in 2 meter ground-plane RMS format likely for the same logical reasons presented here. Despite being a "standard" CEA-2010 results can vary quite a bit and have been hit or miss between the various parties taking them, additionally there are variations in the way they are reported, with the most common being either 2 meter ground-plane rms or the 1 meter ground-plane peak that is specified in the literature. For these reasons it can be difficult to meaningfully compare data from different sources and is often a source of confusion or debate. It is best to just avoid making comparisons to data collected by other sources to those from Data-Bass as it may or may not be reliable and we cannot control the procedures or equipment involved.)

10. A group delay graph is derived from previous measurements. This measurement indicates how much delay or storage of energy versus frequency is taking place in a system. Larger values in MS indicate more latency or energy delay. Ideally there would be zero group delay indicating an incredibly well damped system. In reality there is always some. Generally it is held that as long as the delay is below 1.5 cycles it is inaudible and most who claim to hear differences in delay between speakers would say that anything less than 1 cycle of delay is nothing to worry about. Additionally the deeper in frequency, the longer the wavelength and less sensitive our ears are to it the less audible a long group delay will be. Generally anything below 25-30Hz is not regarded as of much concern unless really bad. For example 40ms of delay at 25Hz is probably not a big deal and not very audible but 40ms of delay at 80Hz is going to be much more audible and of concern. Typically sealed, IB and other lower order systems offer the least amount of delay...Bass reflex systems typically have increased delay near the resonator tuning. Even higher order systems like horns and bandpass enclosures can have more group delay and more complex delay plots. Additionally equalization and other signal processing, such as high pass filters and boost or parametric signal shaping can increase the group delay. Usually this measurement indicates nothing of concern unless the group delay is exceeding 1.5 cycles above 25Hz.

11. Waterfall and Spectrogram plot graphs are derived from previous measurements. These plots are both different ways of representing the amount of energy storage or decay rate in the systems. Resonances, ringing or other issues will show up with a long and slow decay rate. Look for frequencies that seem to hang around longer than the rest and seem to not want to decay away. For Waterfall graphs look for a response that drops off rapidly and cleanly by 25 to 30dB within the first 100ms. Unless there is a very obvious issue with ringing in a particular frequency band there is not usually anything of particular sonic consequence in these graphs. As with the group delay chart most of the energy storage will occur below 30Hz where it is not of much concern. Pay much more attention to issues higher up in frequency as they become much more audible than they are in the depest bass.

12. High power impedance measurements. An impedance measurement will be taken at the power levels corresponding to the voltage inputs used during the long term output sweeps. The results will be used to gauge changes in the impedance magnitude and phase that occur once high power is input into a system and what effects it may have on the load presented to the amplifier. At higher power levels many changes will occur such as changes in impedance magnitude, the sharpness and magnitude of the peaks, the placement of the dips and peaks will shift, the average impedance may rise, etc.This can give clues as to how hot the voice coil and motor of the driver is getting and whether the resonance of the system is shifting, the ports are compressing etc. (Note: This test takes a completely different setup and calibration from the rest and is lengthy and time consuming. It is also every bit as demanding on the DUT as the long term output compression sweeps. That being the case this test is only done occasionally on a particular system in an effort to provide general, rather than system specific knowledge as to what happens to the impedance at high power levels.)



Title: Re: d&b B22
Post by: Ivan Beaver on November 17, 2016, 02:11:35 pm
Ivan, I find great value in the data-bass specs.

I mean, take your specs which have much better disclosure than industry average. The TH-118 shows:  Max Output  137dBSPL/143DBSPL.
Are those max output specs measured, or just calculated from measured sensitivity and extrapolated off OEM driver power-handling?
If measured (hooray!)  Do you use 6dB crest pink? ... for the 6dB diff in specs?
Or do you use sine sweeps as in the sensitivity curves you show?
If using either sine sweeps for max output or simply not measured, what's the basis for the 6dB spread?
And will 137dB hold without compression? And at what distortion level?


We measure using a swept sine wave via TEF.  For subs in particular we measure at a distance of 10M with 28.3V input.  So that comes back to a 2.83V 1M measurement.

The 6dB between continuous and peak is simply the increase in power to a maximum of the driver-with a 6dB peak based on the power capacity of the driver.

This is assuming no power compression-since that takes time.

The 137 will hold for a certain period of time-based on heating.  Of course the actual levels without power compression will depend on the dynamic range of the signal.

We do no measure distortion at full output.  But a horn cabinet will typically be less distortion than a front loaded/ported cabinet simply because the driver is not moving as far.

Title: Re: d&b B22
Post by: Helge A Bentsen on November 17, 2016, 04:28:34 pm
Mircea, that is the exact system i am talking about. We were discussing a lot about it with the EAW engineer that was with us on site. I even had the opportunity to peek inside the OTTO. So i am not at all surprised with the Helge comment :-)

Six of those Ottos ended up in Norway, I've been fortunate enough to play with them and the assosiated Annas, great stuff.

The guys who owns it just did a ballroom tour covering 600 people with one Otto and two Annas a side, that's a lot of people compared to the required truck space.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on November 17, 2016, 05:17:40 pm
I played and listened to stacks with  up to 12 subs a side or more than 40 subs in front of the stage and I can tell you the Otto subs are powerful and clean but not more than a dual 18 like the WS218 X from Martin or a J sub from D&B . I even heard them combined ;)(http://uploads.tapatalk-cdn.com/20161117/069dc15e36bdbb22b755891d6d5aa8fa.jpg)
(http://uploads.tapatalk-cdn.com/20161117/6d4f5fcb7cf66c28d348599a5937a28a.jpg)
Title: Re: d&b B22
Post by: Ivan Beaver on November 18, 2016, 07:07:47 am
Ivan,

The 9dB issue is from comparing a 1m measurement to a 2 meter one. (6dB there)
The other 3dB is the difference from reporting a "peak" SPL from the waveform and an "RMS" SPL. Note that the speaker output or waveform has not changed. Only the method of reporting the output. This is explained in the CEA-2010 section below. Also note that a lot of places or manufacturers are reporting a 1m half-space "peak" output. That's not what I do at Data-Bass I use a much more conservative and IMO more realistic 2 meter half-space (1m full-space) SPL reported from the "rms" method of analysis of the waveform.


Yes, the standard is a 1M SPEC-but not measurement distance.  Back calculations are often used.

HOWEVER, in many cases (especially with subs) actually measuring at 1 or 2M will NOT give a number that is useful in designing sound systems.

When designing we need to know how loud it will be at certain distances (NOT at 1 or 2 M)

So Danley (and others) measure at a further distance-and then "back calculate" to get the 1M equivalent.

Danley uses a 10M distance and 28.3V.  So a 20 addition in voltage offsets the 20 dB loss in distance.

If you measure at 1M you will not get our spec numbers in many cases (on our tops or subs)

But if you use the 1M number and figure out the level at say 40M, you will get a number that will be right at 40M-or any other distance that is further away than a couple of meters.

In some cases, the actual measurement at 1M is 6dB or lower than the spec.  But at a distance-the numbers are correct.

This all has to do with the size of the device, the acoustic origin of the sound and the measurement distance.

You need to get far enough away so that the numbers will be repeatable at different distances.

To me, the numbers in a spec sheet need to be useful to a designer for figuring out if a particular loudspeaker will cover the intended area-at the needed SPL and have a freq response that is proper for the intended application.

Having specs that include "3dB for the crest factor of a sine wave" are misleading-at least in my opinion.

That is not something that can be measured with normal test gear on site and will not be realized in any way by the end user.  Yet can lead to designing a system that not quite loud enough for the intended application.

To me- it falls into the "Peak SPL" that is based on a single freq that sticks out in the freq response.  People "think" the speaker can produce that over the whole bandwidth, but in reality it is only a very narrow freq that must be notched out in order to sound good.

In some cases, this results in a number that 10dB greater than what you can actually achieve out of the cabinet.  But some people like to believe this "simple number" and will argue that XYZ speaker is louder than ABC speaker because it had a 10dB greater peak SPL.  Truly sad in my opinion.

But that is just my opinion.  I know others feel different.
Title: Re: d&b B22
Post by: Marjan Milosevic on November 18, 2016, 10:50:28 am
I feel exactly the same.
It is really sad looking at the spec by most of the top dogs and realizing they are extremely misleading.
It then force others to jump in the same wagon or they will have very hard time presenting a comparable product because on paper it will look inferior.
People love looking at big numbers. And that fact is used by marketing departments.
Title: Re: d&b B22
Post by: Josh Ricci on November 18, 2016, 03:04:16 pm
Hello Ivan and Marjan,

I fully agree with both of your last posts. The creative use of numbers & specs is alive and well. It's hard to blame the manufacturers either. Consumers love big numbers. The bigger the better. More SPL YEAH! More watts! If you start losing sales to other companies who are rating their products in a completely different manner that isn't comparable in the least, but less educated buyers do not know any better, that's not a good position to be in. You could attempt to start an education initiative to trickle down knowledge to the wider market base and trust that the products eventually gain a following based on use in the field (Difficult and long term) or you can simply change some spec sheets, potentially gain some sales immediately and go on with the rest of your probably busy schedule (cheaper and quicker). It's not hard to see how this happens.

BTW Ivan,

Sorry about the huge book of a post but someone had brought up Data-Bass so it was easier to copy/paste than retyping all of that.

My measurements are usually taken at 1,2,4 and 10m for each system so it is known how the proximity to the cab under test is affecting the response. In general the large cabinets lose a bit of apparent bass response at 10m. Not a huge amount but a couple of dB isn't uncommon for a larger cab. Also the response tends to smooth out a little at distance. The only time that I have seen that the 10m 10x voltage measurement is higher than the 1m measurement is when the cabinet radiates from multiple surfaces. The 10m sensitivity measurement is made with 10X voltage versus the 1m, etc. I cannot measure much further than 10m because background noise becomes a serious issue as does the proximity of large buildings a couple hundred feet back on the very lowest frequencies tested. It would be a rare place indeed that has the space and noise floor needed for bass measurements at even greater than 10m distances.

The SPL numbers are reported as what is functionally 1m full space (2m half space equivalency.) They are not measured at 1m other than the 1m sensitivity measurement in most cases. The big, powerful cabs end up needing measured at 4 meters in most cases to ensure headroom in the mic/preamp anyway. A few have been at even greater distances. It all gets normalized back to the 1m full space SPL for exactly the reasons you pointed out in your post. For comparison and ease of calculations sake. Also the largest systems I have measured to date are single cabs with not much more than 2000sq in of frontal area. Big but not out of the ordinary for large subwoofers and small relatively compared to a block of multiple subs. A 24x48 frontal area such as a common 2x18" BR is  1152sq in. There is a trend seen as the microphone distance is increased, when comparing the measurements of single cabs in that size range , but generally there is little difference seen comparing a 4m or in some cases a 2m measurement and a 10m one. Most of the "boost" seen at 1m is gone once beyond 2 or 3m distance outdoors. This is with moderate sized, single cabs though. A block of 8 cabs would be a different story and need greater measurement distances. 
Title: Re: d&b B22
Post by: Ivan Beaver on November 18, 2016, 07:20:08 pm

My measurements are usually taken at 1,2,4 and 10m for each system so it is known how the proximity to the cab under test is affecting the response. In general the large cabinets lose a bit of apparent bass response at 10m. Not a huge amount but a couple of dB isn't uncommon for a larger cab. Also the response tends to smooth out a little at distance.
I would argue that it is NOT that they lose output at 10M, but RATHER that the measurements made up close include false bass INCREASES. 

This is particularly present in large cabinets.

That is EXACTLY why we don't measure up close.  It gives a false sense of what the cabinet can produce at far distances.

So while the numbers would actually be what is measured- it CANNOT be translated into what would be expected at further distances.

So it comes down to whether you are selling "numbers" or something that will actually perform as the specs say.

People have different opinions on this-depending on whether you are selling or buying------
Title: Re: d&b B22
Post by: Art Welter on November 22, 2016, 09:57:18 pm
1)measurements made up close include false bass INCREASES. 
This is particularly present in large cabinets.
2)We measure using a swept sine wave via TEF.  For subs in particular we measure at a distance of 10M with 28.3V input.  So that comes back to a 2.83V 1M measurement.
3)The 6dB between continuous and peak is simply the increase in power to a maximum of the driver-with a 6dB peak based on the power capacity of the driver.
This is assuming no power compression-since that takes time.
The 137 will hold for a certain period of time-based on heating.  Of course the actual levels without power compression will depend on the dynamic range of the signal.
4)We do no measure distortion at full output.  But a horn cabinet will typically be less distortion than a front loaded/ported cabinet simply because the driver is not moving as far.
Dear Ivan,

1) Your statement is inconsistent with your measurement guru's dictum.
I'll cite it if you ask politely, but don't want to embarrass you with it, we all have our "drunk posts" that we have to walk down the "hall of shame" while holding the trophy with some appendage of our shamed existence held prominently for all to see.
Having far too many "shame walk" atrophies evident in my copious "drunk post" historical evidence, which progressively disappear from the inter-webs at the approximate rate of  their initial propagation, I regret any "collateral damage" inflicted in my reply to your dissertation.
2) The "power capacity" of the drivers DSL uses are simply reprints of the AES rating of the driver taken in free air.
When the driver is loaded in a "tapped horn", the impedance of the driver is far lower than in free air.
Since the AES rating is based on the nominal impedance, not your DSL TH impedance, your power specification is inflated by a rather large factor.
As an example, let's use the DSL TH-118 loaded with a "4 ohm" B&C 18SW115 rated for 1700 Watts.
To drive a nominal 4 ohm load to 1700 W requires 82.5 volts, so we assume that is the voltage used for the AES test, even though the driver's average free air impedance is far higher- the driver is actually dissipating a fraction of the "watts" specified.
Put the same "4 ohm" B&C 18SW115-4 in your DSL TH-118 and apply the same "continuous" 82.5 volts at Fb, where impedance is as low as the 3.3 Re DCR of the driver and in about twice the time it takes Porky Pig to say " ba ba be  hey hey hey, presto",  the smell of burnt adhesive will start to be evident near the cone.
Leave that sine wave tone fixed at Fb another 30 seconds or so and the smell will be enough to drive you out of the room unless you have an air evacuation fan going full tilt for a cold December half hour (true story). Wish I had more than a 1500 Watt heater in the shop..
Now take that "warmed up" driver, and apply halfway between the "continuous" 1700 Watts (those Watts that used to be redundantly called Watts RMS) and the peak rating of 6800 Watts, "3400 Watts" requiring 106 volts.
I don't presently own an amp that can put out  3400 Watts continuously, but I guarantee the "poor little" 115mm double sided double wound 18SW115 voice coil won't last long even if you use 106 volts (RMS, not peak) pink noise rather than a sine wave at Fb.
Yes, cooling is better when the cone is violently flopping around, but we can't determine the musical proclivities of end users, EDM "drones" may have less crest factor than the "terrible" 3dB of a sine wave.

In weeks of abusive testing, and years of shows ranging from jazz to hip hop to EDM, I never had any problem with the B&C 18SW115-4 loaded in my Welter Systems Keystone Sub design, also "sporting" the same 3.3 ohm impedance minima at Fb the DSL TH-118 has.
The fellow I sold the original pair of Keystone Subs to managed to burn one up in the first week.
My guess is he accidentally panned kick and/or bass hard left, leaving one sub to do +6 dB more "heavy lifting" to achieve the level he became used to on the first several gigs.
Bass is addictive, I see +5, +10, and +20 addicts ruining our collective lives on an ever more frequent "bass"is.
A single mono bridged Crest CA 9 driving one Keystone sub can't put out more than 80 volts while drawing 37.8 amperes from a 120 volt line.
37.8 amperes line voltage to a shade under 100 volts, when directly connected to a mains power transformer with about 40 feet of 4AWG to the mains panel, and 100 feet of 10AWG to the amplifier.
If the Crest CA 9 were run anywhere near that 80 volt output level the 20 amp circuit breaker the fellow's amp rack with two other amps of equal power draw on the same circuit would have popped, but the breaker didn't, the coil lost it's immortal soul.

The "take away" from all this is your specifications are not "real world", so you constantly have to inform your DSL clients to limit the speaker to some small  fraction of the AES rating your DSL specs are based on, or they will let out the "magic smoke" and stink up the area surrounding the DSL cabinet.

This is the choice made when DSL wrote specifications based on fictional "power" ratings, like so many companies play the grid iron playing field here.
Yet you have  always liked to play from the top of the hill, showering us with  "trickle down" theories like a "golden shower" of truth on the 49% of the 99% inhabiting the USA;^).

2) I like to firmly bolt my drivers down, how far is "too far" for a driver to move?
Thanks for finally updating your TH-118 specs to the 18SW115 AES ratings rather than the 18NLW9600-4 that is still pictured and your tips six years ago about why the B&C is the better choice :^).
Sometimes I wonder if M.H's influence has shifted you, but I know the "force" is strong deep within you, Ivan- do not succumb to the "Dark Side".

Jokes aside, the reason the 15.2 gross cubic foot Keystone Sub "tapped horn" also loaded with the B&C 18SW115-4 delivers 6 dB more average SPL in the 40-100 Hz pass-band than the same driver in a 9.24 gross cubic foot "bass reflex" enclosure with the same low corner frequency is because the driver is forced into "doing more work" for a given excursion.
Work is hard, some "force" always will pay for any work done in the omni-spherical dimension we inhabit.
Yes, the Keystone Sub "horn cabinet" delivers more SPL for a given input voltage, but the TH will also have more distortion at that voltage than a BR.
Recently, while reviewing TH distortion and SPL compared to BR, while also comparing impedance curves, found the Keystone had "compression" at the upper end of the pass band at "only" 77.5 volts of sine wave input, while the BR was the opposite, due to "port compression".
The impedance curves made obvious "what went on".
Impedance is kind of like a variable frequency chastity belt, the upper reduction in the TH SPL was due to it's upper pass band low impedance dips "sucking, or demanding" power, while the BR has a steadily rising impedance "spurning, or rejecting" the Scottish Watt's "power".
The more power the voice coil "sucks" surrounding the pole piece, the hotter it becomes, which makes it's impedance rise, protecting it from the very "power" that heated it up, a cosmic entropic conversion of energy, - sex, drugs and rock and roll are not required to witness the conversion, but two of three are usually involved.
Since most of us audioholics test from "bottom" up, my sine wave tests were also started at the bottom of the pass band, that way you can only go "up".
The average increased excursion down low provides ample "heat pumping" (forced cooling), then proceeds to upper frequencies, which progressively pump less heat from the voice coil.
Ouch, too hot to touch- and that smell..
The upper pass band compression noted in the TH compared to the BR was due to the lower upper impedance causing voice coil heating, raising impedance, causing power compression- at 77.5 volts, after considerably less than 50% duty cycle over a few minutes time.
I know the duty cycle was less than 50% because I am "digitally challenged" and it took me more time to save each record than it did to let the SMAART screen settle down.

 Data in post # 12 here:

http://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers.html

"Full power" should have been 82.5 volts, not 77.5 volts.
77.5 volts is 1500 Watts into a nominal 4 ohm load, the B&C 18SW115-4 is rated for 1700 Watts AES. I accidentally substituted another B&C driver's AES rating, and conducted the test at a fraction of a dB "too little" power.
As the Immortal Carroll Shelby said: "Too much power is Just Enough".
I bet Carroll burned up a lot more 427 Cobra engines than I have drivers, but his drivers got paid more than mine ;^)..

Cheers,

Art
Welter Systems, Inc.
Title: Re: d&b B22
Post by: Ivan Beaver on November 23, 2016, 10:19:26 am
Art, I understand what you are saying, but I wanted to add some comments for those "playing along at home".

The power handling tests are NOT flat (they rolloff on the high AND low freq), and they are for specific time periods.

They are also not sine waves at specific freq.

So as you go lower, there is less energy applied to the woofer.

Personally, I feel that these test curves do not represent modern music.  They are from years ago when we did not have as much bass present in music.

So if a flat response curve is used, the power capacity would go down.  And marketing depts would simply not allow that.  So we are stuck using the same test signals.

Yes, at certain freq, the impedance does get a little bit low, but at other freq it is quite a bit higher than the 4 ohm spec.

Yes we use the standard impedance numbers.  BELIEVE ME, if you put down anything other than 2-4-8-16 ohms the phones will start to ring off of the hook with people who cannot figure out what amp to use with a 6 ohm speaker.  YES it did happen back when the Sh50 was rated for 6 ohms.  We changed the "paper number" to 4 ohms and the phones stopped ringing with that question and sales went up-because it was a rating people could understand. :(

The reason I (and many others) often tell people to run long term limiters at 1/4 to 1/3rd continuous power has nothing to do with the rating of the driver or how it is rated.

And EVERYTHING to do with the typical usage for EDM or dance shows.  Very often pure sine waves are used.  And NO MANUFACTURER (that I am aware of) rates their speakers using sine waves anymore.  Years ago-yes, but not now.

Agreed sine wave will heat up a speaker VERY quickly-IF the freq is in a impedance low spot.

Also these shows are not your typical "rock show".  They go on for many hours and sometimes DAYS, with NO break in the sound.  So the driver just keep getting hotter and hotter. 

The specs are not for 24 hour operation.

This applies to ANY loudspeaker model.

So-as usual-there are a lot of things to consider when looking at the "simple number specs".
Title: Re: d&b B22
Post by: Nathan Riddle on November 23, 2016, 10:50:46 am
When I get rich I want to buy and test every speaker/sub/amp/dsp/mixer/light and use what y'all say/wish and remove the "I have/cant do this 'cuz marketingz" and just put everyone/everything on the same ballpark and test and test and test and then random people on the interwebs can have their cake/pie and eat it too.

In the meantime, I enjoy the conversations and eat my popcorn  ;)
Title: Re: d&b B22
Post by: Ivan Beaver on November 23, 2016, 01:29:11 pm
When I get rich I want to buy and test every speaker/sub/amp/dsp/mixer/light and use what y'all say/wish and remove the "I have/cant do this 'cuz marketingz" and just put everyone/everything on the same ballpark and test and test and test and then random people on the interwebs can have their cake/pie and eat it too.

In the meantime, I enjoy the conversations and eat my popcorn  ;)
Back before the turn of the century, I thought that if I won the lottery, I would start a REAL review magazine.

I would buy the products and then test and use them as I saw fit.

Then publish the results.  I would not accept any advertising, so would be free to publish what I wanted.

People would read it to get an unbiased opinion.

Of course, I need to win the lottery FIRST--------------
Title: Re: d&b B22
Post by: Tim McCulloch on November 28, 2016, 07:40:46 pm
Back before the turn of the century, I thought that if I won the lottery, I would start a REAL review magazine.

I would buy the products and then test and use them as I saw fit.

Then publish the results.  I would not accept any advertising, so would be free to publish what I wanted.

People would read it to get an unbiased opinion.

Of course, I need to win the lottery FIRST--------------

Consumer Reports does basically all that, albeit under more controlled or monitored use than "as I saw fit."

Production Partner (oh, how I wish I'd learned German) doesn't purchase the products it reviews but they are very thorough in their reviews and analysis.
Title: Re: d&b B22
Post by: Ivan Beaver on November 28, 2016, 08:20:21 pm


Production Partner (oh, how I wish I'd learned German) doesn't purchase the products it reviews but they are very thorough in their reviews and analysis.
Agreed.  There is also a Polish pro audio magazine that does the same sort of thing.

They are LIGHT YEARS ahead of what we "Americans" have for "reviews" of gear.
Title: Re: d&b B22
Post by: Al Rettich on January 26, 2017, 09:01:29 pm
Personal preference. I've heard Otto subs sound good, and I've heard them sound bad. This can be said with most line array cabinets. It has A LOT to do with the person designing and implementing it. I've had great shows on VerTec in one city, go to the next town same 4889 rig, and it sounds 180 degrees different.. Difference, was person designing and implementing it.
Otto walks all over the B2/22/J-infra but it has a hefty price tag.


Sent from my iPhone using Tapatalk
Title: Re: d&b B22
Post by: Ryan Hargis on March 13, 2017, 02:51:24 pm
I've had great shows on VerTec in one city, go to the next town same 4889 rig, and it sounds 180 degrees different..

It must have been out of polarity  ;)
Title: Re: d&b B22
Post by: Tim McCulloch on March 13, 2017, 04:43:53 pm
Personal preference. I've heard Otto subs sound good, and I've heard them sound bad. This can be said with most line array cabinets. It has A LOT to do with the person designing and implementing it. I've had great shows on VerTec in one city, go to the next town same 4889 rig, and it sounds 180 degrees different.. Difference, was person designing and implementing it.

Mix on one of our VerTec rigs, Al.  You'll like it... or else. ;)
Title: Re: d&b B22
Post by: Erik Jerde on March 13, 2017, 06:26:52 pm
All d&b loudspeakers are absolutely REQUIRED to be used exclusively (in the most literal sense of the word) with d&b amplifiers.

Quite simply, you do not ever use d&b loudspeakers without d&b amplifiers.

Funny thing, I freelance with the live department of a local company who is a d&b dealer.  One of their guys was telling me about going out to do some work on an old(er) install which he hadn't seen before.  Turns out the client had someone else in and got sold a bunch of crown amps to replace the d&b amps.  I don't know if thy still had the original amps.  Suffice to say the rig didn't sound right.
Title: Re: d&b B22
Post by: Don T. Williams on March 13, 2017, 07:26:46 pm
Ouch!
Title: Re: d&b B22
Post by: Helge A Bentsen on March 14, 2017, 08:10:51 am
Powersoft got presets for several d&b boxes these days.
Rumor has it they work rather well.
Title: Re: d&b B22
Post by: radulescu_paul_mircea on March 14, 2017, 01:39:00 pm
Exactly! If one knows what he's doing, I don't see why not use them with other amps. Especially if it's an readily available amp model
Title: Re: d&b B22
Post by: Don T. Williams on March 18, 2017, 03:22:39 pm
Exactly! If one knows what he's doing, I don't see why not use them with other amps. Especially if it's an readily available amp model

While that may be true, d & b will not let anyone purchase their cabs without the d & b amps.  That has become true of many of the big system manufactures (JBL with Crown, etc), and I understand the advantages for cross renting and consistency. 

I'm hoping that doesn't start extending to other parts of a system.  There is nothing wrong with Yamaha consoles, but I would hate to have to buy one to get a Nexo rig, as an example (insert JBL/Soundcraft, Martin/Mackie, and others).
Title: Re: d&b B22
Post by: Ivan Beaver on March 18, 2017, 03:40:10 pm
While that may be true, d & b will not let anyone purchase their cabs without the d & b amps.  That has become true of many of the big system manufactures (JBL with Crown, etc), and I understand the advantages for cross renting and consistency. 


I have not heard that you can't buy JBL speakers unless you buy Crown amps.

When did this happen?
Title: Re: d&b B22
Post by: David Sturzenbecher on March 18, 2017, 06:50:05 pm
I have not heard that you can't buy JBL speakers unless you buy Crown amps.

When did this happen?
This currently only applies to the VTX line of speakers.   


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Title: Re: d&b B22
Post by: Tim McCulloch on March 18, 2017, 07:33:40 pm
I have not heard that you can't buy JBL speakers unless you buy Crown amps.

When did this happen?

If you want V5 processing and presets you buy ITech HD or powered boxes.
Title: Re: d&b B22
Post by: David Sturzenbecher on March 18, 2017, 07:35:53 pm
If you want V5 processing and presets you buy ITech HD or powered boxes.
If you want official V5, then yes. If you are happy with an amp that has the same transfer function as V5, there are options.


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