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Title: Which subs to buy? Paralysis by analysis
Post by: Mark Monson on October 05, 2014, 01:25:08 am
My classic rock band has been in the market for subs for the past 6 months, but every time we think we know what we want we find out about another sub that may work better for us.  We have Peavey QW4 for mains.  One of the main problems is that we can't find anywhere to listen to most of the subs, let alone A/B them.  We have looked at Peavey QW218, then VR 218, JBL SRX 728, STX 828, EV Qrx 218, Yorkville LS 1208, LS 2104 (which seems to be a real good sub on paper, but we can't find much information about it) Danley TH 118 and JTR Orbit Shifter.  My impression from reading comments on the internet is that the Danley may be a cut above the rest.  The sensitivity is listed at 108db 1w 1m.  Does this mean that it would take only 25% of the power to produce the same spl as a sub with 102db sensitivity? (or am I not understanding the 3db=2x the power rule).  Saving on power amps would certainly be a plus.  Right now we are leaning towards new VR 218 or used TH118.  We would appreciate some help from any of you who have heard these subs.

thank you
Title: Re: Which subs to buy? Paralysis by analysis
Post by: David Sturzenbecher on October 05, 2014, 07:30:09 am
Danley doesn't rate their subs with 1W 1M. They use 2.83V.  Which for an 8 ohm cabinet is essentially 1W/1M.  But for a 4ohm cabinet it's more like 2W/1M.  So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.


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Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 10:10:49 am
Danley doesn't rate their subs with 1W 1M. They use 2.83V.  Which for an 8 ohm cabinet is essentially 1W/1M.  But for a 4ohm cabinet it's more like 2W/1M.  So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.


Sent from my iPhone using Tapatalk
The reason we use 2.83 volt for everything-is very simple.  People who say they are "applying 1 watt" are lying.

They are apply A VOLTAGE- and the resultant wattage depends on the impedance.

HOWEVER the impedance is not what the specs say-it may be at some freq-but could be higher or lower at other freq.

So for an 8 ohm speaker (at the freq that the actual impedance IS 8 ohms)-2.83V is 1 watt.  At other freq for that same freq the power could be more, but in many cases is less.  It just depends.

The spec numbers choosen by manufacturers come down to the nearest "standard" value-2-4-8-26 ohms.

People get REAL confused if you say a speaker has an average impedance of 6 ohms.  Even though that statement may be correct-they simply cannot figure out what amp to use-since they don't see ratings for 6 ohms.

Call that same speaker 4 ohms and everybody is happy.

Take our Th115 4 ohm for example.  It is not 4 ohms, but closer to 5 ohms-if you look at the IMPEDANCE CURVE.  But 4 is the closest standard value so that is the rating.

This is yet another example of trying to use a "simple answer" to a complex question.

Agreed the best thing is to LISTEN-because there are many things that show up sonically that do not show up on a spec sheet.

And listen at both low and loud levels.  What happens at a lower level does not always translate to what happens at higher levels.

And when looking at max SPL-yes those are calculated numbers that the speaker can produce.  But that DOES NOT mean you actually want to listen to the speaker at that level.  Some sound fine at higher levels and other not so fine.  But you don't find that on the spec sheet-ONLY by listening.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 11:05:09 am
Something else you HAVE to consider.

Where does the sensitivity number ACTUALLY come from?  It would be nice if all subs had a flat response-but they don't.

Is it some peak in the response-or an average within the intended operating range of the loudspeaker?  Those can be QUITE different.  And the peak number is not lying-but it certainly is not "telling the truth".

Without a measured freq response curve-it could be at freq COMPLETELY out of the operating band of the sub.

A very famous manufacturer used to have rating for their subs that were "20-20Khz".

That's what we want-right?  full freq measurement?"

NO

In one case a 2x 18" had a VERY high sensitivity rating-but it was for a peak at 1800Hz.

COMPLETELY out of the range of intended usage.  They did not lie-they just did not "answer the  question" the way people want it answered.

With subs-most can get pretty loud above 100hz.  So if the "specs" were taken at say 150Hz, then how well can you translate into how loud it will be below 80Hz.

You can't, without a measured response curve..

THAT is why it is SO important to see the response curve-and see how loud it is at particular freq-NOT just take the "simple data" from the spec sheet.

I have seen quite a number of subs that state low freq points of say -3dB, but when you look at THEIR OWN measured data, the actual level is more like 9dB down.  I have actually seen some products that are 20dB down at the "stated -3dB" point.

You HAVE to look closer to get the real answer.

Of course listening will often separate the products quickly with things that don't show up on spec sheets.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mac Kerr on October 05, 2014, 11:05:45 am
The reason we use 2.83 volt for everything-is very simple.  People who say they are "applying 1 watt" are lying.

They are apply A VOLTAGE- and the resultant wattage depends on the impedance.

HOWEVER the impedance is not what the specs say-it may be at some freq-but could be higher or lower at other freq.

So for an 8 ohm speaker (at the freq that the actual impedance IS 8 ohms)-2.83V is 1 watt.  At other freq for that same freq the power could be more, but in many cases is less.  It just depends.

The spec numbers choosen by manufacturers come down to the nearest "standard" value-2-4-8-26 ohms.

And by using those "standard values" their 4Ω speakers don't automatically seem 3dB louder because they are just as arbitrarily seeing 2.83V as opposed to the voltage that corresponds to 1W into 4Ω. Using a different standard of applied signal just means specs can't be directly compared between speakers, neither one is more correct or more accurate than the other, it is just a matter of symantics.

Yes, the language of 1W/1m is not as specific as 2.83V, but the value of 2.83V is either completely arbitrary, or it's based on the same assumption of 8Ω as a "standard" impedance.

Mac
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Scott Bolt on October 05, 2014, 01:03:13 pm
Ivan,

Nice comprehensive explanation!

The only thing I would add to your very comprehensive explanation is that there is no specification in existence that can tell you if the speaker sounds good.

The best way is to hear them ;)
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mark McFarlane on October 05, 2014, 01:29:52 pm
...

I have seen quite a number of subs that state low freq points of say -3dB, but when you look at THEIR OWN measured data, the actual level is more like 9dB down....


Perhaps because they call the peak +6db? Or it's -3db from the average across some unknown freq range.  The fun of spec sheets.

Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 02:16:05 pm
And by using those "standard values" their 4Ω speakers don't automatically seem 3dB louder because they are just as arbitrarily seeing 2.83V as opposed to the voltage that corresponds to 1W into 4Ω. Using a different standard of applied signal just means specs can't be directly compared between speakers, neither one is more correct or more accurate than the other, it is just a matter of symantics.

Yes, the language of 1W/1m is not as specific as 2.83V, but the value of 2.83V is either completely arbitrary, or it's based on the same assumption of 8Ω as a "standard" impedance.

Mac
Except you can easily apply 2.83v and measure it and be consistent

You cannot apply 1 watt at least not consistently due to the varying impedance
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 02:25:40 pm
And by using those "standard values" their 4Ω speakers don't automatically seem 3dB louder because they are just as arbitrarily seeing 2.83V as opposed to the voltage that corresponds to 1W into 4Ω. Using a different standard of applied signal just means specs can't be directly compared between speakers, neither one is more correct or more accurate than the other, it is just a matter of symantics.

Yes, the language of 1W/1m is not as specific as 2.83V, but the value of 2.83V is either completely arbitrary, or it's based on the same assumption of 8Ω as a "standard" impedance.

Mac
I would also that many if not all 4 ohm subs are dissipating well under 1 watt at some freq

So using the 1 watt designation is as bad as using a sensitivity number that is high because it is outside of the operating band

Once you start talking average within the operating band everything starts to change-the powe the sensitivity, the impedance etc

At least with 2.83volts that does not change with freq so it is constant and continuous regardless of freq

That is the reason we use it. Even if it is different than the falsehood that some people think they understand-but are wrong
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Keith Broughton on October 05, 2014, 04:39:31 pm
My classic rock band has been in the market for subs for the past 6 months, but every time we think we know what we want we find out about another sub that may work better for us.  We have Peavey QW4 for mains.  One of the main problems is that we can't find anywhere to listen to most of the subs, let alone A/B them.  We have looked at Peavey QW218, then VR 218, JBL SRX 728, STX 828, EV Qrx 218, Yorkville LS 1208, LS 2104 (which seems to be a real good sub on paper, but we can't find much information about it) Danley TH 118 and JTR Orbit Shifter.  My impression from reading comments on the internet is that the Danley may be a cut above the rest.  The sensitivity is listed at 108db 1w 1m.  Does this mean that it would take only 25% of the power to produce the same spl as a sub with 102db sensitivity? (or am I not understanding the 3db=2x the power rule).  Saving on power amps would certainly be a plus.  Right now we are leaning towards new VR 218 or used TH118.  We would appreciate some help from any of you who have heard these subs.

thank you
Grab some TH118s. you won't be dissapointed.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 04:41:13 pm

Perhaps because they call the peak +6db? Or it's -3db from the average across some unknown freq range.  The fun of spec sheets.
If the low freq number is not directly tied to the sensitivity number-then they don't mean anything-or they could mean "anything".

For example:  If you want higher sensitivity number to put on the spec sheet-then that means that the low freq number ALSO will be higher.

Or if you want a lower freq number-then the sensitivity number will be lower.

You DO NOT (or shouldn't anyway) get to choose the numbers independently.

ONCE AGAIN you see the IMPORTANCE of showing the actual MEASUREMENT-so the user can "choose their own numbers" from the graph or interpret how they want to read it.

For example: If you have a measured response you can look at it and see what the sensitivity is at a particular freq and then "do the math" and figure out how loud it can get at that freq.

Without a measured response-you have NO IDEA how loud it is at a particular freq. and no way to even begin to guess-unless you measure it yourself.

I know I harp on this a lot- BUT IT IS IMPORTANT-at least as a first step to figuring out the actual performance of a particular loudspeaker.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ara Ayrassian on October 05, 2014, 05:06:13 pm
Danley doesn't rate their subs with 1W 1M. They use 2.83V.  Which for an 8 ohm cabinet is essentially 1W/1M.  But for a 4ohm cabinet it's more like 2W/1M.  So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.


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Prior to having Danleys I had a pair of JBL 4719A subs I purchased a pair of TH115's 4 ohm and when I did a A & B test there was absolutely no comparison the Danleys were a overall winner.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 05:37:48 pm
Danley doesn't rate their subs with 1W 1M. They use 2.83V.  Which for an 8 ohm cabinet is essentially 1W/1M.  But for a 4ohm cabinet it's more like 2W/1M.  So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.


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If you want to "play a little game", take a look at the Th118 spec sheet.

http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/04/TH-118-spec-sheet2.pdf

Look at 93ish Hz.  see that impedance peak?  Now look at the amplitude at that freq.

The sensitivity is around 109dB with the 2.83V input.  Which is less than 1 watt at that freq.  So figuring the impedance is around 9.2 ohms-the voltage required to get 1 watt is a little over 3 volts.  The difference between that voltage and 2.83V (the applied voltage) is around 0.6dB.

So using the "1 watt" method-the cabinet produces around 109.6dB with 1 watt (at one freq) below 100hz.

So the cabinet "could" be rated at 109.6dB below 100Z 1W/1M and still not be lying.

AND WHILE WE ARE AT IT-what does the 1M really mean?

Danley does not measure the subs at 1M.  If we did, then the ACTUAL MEASUREMENT would be HIGHER.

We measure subs at 10M (a 20dB loss in distance) and drive at 28.3V (a 20dB increase in level) so they cancel each other out.

So this brings us to the REAL reason for specs.  What is that?

In my opinion, it should be used so that an sound designer can get an idea of what a particular product will perform like at some distance (NOT 1M) away from the cabinet.

If Danley were to use the actual SPL measured at 1M, then at say 20M away the SPL somebody would measure would be LESS than the calculated SPL-using the 1M spec.

But by using the 10M measurement-and "back calculating" you end up with a number (all be it lower than what it actually measures at 1M) that WILL calculate out to longer distances-so the number presented is actually USABLE and not some "inflated number" that looks good on a spec sheet.

Now this works the opposite way as well.

Take the Danley SH25.  If you were to actually measure it at 1M, you would read LESS than the rated sensitivity by almost 6dB.

So is this number false?  NO.  The number is used to figure out how loud the cabinet will be at a longer distance-and it is measured a distance away and again, back calculated to 1M

So why is the measured number lower?  It is because of the depth of the horn.

In the SH25 the acoustic origin is physically almost 1M behind the grill.  So it has undergone a good bit of "expansion" before it even gets to the grill-so the mic is actually close to 2M away from the acoustic origin or source.

But if you use the rated sensitivity and figure out the SPL at say 20M-the number you would measure is the same as the calculated.

Once again-it is IMPORTANT to understand what the numbers actually mean and where they come from-how they are determined etc.

The numbers should translate into the REAL WORLD in a way that is useful to a designer.

If not-then they are pretty much useless.

PS  I know that some other manufacturers use the same methods-but not all.  Hence the reason to know where the numbers come from.

Are they on the spec sheet to look good-or to actually MEAN something useful?

That is often a tough question.  Who put them there-the engineering team or the marketing team?
Title: Which subs to buy? Paralysis by analysis
Post by: David Sturzenbecher on October 05, 2014, 07:23:26 pm
If you want to "play a little game", take a look at the Th118 spec sheet.




No thanks, I'm good. Nothing you haven't preached on numerous times before.  Most of my use for spec sheets anymore is to find out how much something weighs, so I can tell someone else how heavy it is so they can lift it for me... And to maybe get an idea of how to power something. But typically I already know that from the last job. There are much better methods for finding out all the other stuff. You can't tell how good a speaker sounds from a spec sheet. I have heard speakers with really good specs sound really bad.




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Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 05, 2014, 07:40:53 pm
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Not to mention it is difficult to look at spec sheets when they don't download properly. I wish website designers wouldn't require special "somethings" in order to use their sites.....
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Bob Leonard on October 05, 2014, 07:45:42 pm
Really Ivan, WTF, does every reply have to be a sermon?

OP,
Any of the subs you listed will do a decent job for you. I would look towards the SRX728 which are obsolete, but can be found, and will do a very good job. The only thing you may not like about the 728 is the size and weight, but it is a formidable dual 18" cabinet that many of us rely on with great success and very, very few failures. The STX 828 is also a great sub with the same capabilities as the 728. The drivers are not the same, and the 2242 used in the 828 will produce good quality sound at slightly lower frequencies than the 728, but either sub will produce very high quality sound capable of rolling your socks up and down at high levels.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 05, 2014, 07:53:52 pm
Really Ivan, WTF, does every reply have to be a sermon?

OP,
Any of the subs you listed will do a decent job for you. I would look towards the SRX728 which are obsolete, but can be found, and will do a very good job. The only thing you may not like about the 728 is the size and weight, but it is a formidable dual 18" cabinet that many of us rely on with great success and very, very few failures. The STX 828 is also a great sub with the same capabilities as the 728. The drivers are not the same, and the 2242 used in the 828 will produce good quality sound at slightly lower frequencies than the 728, but either sub will produce very high quality sound capable of rolling your socks up and down at high levels.

Sales? lol.

Is a dual 18" OK for the OP? The 728s are 168lbs... just wanted to make sure. A pair of the 718S will make it easier to deal with, if the weight ended up being a concern...
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Peter Morris on October 05, 2014, 08:48:45 pm
Danley doesn't rate their subs with 1W 1M. They use 2.83V.  Which for an 8 ohm cabinet is essentially 1W/1M.  But for a 4ohm cabinet it's more like 2W/1M.  So a TH-118 would have to be derated by 3dB to compare "spec for spec" to other 4 ohm subs.... Which isn't the best practice anyway. Your best bet is to do exactly what you did, and listen for yourself.


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Agree, and FWIW I don’t think its good practice either, just about every other manufacture specifies 1 watt per meter referenced to the nominal impedance. E.g. - 2.83 volts for 8 ohms and 2.0 volts for 4 ohms.

We measure how powerful speakers (and amplifiers) are in watts, and it’s logical to compare their efficiency relative to watts.
 
I understand impedance, and all the issues Ivan discusses.  I just think what Danley is doing can be misleading, especially for those people who don’t fully understand the specifications.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 09:17:15 pm

Not to mention it is difficult to look at spec sheets when they don't download properly. I wish website designers wouldn't require special "somethings" in order to use their sites.....
I don't have anything "special" on my computer-just the normal stuff-whatever that is.

Are you trying to use something "special" or different"

It would be nice to know what operating system-what browser you are using so problems like this can be addressed.  without that knowledge-there is no way to even think about looking at the problem.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Sammy Barr on October 05, 2014, 09:19:30 pm
The QWs are very good subs and match very well with the qw4s. I used that setup today and they sounded great. The VR is better still. Easier to move, more internal bracing, better drivers. Both speakers are reasonably priced and are very durable.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 09:23:36 pm
Agree, and FWIW I don’t think its good practice either, just about every other manufacture specifies 1 watt per meter referenced to the nominal impedance. E.g. - 2.83 volts for 8 ohms and 2.0 volts for 4 ohms.

We measure how powerful speakers (and amplifiers) are in watts, and it’s logical to compare their efficiency relative to watts.
 
I understand impedance, and all the issues Ivan discusses.  I just think what Danley is doing can be misleading, especially for those people who don’t fully understand the specifications.
I would argue that specs without measured responses are MUCH MORE misleading.

We state the measurement condition-the voltage-show the impedance curve-the freq response etc.

If somebody does not understand these simple things-then maybe they should-if they are going to be in this business.

Amps-speakers-impedance etc can be very intertwined and there are lots of things that can easily mislead people (such as stating the -3dB point that is no where near the actual freq stated-ora sensitivity measured outside of the intended bandwidth), but yet people just "swallow it hook line and sinker" without questioning it or actually measuring it.

Why does little or not data seem to impress people?  I would be more concerned about no specs-than specs that are stated pretty well.

But that is just me.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 05, 2014, 09:24:18 pm
I don't have anything "special" on my computer-just the normal stuff-whatever that is.

Are you trying to use something "special" or different"

It would be nice to know what operating system-what browser you are using so problems like this can be addressed.  without that knowledge-there is no way to even think about looking at the problem.
Just Apple Safari, v 5.1.10, Mac OSX 10.6.8, iMac G5, 2.4GHz Intel Core 2 Duo, 2GB RAM. Clicked on the link you posted, that screen shot is the result.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tom Danley on October 05, 2014, 09:25:53 pm
My classic rock band has been in the market for subs for the past 6 months, but every time we think we know what we want we find out about another sub that may work better for us.  We have Peavey QW4 for mains.  One of the main problems is that we can't find anywhere to listen to most of the subs, let alone A/B them.  We have looked at Peavey QW218, then VR 218, JBL SRX 728, STX 828, EV Qrx 218, Yorkville LS 1208, LS 2104 (which seems to be a real good sub on paper, but we can't find much information about it) Danley TH 118 and JTR Orbit Shifter.  My impression from reading comments on the internet is that the Danley may be a cut above the rest.  The sensitivity is listed at 108db 1w 1m.  Does this mean that it would take only 25% of the power to produce the same spl as a sub with 102db sensitivity? (or am I not understanding the 3db=2x the power rule).  Saving on power amps would certainly be a plus.  Right now we are leaning towards new VR 218 or used TH118.  We would appreciate some help from any of you who have heard these subs.

thank you

Hi Mark
Compare as many of your choices side by side if you can with the variety of music you will play. This is far and away the best way to get a feel for the differences in sound quality and output of your choices.               Be skeptical of spec sheets as some are more wishful marketing than technical information and ultimately it’s what something does in your application that matters. Bang for the buck.

Hi David
Yes we use 2.8V as it is easy to measure where 1 Watt (the engineering Watt a measure of power or work, not loudspeaker watt) is difficult and depends on the impedance at that frequency.  The rest of our audio chain from the microphone to amplifier gain is Voltage referenced system and so is a more logical choice in a Synaudcon / engineering frame of reference. 

“Most of my use for spec sheets anymore is to find out how much something weighs, so I can tell someone else how heavy it is so they can lift it for me... And to maybe get an idea of how to power something.”

This spec issue is exactly why I believe it’s important to have a more technical information, not just for how much it weighs but also what It does acoustically.     The idea is to use the same criteria one might find in the specification of a transistor or fastener where one can design something using that engineering information.       Sure there are companies that don’t supply anything other than size and weight, many don’t supply response curves, no impedance curve, some even over state the actual usable SPL by 10 or more times and so on.
     
Maybe that is “what we need to do” to be “comparable” in this market, but it is not something I want to do, I had been sure what we should do is provide more information and for those who can interpret it, even a response curve taken in repeatable conditions.

The point is being able to design based on that information, for example, if you measure a subwoofer at 10 meters and calculate the 1m sensitivity, you have a figure which will allow the SPL to predicted at say 50 or 100 meters while an actual sensitivity curve taken at 1 meter for a large subwoofer may be off at larger distances.
 
“But typically I already know that from the last job.”

And unless one has some kind of technical information regarding what the thing does, that only tells you about what was used in the last job, it does not allow one to compare one thing to another.  Unless one is spending some ones else’s money, somewhere close to the surface should be the bang for the buck concern.   Short of a side by side comparison of two choices, the technical data is the only thing one has.

“You can't tell how good a speaker sounds from a spec sheet. I have heard speakers with really good specs sound really bad.”

One of Richard Heysers lifelong goals was to tie what one measured to what one heard and he never arrived at the “transform” he was looking for.  Part of the problem there is our “sense of hearing” is also tied into what you see and what you know.   
There are also plenty of uses for loudspeakers that are not faithful but sound acceptable even right.     

On the other hand, if / when one is trying to find a signal faithful loudspeaker, the same approach that was used in the past will work here. Listen to a loudspeaker through a measurement grade microphone through good headphones or go a step farther and make a generation loss recording outdoors.  When you find a loudspeaker that can survive just two or three generations before sounding bad, you will have a fine sounding speaker for music and voice reproduction, “signal faithful”. 

 Ray, that is really weird, if you can tell me what you viewed that with, I would like to pass that on the the web site people, clearly that if funky.

Bob, if a single ended subjective assessment is “enough”, there is no need to compare to anything else. if not, then there might be a reason to compare to other possibilities some of which work on different principals and have different acoustic signatures and responses. 

Hi Peter
I am not sure you see what Ivan sees, he measures a lot of loudspeakers, has set up and tuned well over a thousand large installations with many brands of products and taken a bunch of Synaudcon / engineering classes and that is part of what drives him crazy about loudspeaker specs and stuff.  Be glad he can’t talk about specific cases he has run into.   Fwiw,  I have seen loudspeakers who’s impedances dip way below 5 Ohms and yet are still specified as a nominal 8 ohm impedance. 
What is more misleading supplying an impedance curve or saying a speaker that even touches 4 Ohms is an 8 ohm load?         
What conveys more engineering information an impedance curve showing the peaks and dips or a single number?
Given how few people measure anything nowadays, i wonder how important it is to provide engineering information?. 
Best,
Tom Danley
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 05, 2014, 09:27:18 pm
I would argue that specs without measured responses are MUCH MORE misleading.

We state the measurement condition-the voltage-show the impedance curve-the freq response etc.

If somebody does not understand these simple things-then maybe they should-if they are going to be in this business.

Amps-speakers-impedance etc can be very intertwined and there are lots of things that can easily mislead people (such as stating the -3dB point that is no where near the actual freq stated-ora sensitivity measured outside of the intended bandwidth), but yet people just "swallow it hook line and sinker" without questioning it or actually measuring it.

Why does little or not data seem to impress people?  I would be more concerned about no specs-than specs that are stated pretty well.

But that is just me.

well, I think it could be likened to when you buy a car-- do you shop based on horsepower or MPG? Both measure the output or efficiency of the car's engine, just in different ways... they're both useful numbers, just not really interchangeable. MPG can vary based on external conditions, but horsepower is constant-- but people understand MPG better.

Tom, thanks for the shoutout (woo hoO!) -- see my post replying to Ivan. Not sure what happened. But those are my specs there-- nothing TOOO far out of date.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 05, 2014, 10:01:20 pm
well, I think it could be likened to when you buy a car-- do you shop based on horsepower or MPG? Both measure the output or efficiency of the car's engine, just in different ways... they're both useful numbers, just not really interchangeable. MPG can vary based on external conditions, but horsepower is constant-- but people understand MPG better.


I would argue that many buy on horsepower alone.  It depends on what you are looking for and who you are looking to impress with the numbers.

And horsepower alone does not tell how fast a car will go.  It depends on many factors-the weight-aerodynamics-transmission just to name a few.

I would also argue that many people "talk" about watts-but really do not understand what they are saying (but they think they do).

The market just loves those people and they market based on watts.  How many times do you see adds talking about watts vs how many based on usable SPL?

And when I say "usable" I remember one product a few years ago that had a really really high SPL number as the main advertising item.  But the issue was that this figure came from a single peak in the response of the HF driver.  The woofers max SPL was something like 18dB lower.

YEAH-that is what I want-a HF that is 18dB louder than my woofers.  I guess if you have severe hearing loss----------Say what????????

And they are not the only company that does this type of marketing.  Yes they are probably "telling the truth" but not a "useful truth". 

But that does not keep "people who should know better" from going around stating these specs and not even listening to other products because "they can't get as loud".  Yeah-but neither can the product in question-in a "useful" way.

The market understands that most people are stupid when it comes to this-and they simply give them what they "want" to hear/believe.  That is not limited to our industry either.

That does not mean it is right-or useful-but it does help sell product and that is all they are looking for. 

I am sorry to rant about things like this-but it just CONSTANTLY amazes me the number of people that I talk to-see online etc that use these "useless or misleading numbers" as a means to attempt to compare product performance.

And they think they are being "smart" about it. :(  and they somehow convince others who further lower the overall knowledge level and understanding.

Together we can help "raise the bar" to hopefully improve the overall quality of sound and expectations.

But there will be people who still believe you can get a 2,000 watt sound system that runs off of 8 D cell batteries and has some 6" speakers-----------------

No wonder some manufacturers feel like this is "shooting fish in a barrel".
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mark Monson on October 05, 2014, 10:08:05 pm
Really Ivan, WTF, does every reply have to be a sermon?

OP,
Any of the subs you listed will do a decent job for you. I would look towards the SRX728 which are obsolete, but can be found, and will do a very good job. The only thing you may not like about the 728 is the size and weight, but it is a formidable dual 18" cabinet that many of us rely on with great success and very, very few failures. The STX 828 is also a great sub with the same capabilities as the 728. The drivers are not the same, and the 2242 used in the 828 will produce good quality sound at slightly lower frequencies than the 728, but either sub will produce very high quality sound capable of rolling your socks up and down at high levels.


Bob - Thank you for the concise understandable reply.  Thanks to the rest of you for showing me that there is more to this than is first apparent.  It seems like rating subs is a little like religion.  Since I can't hear all of the subs I'm considering, I'll have to decide where to put my "faith"

After reading a lot of opinions regarding high end subs, my impression is that the ones I've listed fall into 3 categories

Good                   db/1w/1m
Peavey QW 218   100
EV QRX 218         102
Yorkville 1208      105

Better
Peavey VR 218   100
JBL SRX 728       98
JBL STX 828       98
Yorkville 2104     98

Best
Danley TH 118   108
JTR Orbit shifter  103

Could those of you who have heard these subs comment on my grouping?  I am leaning towards VR 218 or SRX 728 (If I can find some used).  If the Danley TH 118 is truly a significant step up and if it requires less w/spl (something that is suspect after reading the above posts) then we would probably buy one now and save up to purchase another later.

Again, I appreciate all of the knowledgeable people who are commenting on this

Title: Re: Which subs to buy? Paralysis by analysis
Post by: Peter Morris on October 05, 2014, 11:46:15 pm
I would argue that specs without measured responses are MUCH MORE misleading.

We state the measurement condition-the voltage-show the impedance curve-the freq response etc.

If somebody does not understand these simple things-then maybe they should-if they are going to be in this business.

Amps-speakers-impedance etc can be very intertwined and there are lots of things that can easily mislead people (such as stating the -3dB point that is no where near the actual freq stated-ora sensitivity measured outside of the intended bandwidth), but yet people just "swallow it hook line and sinker" without questioning it or actually measuring it.

Why does little or not data seem to impress people?  I would be more concerned about no specs-than specs that are stated pretty well.

But that is just me.

Ivan, nobody is talking about your competition not supply all the information, why did you assume that; most supply frequency response, impedance curves and polar information etc etc.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Peter Morris on October 06, 2014, 12:45:58 am
Hi Mark
Compare as many of your choices side by side if you can with the variety of music you will play. This is far and away the best way to get a feel for the differences in sound quality and output of your choices.               Be skeptical of spec sheets as some are more wishful marketing than technical information and ultimately it’s what something does in your application that matters. Bang for the buck.

Hi David
Yes we use 2.8V as it is easy to measure where 1 Watt (the engineering Watt a measure of power or work, not loudspeaker watt) is difficult and depends on the impedance at that frequency.  The rest of our audio chain from the microphone to amplifier gain is Voltage referenced system and so is a more logical choice in a Synaudcon / engineering frame of reference. 

“Most of my use for spec sheets anymore is to find out how much something weighs, so I can tell someone else how heavy it is so they can lift it for me... And to maybe get an idea of how to power something.”

This spec issue is exactly why I believe it’s important to have a more technical information, not just for how much it weighs but also what It does acoustically.     The idea is to use the same criteria one might find in the specification of a transistor or fastener where one can design something using that engineering information.       Sure there are companies that don’t supply anything other than size and weight, many don’t supply response curves, no impedance curve, some even over state the actual usable SPL by 10 or more times and so on.
     
Maybe that is “what we need to do” to be “comparable” in this market, but it is not something I want to do, I had been sure what we should do is provide more information and for those who can interpret it, even a response curve taken in repeatable conditions.

The point is being able to design based on that information, for example, if you measure a subwoofer at 10 meters and calculate the 1m sensitivity, you have a figure which will allow the SPL to predicted at say 50 or 100 meters while an actual sensitivity curve taken at 1 meter for a large subwoofer may be off at larger distances.
 
“But typically I already know that from the last job.”

And unless one has some kind of technical information regarding what the thing does, that only tells you about what was used in the last job, it does not allow one to compare one thing to another.  Unless one is spending some ones else’s money, somewhere close to the surface should be the bang for the buck concern.   Short of a side by side comparison of two choices, the technical data is the only thing one has.

“You can't tell how good a speaker sounds from a spec sheet. I have heard speakers with really good specs sound really bad.”

One of Richard Heysers lifelong goals was to tie what one measured to what one heard and he never arrived at the “transform” he was looking for.  Part of the problem there is our “sense of hearing” is also tied into what you see and what you know.   
There are also plenty of uses for loudspeakers that are not faithful but sound acceptable even right.     

On the other hand, if / when one is trying to find a signal faithful loudspeaker, the same approach that was used in the past will work here. Listen to a loudspeaker through a measurement grade microphone through good headphones or go a step farther and make a generation loss recording outdoors.  When you find a loudspeaker that can survive just two or three generations before sounding bad, you will have a fine sounding speaker for music and voice reproduction, “signal faithful”. 

 Ray, that is really weird, if you can tell me what you viewed that with, I would like to pass that on the the web site people, clearly that if funky.

Bob, if a single ended subjective assessment is “enough”, there is no need to compare to anything else. if not, then there might be a reason to compare to other possibilities some of which work on different principals and have different acoustic signatures and responses. 

Hi Peter
I am not sure you see what Ivan sees, he measures a lot of loudspeakers, has set up and tuned well over a thousand large installations with many brands of products and taken a bunch of Synaudcon / engineering classes and that is part of what drives him crazy about loudspeaker specs and stuff.  Be glad he can’t talk about specific cases he has run into.   Fwiw,  I have seen loudspeakers who’s impedances dip way below 5 Ohms and yet are still specified as a nominal 8 ohm impedance. 
What is more misleading supplying an impedance curve or saying a speaker that even touches 4 Ohms is an 8 ohm load?         
What conveys more engineering information an impedance curve showing the peaks and dips or a single number?
Given how few people measure anything nowadays, i wonder how important it is to provide engineering information?. 
Best,
Tom Danley

Hi Tom,

I understand all of that, but have a look at Marks post (25). He has assumed your TH118 is rated @ 108 1w/m - its not, its 105 w/m - ref 2 volts @ 4 ohm. The other boxes he is comparing them with are also 4 ohms ref. 2.0 volts. That happened even after David pointed how your boxes are measured.

... and that's an example of my point, and exactly why I think what you are doing with your specifications is misleading.

Don't get me wrong I'm not suggesting that these are not excellent products, in fact I would love some TH118s  :) and it does not change how they perform ... I believe you should specify your box efficiencies with respect to their nominal impedance like everyone else- i.e. 8 ohms ref. 2.83Volts -  4 ohms ref. 2.0 volts.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mario Pollio on October 06, 2014, 06:34:10 am

Not to mention it is difficult to look at spec sheets when they don't download properly. I wish website designers wouldn't require special "somethings" in order to use their sites.....

I have a macbook pro and it does the same thing also when clicking on spec sheets on Danley's website. If you google the product and click on the spec sheet through a google search, for some reason it works.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 09:05:15 am
Ivan, nobody is talking about your competition not supply all the information, why did you assume that; most supply frequency response, impedance curves and polar information etc etc.
Sorry, but I would argue that most don't supply that information.

Some do, but most-or at least many (I guess it depends on who falls into the "most" category) do not.

Or some may provide it for some models-but not others.

And we won't even go into how much smoothing and such is used---------------
Title: Re: Which subs to buy? Paralysis by analysis
Post by: David Sturzenbecher on October 06, 2014, 09:09:38 am
I think what Peter is getting at is that your argument to.." Your specs are misleading" is "but there not as misleading as the other guys!"


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Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 09:24:31 am
well, I think it could be likened to when you buy a car-- do you shop based on horsepower or MPG? Both measure the output or efficiency of the car's engine, just in different ways... they're both useful numbers, just not really interchangeable. MPG can vary based on external conditions, but horsepower is constant-- but people understand MPG better.


The automotive industry has strict (or so I am lead to believe-but not positive) guidelines for testing and for specs.

All our industry has is "some suggestions", and every manufacturer can test however they want-publish whatever they want-as little or as much as they want there is no "agency" that makes sure those specs are correct.

I would love to have something like this-but there simply is not enough money in our industry to warrant it.

So manufacturers are free to do/publish whatever they want.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 09:27:24 am
I think what Peter is getting at is that your argument to.." Your specs are misleading" is "but there not as misleading as the other guys!"


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It is only misleading if you don't understand enough about the subject.

I will STILL argue that the "1 watt" is very misleading" since often the actual power is more or less than 1 watt.

But people are free to think what they want to.

I am just hoping that some people will gain a little bit better understanding into what is REALLY going on.

"A educated consumer is a good customer". To steal a marketing line----------
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 09:40:52 am
Hi Tom,

I understand all of that, but have a look at Marks post (25). He has assumed your TH118 is rated @ 108 1w/m - its not, its 105 w/m - ref 2 volts @ 4 ohm. The other boxes he is comparing them with are also 4 ohms ref. 2.0 volts. That happened even after David pointed how your boxes are measured.

... and that's an example of my point, and exactly why I think what you are doing with your specifications is misleading.

Don't get me wrong I'm not suggesting that these are not excellent products, in fact I would love some TH118s  :) and it does not change how they perform ... I believe you should specify your box efficiencies with respect to their nominal impedance like everyone else- i.e. 8 ohms ref. 2.83Volts -  4 ohms ref. 2.0 volts.

So how would you suggest we "present" something that is not a standard impedance-such as our Th115 (in the "4" ohm version).  The actual impedance should be rated at 5 ohms-but 4 is the closest standard value.

If 2V was used-then there is a fair bit less input level than what would be "1 watt" with a normal number-so the specs would be lower than what they should be (for 1 watt).

If we used a voltage that would be "1 watt" with 5 ohms", then the SPL number would be "right" but the drive voltage would not be a standard voltage-so a large number of people would be "confused" by this odd voltage-but the voltage would be  correct.

And that brings us to another point.

What IS the standard impedance?  yes it varies-but how is a simple number determined?

If you were to use the "odd voltage" but being what might be considered "1 watt", how do you determine that number?

Is it some sort of average?  How is that average determined?  by impedance at a particular Hz and average it that way?

Or would it be per octave? 

How do you determine the freq range to get this average?  What is the low freq point?  the high freq point?

As you can see-it can get a lot more complicated and confusing REAL quick.

That is PRECISELY the reason we use a SINGLE voltage (yes it does correspond to 1 watt into 8 ohms) for all of the cabinets-to keep it simple (at least in our minds)

As my tag line goes: A simple answer to a complex question is wrong.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 09:45:44 am
Just Apple Safari, v 5.1.10, Mac OSX 10.6.8, iMac G5, 2.4GHz Intel Core 2 Duo, 2GB RAM. Clicked on the link you posted, that screen shot is the result.
I have passed that information on to the guys that are charge of the website.

I have NO idea or opinion in that world.

Thanks for the information-I had no idea that there was an issue.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 06, 2014, 10:10:56 am
Really Ivan, WTF, does every reply have to be a sermon?


Partly because there is sooo much confusion out there, and not everybody has the ability or has been exposed to what is really going on.

Sometimes it takes a bit of explanation to help people understand.

Or to put it in a different way:

What if somebody said that a modern Fender 40 watt with a 12" is the same as a 70s which is just like a pre CBS Fender.

I bet you could not explain it in just a few words so that a novice cold understand it.

It all depends on where your passion is at-how important is it and so forth.

To some people some things are more important than others. 

It IS important to understand where "the numbers" come from and how they are different and why.  At least to me anyway------------

Numbers without anything to back them up-are pretty useless-in my opinion anyway.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 06, 2014, 10:48:14 am
Partly because there is sooo much confusion out there, and not everybody has the ability or has been exposed to what is really going on.

Sometimes it takes a bit of explanation to help people understand.

Or to put it in a different way:

What if somebody said that a modern Fender 40 watt with a 12" is the same as a 70s which is just like a pre CBS Fender.

I bet you could not explain it in just a few words so that a novice cold understand it.

It all depends on where your passion is at-how important is it and so forth.

To some people some things are more important than others. 

It IS important to understand where "the numbers" come from and how they are different and why.  At least to me anyway------------

Numbers without anything to back them up-are pretty useless-in my opinion anyway.
Bob is saying what some (like me ) were thinking too. I have teased you before about your "last honest man in Dodge City" speech. Yes there will always be some fraction of the marketers making unqualified FAB claims, but this is not always because of malfeasance. Some will be from ignorance or misunderstanding, and some is the nature of salesmen polishing the turds they have to sell. The customers contribute to specification abuse as they make purchase decisions with poor understanding of what exactly the specs mean.

I just re-read you white paper on specs on your website and it seems to address only briefly a couple aspects of speaker specifications. I realize you are busy, but perhaps adding some meat to the specifications white paper, and then linking to that when we hear these questions repeated over and over.

Ivan I feel your pain and have heard some very similar complaints from Peavey speaker engineers and product mangers complaining about competitor's dishonest specs. Speakers are complicated with multiple moving parts that will always be difficult for consumers to grasp. The human condition is to attach onto one or two narrow factors at most and ignore the rest (kind of like politics).

All we can do is do what we know is right, but you might save yourself some time repeating yourself, with a more comprehensive white paper on how you specify loudspeakers.   

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tim Tyler on October 06, 2014, 01:07:11 pm
Mark,

I have experience with the  QW218, Versarray 218, JBL SRX728.  The QW and the SRX are essentially comparable, the SRX seems to be "voiced" a little lower to my ear, but when pushed to performance limitations, not much difference in output, I prefer the QW due to lower cost and field replaceable baskets for the drivers.  The QW4 sitting upright on the QW218 is a perfect physical match.  The Versarray 218 is a significant step up from these speaker in low output and loudness, (1200 watt vs 800 watt drivers) but you will need high output power amps to achieve full performance, think 4k watts or more at 4 ohms.

I used the LS1208 for a couple of years, they are big, I didn't find them very detailed or musical sounding, never directly compared them to the above boxes.

Now back to the hijackers ... ;D

-Tim T
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Spenser Hamilton on October 06, 2014, 02:07:31 pm
I prefer the QW due to lower cost and field replaceable baskets for the drivers.

Oddly enough I prefer the 728 because I've never lost a driver.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 06, 2014, 02:48:12 pm
Oddly enough I prefer the 728 because I've never lost a driver.

.. yeah, that's a good point. I've been using 728s since -- I think I first bought them in 2006? -- and I also have never lost a driver on one.

-Ray
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Sammy Barr on October 06, 2014, 04:48:34 pm
I have owned both the QW and the VR.  Both are great subs.  The VR would be my choice but I am using The QW4 over QW218 as one of my systems.  I drive the Qw subs with a Peavey IPR 7000 and am getting great results, plenty of sub without ever hitting the limiter. I highly recommend either sub.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Peter Morris on October 06, 2014, 10:43:08 pm
To put some perspective on this debate – the question /argument boils down using 2.83 volts to rate a speaker’s efficiency irrespective of its nominal impedance - the Danley method; or using 2.83 volts for 8 ohm and 2.0 Volts for 4 ohms – everyone else. Its not really much of an issue so long as you understand the implications.

What's important when testing or comparing a bunch of speakers that you compare apples with apples.
 
In this case for example, the Peavey QW 218 100, EV QRX 218 & JBL SRX 728 all had 4 ohm motor assemblies as did the Danley TH118. They were all tested with 2 volts except the Danley that was tested 2.8s volts.

They should all be tested with the same input voltage if you want to compare them. The solution is to just take 3 dB off the TH118 SPL plot before you compare.

If we now look at Ivan’s argument about the real impedance not being exactly 4 or 8 ohms and look at the real impedance curves (links below) you will see that between 40 and 80Hz (the nominal operating range for a sub) that  the TH118 will place a much greater load on your amplifier than the reflex loaded speakers.  The TH118 actually drops to 3 ohms at 67 Hz compared to the QW218 which is about 10 ohms at this frequency. Two TH118 speakers = 1.5 ohms @ 67Hz! Given this is right in the middle of its intended operating range I struggle to accept its nominal impedance being listed as 4 ohms but it’s probably OK...just.

I can’t find the impedance curve for the JBL, which is one of Ivan’s issues which I completely agree with.  They should publish it, however its reflex loaded sub and its impedance curve will be similar to the Peavey and EV. Its worth mentioning that the driver and the box type / alignment determine the impedance. I must also say I was impressed with Peaveys specifications in that they included 2nd and 3rd harmonic distortion plots!

The other thing to note is; some of the specifications listed in this thread are whole space measurements and some ½ space. There is quite a difference ... 6 dB - see attached link.

I hope this adds something positive to the paralysis analysis discussion.

http://assets.peavey.com/literature/specs/00571310_3.pdf
http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/04/TH-118-spec-sheet.jpg
https://www.trueaudio.com/st_spcs1.htm
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 07, 2014, 09:40:17 am
The TH118 actually drops to 3 ohms at 67 Hz compared to the QW218 which is about 10 ohms at this frequency. Two TH118 speakers = 1.5 ohms @ 67Hz! Given this is right in the middle of its intended operating range I struggle to accept its nominal impedance being listed as 4 ohms but it’s probably OK...just.



The other thing to note is; some of the specifications listed in this thread are whole space measurements and some ½ space. There is quite a difference ... 6 dB - see attached link.


I have not looked at the curves of the other speakers-but will comment that it is VERY COMMON to use LOTS of smoothing to present a freq or impedance graph.

When you use smoothing-the peaks and dips get "rounded off" so they do not appear as high or as low as they actually are.

So it depends on where the numbers come from-a smoothed response or the actual response.

And when "smoothing" there are several different methods and sometimes both are used-so it is hard to know what is exactly going on. 

First is the number of data points used.  If a data point is not present at the particular dip-then that dip simply does not show up on the plot-even if it is actually there.

Then there is the smoothing of the overall plot.

A real loudspeaker has lots of ripples.  Yes we have to use smoothing to make it make sense-but how much and where is the real question-and different people have different answers.

I have a problem with any measurement with subs in "whole space".  yes it may be a "measurement", but where in real life is that ever going to take place?

An before you answer "flown subs", consider this.  Where is the AUDIENCE?????????

In most cases they are on the ground or on a large surface.  Most people do not listen to a sound system when they are standing on a 30' ladder.

So with the audience on the ground-THEY are in a half space situation-so the half space loading IS in effect-even if the subs are flow.

It does not matter if the subs are flown or not-you only get the half space loading ONCE.

So I don't see any condition in real life that a whole space measurement would be used.

Now I am talking about subs for this-because the wavelengths are so long that the space the average person is away from the boundary really doesn't matter.

With full range speakers it is a different situation in that the wavelengths are much shorter (at the higher freq) so a whole space condition is a good starting point.

If you put a full range speaker in a half space condition then the response will get '[skewed" by the lower freq having additional loading of the boundary, but the higher freq or those controlled by the horns will not get any additional level.  As evidenced in the Peavey link you provided-the higher freq don't change with the loading.

Of course it also depends on the freq involved-the spacing from the boundary etc as to how much additional (or cancellation) is going on.

Once again-it is not always as simple as it looks or as people would like it to be
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Chuck Simon on October 07, 2014, 11:20:30 am
"An before you answer "flown subs", consider this.  Where is the AUDIENCE?????????
In most cases they are on the ground or on a large surface.  Most people do not listen to a sound system when they are standing on a 30' ladder."

That is a great point and one I don't think I have ever seen written before.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tim McCulloch on October 07, 2014, 11:40:09 am
"An before you answer "flown subs", consider this.  Where is the AUDIENCE?????????
In most cases they are on the ground or on a large surface.  Most people do not listen to a sound system when they are standing on a 30' ladder."

That is a great point and one I don't think I have ever seen written before.

Ivan is saying the *audience* is in half-space and benefits from the ground plane loading even if the speakers are in full space.  The statement is not stand-alone and requires this context to be evaluated correctly.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 07, 2014, 12:05:52 pm
  The statement is not stand-alone and requires this context to be evaluated correctly.
As do most statements in audio.  You have to look at more than just a single point.

hence the complexity of the subject-just like impedance-watts-sensitivity-coverage pattern and so forth.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Scott Shaw on October 07, 2014, 02:57:40 pm
I have owned both the QW and the VR.  Both are great subs.  The VR would be my choice but I am using The QW4 over QW218 as one of my systems.  I drive the Qw subs with a Peavey IPR 7000 and am getting great results, plenty of sub without ever hitting the limiter. I highly recommend either sub.

I've been running the QW218 for about 13 years now, pushing them with a QSC PLX-3402 bridged into each sub. They sound great and I've never had a cone failure.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Doug Fowler on October 07, 2014, 03:12:08 pm
.. yeah, that's a good point. I've been using 728s since -- I think I first bought them in 2006? -- and I also have never lost a driver on one.

-Ray

Two reasons the local large regional went with 30ish SRX728 to use with their X-Array rig:

1.  Crazy low price for the quality.
2.  Being a JBL repair center, they had never seen one in for a recone. 

I spoke with someone in JBL management about the price for 728 in a casual conversation and he said they had come to realize it was under priced. STX began showing up not long after that. 

fwiw
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Bob Leonard on October 07, 2014, 04:36:49 pm
I was with our good friend "CT" and while in his shop he showed me a pair of drivers taken from either a 718 or 728, I don't remember which. The drivers were destroyed in a manner I had never seen, not in 45 years. "CT" told me they came from subs used by a DJ, and it was not the first time he had re-coned the drivers for him. Other than that I have not heard of anyone with problems with the SRX subs, myself included.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 07, 2014, 04:53:38 pm
I was with our good friend "CT" and while in his shop he showed me a pair of drivers taken from either a 718 or 728, I don't remember which. The drivers were destroyed in a manner I had never seen, not in 45 years. "CT" told me they came from subs used by a DJ, and it was not the first time he had re-coned the drivers for him. Other than that I have not heard of anyone with problems with the SRX subs, myself included.
Damn. That has to take some serious concerted effort. I mean granted I remember being surprised when a friend blew up Mackie 450s, after always believing they would thermal shutoff before any damage occurred yet here he was...

I guess part of me needs to be "Charlie, come on, teach the guy how to not blow up his rig," but the business man in me sees the reconing/repairs as a nice steady source of revenue. :)

-Ray
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Bob Leonard on October 07, 2014, 05:00:34 pm
Believe me Ray, "CT" was all over this guy and nothing helped. Some people just can't take a hint. The voice coils looked like a ball of steel wool. Can you imagine how much abuse they must have sustained before letting go?
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tim McCulloch on October 07, 2014, 05:28:57 pm
Damn. That has to take some serious concerted effort. I mean granted I remember being surprised when a friend blew up Mackie 450s, after always believing they would thermal shutoff before any damage occurred yet here he was...

I guess part of me needs to be "Charlie, come on, teach the guy how to not blow up his rig," but the business man in me sees the reconing/repairs as a nice steady source of revenue. :)

-Ray

The kind of silliness Bob is talking about is why many of us in live sound (who've figured out how to not blow up speakers after the first or second recone) think most DJ's are a lower life form.  For those that achieve this dubious level of "professionalism" there is no effective education... except for the reconer, who gets to see new and exciting damage.

/cynicism, sarcasm, satire
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 07, 2014, 05:45:17 pm
The kind of silliness Bob is talking about is why many of us in live sound (who've figured out how to not blow up speakers after the first or second recone) think most DJ's are a lower life form.  For those that achieve this dubious level of "professionalism" there is no effective education... except for the reconer, who gets to see new and exciting damage.

/cynicism, sarcasm, satire
I have seen plenty of "unbelievable" damaged speakers-including many that I did to myself.  Including my first rap show that I thought I was "being smart" but forgot that when I bridged the amps the gain went up 6db, and did not reset my limiters. OOPS

During the first act I lost ALL of my 18" subs.  Luckily I had a lot of 15" bass drivers and we got by.

Now as a starting point for all "bass heavy" shows I start with the limiters at 1/2 continuous power rating.

So far this has worked well-even when the limiters are buried and never come out of limit.

And it can happen to anybody.  There is a well respected person on the forums (I will not mention any names) who brought me a driver that he SERIOUSLY tore up by accident.

It was a B&C 18SW115 that he was running with 14,000 watts and had a "boo boo".

He was actually laughing about how "good" of a job he had done to it.

The reason I got into reconing in the first place was to save myself money on recones.

I have easily reconed a couple hundred of my own speakers.  Of course this was decades before DSPs and limiters were not was easy to come by (at least in the market I was in)  or understood back then-like they are today.

I haven't torn up a loudspeaker in many years now.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: duane massey on October 07, 2014, 10:10:05 pm
Amazing how this thread went from a standard "what sub should I choose" to a fascinating discussion/debate that ANYONE who thinks they know how to read specs should read over and over.
This topic has always been a sore spot for me, as I tried (many years ago) to generate some accurate honest specs on a sub design I was building. After attempting to research the methodology that the "big boys" were using I came to the conclusion that there were no standards, just massaged numbers that marketing could print and consumers would accept. I finally gave up after realizing that there was no real way to make honest comparisons. I continued to build (and sell) the boxes, just quit trying to market them. I agree with just about everything Ivan and Tom have said here, but I also agree with the thought that the final test has to be "How do they sound?"
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 08, 2014, 07:37:58 am
Amazing how this thread went from a standard "what sub should I choose" to a fascinating discussion/debate that ANYONE who thinks they know how to read specs should read over and over.
This topic has always been a sore spot for me, as I tried (many years ago) to generate some accurate honest specs on a sub design I was building. After attempting to research the methodology that the "big boys" were using I came to the conclusion that there were no standards, just massaged numbers that marketing could print and consumers would accept. I finally gave up after realizing that there was no real way to make honest comparisons. I continued to build (and sell) the boxes, just quit trying to market them. I agree with just about everything Ivan and Tom have said here, but I also agree with the thought that the final test has to be "How do they sound?"
Agreed.  There is no way specs can describe what you are hearing/perceiving and different people like different things in the way a loudspeaker "sounds".

Specs (if they are semi accurate and contain enough information) can give an indicator if a particular loudspeaker is capable of doing the intended job.  Is it loud enough-does it have the freq response needed-is the coverage correct etc.?

Why do we not use good studio monitors for PA speakers-they "sound" great-but in most cases can't get loud enough. 

If it does not pass that first part of the test-it really does not matter how good it "sounds".  It may be a great tool-but the wrong one for the job.  And different jobs need different tools.

So in my opinion-before the listening begins, you have to "narrow the field" to products that will do the intended job.

The only way to do this is with some decent specs.  Without that-then you HAVE to resort to listening-which is not always easily possible AND measuring/testing them for yourself to determine if they are capable of the job at hand.

I would argue that most people don't have the tools/knowledge to be able to test loudspeakers for suitability to do a particular job.

One thing that is funny to watch.  The next time you go to a loudspeaker demo-see how many stay in one place (in the middle) and listen and then evaluate the loudspeaker.

This is fine if it is a studio monitor with only one listening position.  The people who are doing the REAL evaluation are walking around-often back in forth in one area-listening for the coverage pattern-the response at different angles and so forth.

In most cases we are trying to provide sound for people in a wide area-so what it sounds like in places other than on axis IS important-unless you are the FOH guy and all you care about is yourself-in which you should probably seek other employment since it is your job to provide sound for the AUDIENCE WHO PAYS YOUR SALARY-not to entertain yourself.  You can do that at home---------------.

I really wish there was some standardization that everybody had to follow-but there isn't.  So it is left up to the individual manufacturer to provide information they feel is useful to helping people choose their product.

Without information-we are left in "believe land" where you are just expected to swallow a little pill and all will be OK and you will swallow and believe whatever is told to you.

That may be fine for some people-but not me.  I believe that if somebody is not telling you something-they are trying to hide the reality.

The nice thing about standards is that there are so many to choose from.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 08, 2014, 09:31:44 am
Just Apple Safari, v 5.1.10, Mac OSX 10.6.8, iMac G5, 2.4GHz Intel Core 2 Duo, 2GB RAM. Clicked on the link you posted, that screen shot is the result.
OK we found out YOUR problem.

What you need to do is to update your Apple Safari to the latest version.

We found somebody running the same general version as you (5) and they had the same issues.

The people who are running V6 or V7 do not have this issue.

I have been told (I am not an Apple guy) that most "Apple guys" do not use Safari-because it is not as good as other browsers.

The only way we found an old one was because the guy who has it does not use Safari and it was just sitting on his computer.

But when he opened the pages-he got exactly what you saw.

Hope this helps.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mac Kerr on October 08, 2014, 10:08:26 am
I have been told (I am not an Apple guy) that most "Apple guys" do not use Safari-because it is not as good as other browsers.

You have been misinformed. Safari is the most popular browser on Mac OS.

Mac
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 08, 2014, 11:28:56 am
Amazing how this thread went from a standard "what sub should I choose" to a fascinating discussion/debate that ANYONE who thinks they know how to read specs should read over and over.
This topic has always been a sore spot for me, as I tried (many years ago) to generate some accurate honest specs on a sub design I was building. After attempting to research the methodology that the "big boys" were using I came to the conclusion that there were no standards, just massaged numbers that marketing could print and consumers would accept. I finally gave up after realizing that there was no real way to make honest comparisons. I continued to build (and sell) the boxes, just quit trying to market them. I agree with just about everything Ivan and Tom have said here, but I also agree with the thought that the final test has to be "How do they sound?"
I have an article in one of my dad's old notebooks that was reprinted from Bell Laboratories Record, May 1929. The article is titled "What's a Good Loud Speaker?" by L.G. Bostwick a Bell Labs researcher. The 5 pages of this article I have talks about things like on-axis and off-axis response, and problems from standing waves when making indoor measurements. Their solution was to put the measurement microphone on a round fixture so the microphone could be rotated on a six foot diameter circle and the readings averaged. 

I suspect measurement technology has improved since 1929.  8)

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 08, 2014, 11:55:43 am
You have been misinformed. Safari is the most popular browser on Mac OS.

Mac
As I said-I am not a Mac person-and just heard from "others who told others" that "other" Mac users  often used other browsers.

I have no experience in this-and it was purely "here-say".

But the problem appears to be with the older version of Safari and not the newer ones.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 08, 2014, 12:00:58 pm
I have an article in one of my dad's old notebooks that was reprinted from Bell Laboratories Record, May 1929. The article is titled "What's a Good Loud Speaker?" by L.G. Bostwick a Bell Labs researcher. The 5 pages of this article I have talks about things like on-axis and off-axis response, and problems from standing waves when making indoor measurements. Their solution was to put the measurement microphone on a round fixture so the microphone could be rotated on a six foot diameter circle and the readings averaged. 

I suspect measurement technology has improved since 1929.  8)

JR
As the saying goes  "the ancients keep stealing our inventions".

Some people move the mic-some move the speaker.

But the issues involved in making measurements have not changed.

I am often amazed at what these guys came up with, with as little as they had to work with.

They were some seriously sharp guys.

It is one thing to make something better or improve it, and quite another to come up with the idea from scratch.

Radio and TV modulation schemes always interested me.

It is not just a matter of transmitting a signal- you also have to be able to receive it and demodulate it back down to a usable format.

I think people had more time on their hands back then-or maybe not----------
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Josh Millward on October 08, 2014, 12:06:42 pm
I have an article in one of my dad's old notebooks that was reprinted from Bell Laboratories Record, May 1929. The article is titled "What's a Good Loud Speaker?" by L.G. Bostwick a Bell Labs researcher...

JR, Could you be persuaded to scan that article and turn it into a PDF? I am absolutely interested in reading it.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 08, 2014, 01:11:54 pm
JR, Could you be persuaded to scan that article and turn it into a PDF? I am absolutely interested in reading it.
According to google there was a full 24 page paper, written by him in 1929 with no scans on the WWW. I only have the first 5 pages. I didn't even read it word for word myself. I just scanned through it to pick out a few key details.

It will be a little confusing if you are not familiar with the 1920's terminology. The microphone was called "transmitter" in one place and a "moving coil receiver" in another.

Maybe if I have nothing better to do, but IMO it is only of vague historic interest. My reason for mentioning is is that we all too often assume the ancients were really ignorant, and they actually did a lot with the tools they had. I can imagine it taking them days to make measurements we do with a single button push.

JR

PS: My dad's old engineering notebooks are full of seemingly trivial by today's standards issues like wow and flutter management in recording/playback machinery.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 08, 2014, 02:04:56 pm
And I forgot to mention these are small format pages (only 3" wide) so my crude scanner will probably not do a great job.

My first try didn't work because this forum doesn't accept PDF uploads and the fules were too large. So here is pages 1,2,3

Arghh if you can't read them you can drive to Hickory and I'll show them to you.

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 08, 2014, 02:09:48 pm
Here's pages 4 and 5

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Bob Leonard on October 08, 2014, 05:22:59 pm
JR,

That's the balls. Thank you for posting those pages.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Cailen Waddell on October 08, 2014, 09:47:43 pm

You have been misinformed. Safari is the most popular browser on Mac OS.

Mac

Which in no way makes it good, but Mac is correct.  That said safari 5.x accounts for .75% of web traffic so....


Sent from my iPhone using Tapatalk
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Josh Millward on October 09, 2014, 11:50:18 am
And I forgot to mention these are small format pages (only 3" wide) so my crude scanner will probably not do a great job.

My first try didn't work because this forum doesn't accept PDF uploads and the fules were too large. So here is pages 1,2,3

Arghh if you can't read them you can drive to Hickory and I'll show them to you.

JR
Thanks JR!

It is a bit tough to read, but I find these older texts interesting. It is always curious to me to see what the folks who came before us did to solve the same problems that we are faced with today.

Seriously, thank you for taking the time to scan and upload! (twice even!)
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mark Monson on October 09, 2014, 01:20:39 pm
Hi Tom,

I understand all of that, but have a look at Marks post (25). He has assumed your TH118 is rated @ 108 1w/m - its not, its 105 w/m - ref 2 volts @ 4 ohm. The other boxes he is comparing them with are also 4 ohms ref. 2.0 volts. That happened even after David pointed how your boxes are measured.

... and that's an example of my point, and exactly why I think what you are doing with your specifications is misleading.

Don't get me wrong I'm not suggesting that these are not excellent products, in fact I would love some TH118s  :) and it does not change how they perform ... I believe you should specify your box efficiencies with respect to their nominal impedance like everyone else- i.e. 8 ohms ref. 2.83Volts -  4 ohms ref. 2.0 volts.


I understand that the Danleys are not rated at db/1w/1m, but I wanted to put something at the head of the column to show I was looking to compare sensitivity.  I think I got an answer to my question.  The Danleys should be considered around 105 rather than 108 when compared to the other speakers.

This discussion has been enlightening to me in that specifications can be manipulated easily if there is a desire to do so.  I remember in the 70's there was controversy on power ratings on amplifiers until there was some agreement (I don't know if it was mandated) on using the RMS system.  It would be great if this discussion could lead to an agreement among speaker manufacturers to use a set of standardized specifications.  It seems we have the brightest minds in the industry participating in this forum including many manufacturers.  Perhaps NAMM (or some other pro sound organization) could come up with a certifying logo that would let the less informed buyer, such as myself, know that the specifications listed were carried out in a manner that they can be compared fairly to other speakers.

Reading the posts to this thread indicates that there is enough passion to accomplish this.

 
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Josh Millward on October 09, 2014, 01:28:19 pm
It would be great if this discussion could lead to an agreement among speaker manufacturers to use a set of standardized specifications.  It seems we have the brightest minds in the industry participating in this forum including many manufacturers.  Perhaps NAMM (or some other pro sound organization) could come up with a certifying logo that would let the less informed buyer, such as myself, know that the specifications listed were carried out in a manner that they can be compared fairly to other speakers.

Reading the posts to this thread indicates that there is enough passion to accomplish this.

It has already been done.

Common Loudspeaker Format: a.k.a. CLF
All the information you ever wanted to know about a loudspeaker in one easy to understand and comprehensive format.
You can learn more about it at their website: http://clfgroup.org/ (http://clfgroup.org/)

However, you need to make it a requirement from your loudspeaker manufacturer.

Also newly available is Common Amplifier Format: a.k.a. CAF
Learn more about this at their website: http://cafgroup.org/ (http://cafgroup.org/)
Demand that your amplifier manufacturers provide CAF documentation with their amplifiers.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 09, 2014, 01:52:18 pm
But the problem appears to be with the older version of Safari and not the newer ones.

*sighs* the age old fight against web developers who insist on having the latest and greatest widgets and gizmos on their websites thus obsoleting perfectly good computers. Woo hoo! I just miss the good ole' days where the majority of web developers preferred clean, compatible and super fast websites, and gave the option for cutting edge if people wanted it, but it wasn't forced on everyone.

But I know, I am absolutely in the minority as I regard the internets as a tool to assist me with me life, as opposed to having a life intertwined with and entirely dependent on the internet.

-Ray "Day Late and a Dollar Short to the discussion" Aberle
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Mark McFarlane on October 09, 2014, 02:39:47 pm
*sighs* the age old fight against web developers who insist on having the latest and greatest widgets and gizmos on their websites thus obsoleting perfectly good computers. ...

FWIW the Danley spec sheet isn't a web page, it's a pdf document. Blame Adobe for changing pdf too frequently.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ray Aberle on October 09, 2014, 02:55:59 pm
FWIW the Danley spec sheet isn't a web page, it's a pdf document. Blame Adobe for changing pdf too frequently.

Which is my point. Forcing the world to constantly update. Like Flash, also an Adobe (now) product. My Powerbook G5 no longer will run it because they've updated it-- rather then let me not experience the best possible stuff, they just block it so it doesn't work *at all* until it's upgraded.

Ivan's reply said it was the version of Safari involved, as opposed to the file on their end. Of course, one also does not have to create a file using the absolute newest version of (insert PDF creation program of choice). But, since I am able to view PDF files in other places using the same system configuration, I consider that the only variable changing is the hosting website for the file-- either the file or the website is requiring higher versions of Safari.

/gonna keep ranting unless I stop now. lol

BACK TO THE SUBS!
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Spenser Hamilton on October 09, 2014, 02:56:52 pm
Reading the posts to this thread indicates that there is enough passion to accomplish this.

I'm not so sure that passion is so strong outside of this community.

FWIW the Danley spec sheet isn't a web page, it's a pdf document. Blame Adobe for changing pdf too frequently.

I blame Adobe for most problems I encounter online actually :p


Sent from my iPhone using Tapatalk
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 09, 2014, 03:13:58 pm


This discussion has been enlightening to me in that specifications can be manipulated easily if there is a desire to do so.  I remember in the 70's there was controversy on power ratings on amplifiers until there was some agreement (I don't know if it was mandated) on using the RMS system.
It was actually the government (FTC) that mandated a more conservative amplifier power measurements back in the '70s including a 1/3 power pre-conditioning warm up that is all but archaic wrt modern amp designs.

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 04:10:18 pm
It has already been done.

Common Loudspeaker Format: a.k.a. CLF
All the information you ever wanted to know about a loudspeaker in one easy to understand and comprehensive format.
You can learn more about it at their website: http://clfgroup.org/ (http://clfgroup.org/)

However, you need to make it a requirement from your loudspeaker manufacturer.

Also newly available is Common Amplifier Format: a.k.a. CAF
Learn more about this at their website: http://cafgroup.org/ (http://cafgroup.org/)
Demand that your amplifier manufacturers provide CAF documentation with their amplifiers.
2 problems there.  There are not many manufacturers (of pro gear) that have CLF data.

The next is that the manufacturers are free to put whatever numbers they want into it.

Yes the "format" is common-but the numbers can be anything.  I know of cases that the numbers are "stretched" quite a bit.

What needs (I doubt it ever will) to happen is strict regulations on how things are measured.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 09, 2014, 04:44:53 pm
2 problems there.  There are not many manufacturers (of pro gear) that have CLF data.
I applaud them stepping up and developing a format.
Quote
The next is that the manufacturers are free to put whatever numbers they want into it.
True, but now it will be more obvious of some cheap POS claims spectacular numbers.
Quote
Yes the "format" is common-but the numbers can be anything.  I know of cases that the numbers are "stretched" quite a bit.
As I've said before why not name names of these "liars". If it's an honest mistake you have done them a service and they can clean up their numbers. If dishonest you helped the community by pointing them out (I appreciate this is easier to say than do). 
Quote
What needs (I doubt it ever will) to happen is strict regulations on how things are measured.
Please expand on that last one. I suspect they (CLP)  would be receptive to specific constructive advice about test procedures.

JR
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 05:07:22 pm
As I've said before why not name names of these "liars". If it's an honest mistake you have done them a service and they can clean up their numbers. If dishonest you helped the community by pointing them out (I appreciate this is easier to say than do).  Please expand on that last one. I suspect they (CLP)  would be receptive to specific constructive advice about test procedures.

JR
I cannot comment on this forum about other peoples specs-against forum rules.  So somebody else will have to comment.

And a lot of people would refuse to read and understand-because they "believe" the product-even if it can't possibly do what it says. 

A little bit of simple math goes a long ways--------------

Besides-it would have to be a number of posts------------
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Josh Millward on October 09, 2014, 05:59:03 pm
2 problems there.  There are not many manufacturers (of pro gear) that have CLF data.

The next is that the manufacturers are free to put whatever numbers they want into it.

Yes the "format" is common-but the numbers can be anything.  I know of cases that the numbers are "stretched" quite a bit.

What needs (I doubt it ever will) to happen is strict regulations on how things are measured.
The point is that it has been done already.

The consumers of this gear need to demand this information from the manufacturers. Once they do, it will come.

Also, the consumers should demand that this information be from an independent third party, not the manufacturer's own in house "engi-marketing" department.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tom Roche on October 09, 2014, 06:09:51 pm
2 problems there.  There are not many manufacturers (of pro gear) that have CLF data.

The next is that the manufacturers are free to put whatever numbers they want into it.

Yes the "format" is common-but the numbers can be anything.  I know of cases that the numbers are "stretched" quite a bit.

What needs (I doubt it ever will) to happen is strict regulations on how things are measured.

Perhaps there's an opportunity to start a non-profit org much like Underwriters Laboratories to objectively test manufacturers' speakers (and amps) and provide the results.  Establish standards, be consistent, generate an accurate "apples-to-apples" comparison.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 06:45:17 pm
The point is that it has been done already.

The consumers of this gear need to demand this information from the manufacturers. Once they do, it will come.

But the consumers right now don't "demand" even the most basic of specs-such as a freq response graph-and they are quite happy with that.

I doubt they would "demand" a third party measure products.

And most manufacturers will resist others measuring their products-because they know what would "show up".

I support the idea however.

Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 06:47:58 pm
Perhaps there's an opportunity to start a non-profit org much like Underwriters Laboratories to objectively test manufacturers' speakers (and amps) and provide the results.  Establish standards, be consistent, generate an accurate "apples-to-apples" comparison.
Would this be law-before the product could be sold? Or simply voluntary?

I highly doubt many manfacturers would send product to the tested and the results shown to everybody-unless it REQUIRED.

The "general public" doesn't seem to care-they just believe anything somebody tells them-without even thinking if it makes sense ;)
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 09, 2014, 08:56:01 pm
Perhaps there's an opportunity to start a non-profit org much like Underwriters Laboratories to objectively test manufacturers' speakers (and amps) and provide the results.  Establish standards, be consistent, generate an accurate "apples-to-apples" comparison.

There already are for profit test labs and if the consumers demanded/rewarded it they would be more widely used. As mentioned the government and FTC got involved back in the '70s when they judged consumers too ignorant to sort through the ridiculous power claims (fools and their money). In my judgement the 1/3 power pre-conditioning test standard increased transformers and heat sink size in many low cost products that the consumers didn't want or need.  There are often subjective judgements involved in establishing objective standards.   

For example in the CLF power amp spec they describe a burst test with a specific duty cycle (20 mSec on-480 mSec off). I actually kind of like that burst test. It mimics an old IHF test IIRC, and I've used it before, but that duty cycle will not be exactly representative of every musical genre.. That said if all amps are tested to the same duty cycle standard they can be compared. While I suspect these results will be as mis-applied as existing test standards.

JR
 
Note: I designed an amp capable of several dB of burst power back in the '80s and the 20mSec on/480mSec off duty cycle reduced my peak power from close to 150W for a single cycle burst to 100W clean for the full 20mSec burst (twice a second). FWIW I called that amp 100W peak because that's how I roll.  8)
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tom Roche on October 09, 2014, 09:09:00 pm
There already are for profit test labs...

It may need to be a non-profit, much like UL, to mitigate undue influence.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 09:09:09 pm

 
Note: I designed an amp capable of several dB of burst power back in the '80s and the 20mSec on/480mSec off duty cycle reduced my peak power from close to 150W for a single cycle burst to 100W clean for the full 20mSec burst (twice a second). FWIW I called that amp 100W peak because that's how I roll.  8)
The difference is between what looks good on a spec sheet or marketing brochure and what is usable.

I am like you, and would much rather take the conservative approach and make sure that others can duplicate the results-rather than present unusable "fancy" numbers.

But those are harder to sell-since many people do not want reality-they want some "fantasy" numbers that impress them and they can talk about-------------
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 09, 2014, 09:13:06 pm
It may need to be a non-profit, much like UL, to mitigate undue influence.
So how many people in our business would buy a speaker because it had a specific "tag" vs something that is cheaper and give large false numbers?

I would argue that price is the major driving force.  Except for installs where certain "tags" are expected.

This would a long slow process and the major players would have to "get on board" with it for the average person to take notice.

But what is in it for them?  Especially if the numbers they "want" don't show up on the tests?  Why lose sales over something that the average person doesn't care about?
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Roberts {JR} on October 09, 2014, 10:44:42 pm
It may need to be a non-profit, much like UL, to mitigate undue influence.

You have a pretty low opinion of professional test engineers. It's not like they are politicians.  8)

I can not imagine an independent test lab that could be bought off, and risk losing the business from every other customer...

IMO most bad specs are due to ignorance or misunderstandings not active cognizant malfeasance, while It probably does happen.

JR

 
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Tom Roche on October 09, 2014, 11:21:16 pm
You have a pretty low opinion of professional test engineers. It's not like they are politicians.  8)

I can not imagine an independent test lab that could be bought off, and risk losing the business from every other customer...

IMO most bad specs are due to ignorance or misunderstandings not active cognizant malfeasance, while It probably does happen.

JR

My opinion of test engineers is not the issue.  Ivan routinely laments the fact that various audio companies massage the specs to make their products appear better.  If true, then it might be considered a form of deception.  If he or anyone wants objectivity, then an independent lab must operate in a way that minimizes or eliminates any potential undue influence.  Otherwise, they'll end up being another Julian Hirsch at Stereo Review, essentially giving decent reviews to the hands that feed you.

Look, I don't give a rats tushy if anything happens that leads to some standard for speaker and/or amp specs.  Ultimately—for me anyway—it's the sound that matters, followed by reliability, support and cost.
Title: Re: Which subs to buy? Paralysis by analysis
Post by: Ivan Beaver on October 10, 2014, 09:29:49 am
My opinion of test engineers is not the issue.  Ivan routinely laments the fact that various audio companies massage the specs to make their products appear better.  If true, then it might be considered a form of deception.  If he or anyone wants objectivity, then an independent lab must operate in a way that minimizes or eliminates any potential undue influence.  Otherwise, they'll end up being another Julian Hirsch at Stereo Review, essentially giving decent reviews to the hands that feed you.

Look, I don't give a rats tushy if anything happens that leads to some standard for speaker and/or amp specs.  Ultimately—for me anyway—it's the sound that matters, followed by reliability, support and cost.
The question is-what are specs good for?  Yes it is the sound that matters=but sound quality does not show up on the spec sheet.

But what the spec sheet DOES DO (or at least SHOULD DO) is to give an idea of the suitability of a product for a particular job.

It does not matter how good it sounds-if it does not get loud enough or cover the intended audience area.

The specs SHOULD give a realistic idea of how loud the product can get-covering a specific freq range and a particular area.

Once you have narrowed down the list of candidates to products that can do the job-THEN you start to listen for sound quality.

In my opinion starting with sound quality is the wrong way to choose a product.

Most headphones sound pretty good-but they are limited in how many people that can hear them-so that kinda rules them out for an audience of any size-ALTHOUGH they sound good---------

First things first.

So how is this "lab" going to be funded?  I would LOVE to have a standardized labs that ALL products would be measured in the same way/conditions etc.

But our industry is simply to small for that to happen-I think.  But it IS a good idea.

But then again the buying public has to actually CARE and understand the results-which sadly most of them simply do not. 

It is more about bragging rights than any actual performance :(
Title: Re: Which subs to buy? Paralysis by analysis
Post by: John Rutirasiri on October 28, 2014, 11:07:57 pm
I have a handful of TH118's and JTR Orbit Shifters in inventory.  Use them for outdoor festivals and indoor corporate gigs.  You can't go wrong with either one -- two of the best high output portable (one-man handling) subs available.  Absolutely trouble-free.  Super tight, punchy, musical.  Having come from JBL SRX728S and Grundorf GT3600, the TH118 and OS run circles around them in sheer output and sound quality.

8 of either one provides ample foundation for smaller street festivals.  Indoor, I honestly need 2 for a 20000 sq ft ballroom, possible 4 if DJ plugs in to FOH.

If you're anywhere near Chicago, stop by and I'd be glad to A/B them for you.