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CEA-2010 Subwoofer Testing Master Thread

hardisj

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#1
Foreword:
Hey, guys. You may have seen my other thread gauging interest in a "budget subwoofer shootout".

Based on the positive feedback, I ordered (5) 10-inch powered subwoofers. After conducting the tests I thought "Hey, this wasn't so bad. I could do this for other subs". And thus, the evolution of a simple shootout to what I plan and hope will turn in to a master database of subwoofer testing.

First, however, I think it is important for me to lay the groundwork for this testing and provide some insight in to my testing setup and methods. Therefore, I have created the video below as my kickoff. I think some insight in to this will help people understand just exactly what is being tested and how the results are compartmentalized for sharing with the world.





That's it. Below is the link to my google sheet where I will be keeping all of this information update. I hope you all enjoy.






Erin's Master Sheet of CEA-2010 Results:
https://docs.google.com/spreadsheets/d/18bz7z-xIlRJsC-bw6k4mHkuwv_uiGAMyEhgrTkjwdXc/edit?usp=sharing


If you have a question, read the notes. They are there for a reason and may answer your question. If you want x/y/z... I probably won't provide it. I know, that sounds rude. But I want to keep this simple. I have added and removed countless formulas, sheets, and graphs all because I thought "yea, it would be cool to have but the average person won't need it and they'll get confused". Remember, the people who are likely to pay attention to these numbers may not care about all the fun things you can do with the data. They just want the results.

I initially had A & B on the same sheet. I thought it would be easy to navigate and understand. I sent it to some friends who aren't familiar with the specs and they were confused because I had so many little "notes" because A & B don't have the same frequency set. So, I split the results out to separate sheets.

Also, read the Foreword. It explains the method, the difference between A & B and why I will or will not provide certain data.


Contribute:
If you like what you see here and want to help me keep it going, please consider donating or purchasing a shirt via my Contribute page located here. Donations help me pay for new items to test, hardware to build test rigs (some speakers require different test stands), miscellaneous items and costs of the site's server space and bandwidth. All of which I otherwise pay out of pocket. So, if you can help chip in a few bucks, know that it's very much appreciated. Or, if you have a subwoofer you'd like to have tested, please contact me. If you can cover shipping both ways that would be great but maybe with enough donations we can take care of that or help offset the costs.




https://www.erinsaudiocorner.com/contribute/
 
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hardisj

hardisj

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Thread Starter #3
Just a little question about CEA-2010, how are port problems (chuffing, resonances, leaking) detected in the standard?
Not with an absolute guarantee. It depends on the tuning frequency. The way the CEA-2010 is set up, the test only consists of 1/3-octave tone bursts. So if the vent noise is outside of those frequencies it won't be highlighted as well as another that has vent noise at/close to one of those frequencies.

I do have a "comments" section in my spreadsheet where I plan to include things I notice during testing and that would be one of them. I'm considering adding an additional test with a nearfield measurement at the port and using a sweep to see how much output there is at the port. But converting that to a "no kidding, crazy noise" stat isn't exactly straight-forward because the level of noise will depend on the output and it's not exactly feasible to sweep 10's of output levels and, unfortunately, there is no standard voltage input because the amps gain ratio will all differ. So... yea.
 
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hardisj

hardisj

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Thread Starter #5
I posted the OP on Audioholilcs last night. James Larson brought up the matter of using 2010-A vs 2010-B for my measurements. I purposely left out mention of -A or -B in my video because it's of little consequence to how I set things up and how the measurements are performed (it only matters how they are considered in pass/fail).

For those who don't know, the main differences between the two standards are that '-B':
1) has a wider frequency set
2) adjusts the distortion threshold for a higher tolerance at lower frequencies

Personally, I like these features. Here's my two cents on exactly why:
"On one hand, I like that 'B' is weighted per frequency. Geddes' & Lee's research is heavily weighted (no pun intended) toward the masking aspect. And my own years' worth of non-linear distortion testing has proven to me that not all distortions are equal and that music as the stimulus is best to help determine these things but since that can't be used we need to do our legwork to provide multitone, IMD and HD testing (all three are tests I provide). Even still, they can't guarantee with 100% accuracy that what is in the data will translate to what one hears because of the immense amount of variables. I also like that 'B' added the higher frequencies. I know some say that's inconsequential but to me it is important as it provides an idea of linearity. If a speaker has high inductance and/or high Bl assymetry/non-linearities that will show up in the midrange. For a subwoofer where they always play at/below Fs, this is even more important because the linearity will tell us just how good the motor design is and if that motor design has features like shorting rings to lower the inductance swing. Not to mention the fact that it is easier to blend a speaker to another one when both are linear because you can more easily control the integration when you aren't fighting high delay values and don't have features like an all-pass or variable phase (another all-pass). I deal with this kind of thing all the time when tuning systems. People don't seem to grasp how incredibly, incredibly important subwoofer linearity is not just within the typical passband but also outside of it."


But, James brought up the valid point that if I test with -B, my results won't be remotely comparable to others'. Including Audiholics', Data-Bass, and Brent Butterworth's. It's worth noting that all use varying software and as outdoor tests go, the data is only as good as how the test is conducted. Nonetheless, gearing my tests toward using the -A method would help provide a more consistent comparison across all our datasets. I like that.

I can also take the -A portion and add on the additional frequencies quite easily. Making it a hybrid of A & B wrt frequencies tested. It wouldn't be strictly to spec. But it might be a good compromise.

So, I guess what I am asking here is... what do you guys think? I can pretty easily go ahead and re-test the (5) subwoofers I have on hand. However, once I am done with these and either send them back or sell them off used, that's it. And I will stick with whatever method I have chosen at that point.

If you want me to go with -A or -B let me know here. I'm leaning toward re-testing with -A. But, this is why I haven't released any data yet. I'm just laying the ground work. I don't want to start producing data for consumption until everything is finalized. :)

- Erin
 
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hardisj

hardisj

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Thread Starter #7
I mean, Audioholics hasn’t tested too many subs and Data-Bass has done any recently to my knowledge, and most of those are DIY anyway. I’d say stick with B.
Well, that's true.

But, it won't take me a terribly long time to re-test. But if I am going to do it, I need to do it soon. Because once I settle on a method, that's it. I won't be going back and re-testing anything after this set.
 
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hardisj

hardisj

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Thread Starter #9
The concern James brought up is that the distortion thresholds for the lower frequencies are far too high. I can't honestly say I agree with his assessment or not; I wasn't listening for that while conducting the tests as I was more concerned with watching the data samples being captured to make sure they were noise-free and of merit.
 

MZKM

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#11
The concern James brought up is that the distortion thresholds for the lower frequencies are far too high. I can't honestly say I agree with his assessment or not; I wasn't listening for that while conducting the tests as I was more concerned with watching the data samples being captured to make sure they were noise-free and of merit.
Should be able to test yourself, get a subwoofer that’s decently clean, play a 40Hz note and an 80Hz note, reduce the 80Hz note till you can no longer hear it, then do it in reverse. Try again with a 40Hz note and 120Hz note.

Also, for max SPL with distortion thresholds, are you using Line-In or LFE? Allowing it to play without any crossover limiting the top end will let in more harmonics, and I’d say 90% or more will be using a crossover, so the distortion they encounter will be lower.
 
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hardisj

hardisj

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Thread Starter #13
Should be able to test yourself, get a subwoofer that’s decently clean, play a 40Hz note and an 80Hz note, reduce the 80Hz note till you can no longer hear it, then do it in reverse. Try again with a 40Hz note and 120Hz note.

Also, for max SPL with distortion thresholds, are you using Line-In or LFE? Allowing it to play without any crossover limiting the top end will let in more harmonics, and I’d say 90% or more will be using a crossover, so the distortion they encounter will be lower.
The problem is that I do not have $92 laying around just to compare the limits of both.
I can tell you what they are. But the point, to me at least, isn't so much about whether or not I can hear it (because, we all know audible distortion of a tone burst vs a tone vs music is going to vary between persons). I'm more concerned with doing it the right way. It seems these guys shun the -B standard. But, I know how testers can be. Sometimes they are blinded by their own opinion (myself included).

I have emailed Klippel to ask their opinion. I am hoping they can provide insight as to what the industry (not hobbyists) use.
 
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hardisj

hardisj

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Thread Starter #14
The problem is that I do not have $92 laying around just to compare the limits of both.
Here is the -A spec:
All frequencies have the same thresholds:
Fundamental = 0
2nd order = -10
3rd order = -20
4th order = -25
5th order = -35
6th order = -45

And looks like this (from Audioholics):




-B is varied by frequency and typing those up is a royal pain, so let me quote another user:

Here are the harmonic distortion limits from ANSI/CTA-2010-B. The test signals are 1/3 octave band-limited tone bursts from 20-160 Hz. Band 1 is 20-32 Hz, band 2 is 40-63 Hz and band 3 is 80-160 Hz. The center frequencies of the 1/3 octave bands are 20, 25, 32, 40, 50, 63, 80, 100, 125, and 160 Hz.

It is worth noting that -B doesn't call out values for <20Hz. Which makes me wonder... does -A? Or have the reviewers been simply applying the thresholds to the lower frequencies at will (and for that matter, to higher frequencies since -A only goes up to 80Hz, IIRC)? If the latter, IMHO, that's where the line between "Specification" and "I'm gonna do what I think should be done" is clearly crossed. But that's a different matter...
 
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hardisj

hardisj

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Thread Starter #16
B does look saner (less forgiving of stuff in the >80 Hz zone) to me.
Agreed. That’s why I like this spec.
I am curious to see what Klippel’s response on the matter is, assuming they have enough insight as to what is used in the industry to be able to provide a recommendation.
 
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hardisj

hardisj

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Thread Starter #17
I spoke with Brent Butterworth last night. He gave me some good insight. In a nutshell, he still prefers -A but seemed to not be staunchly against -B. Personally, I like -B. But comparison against others' -A testing is nice to have as well.

Therefore, I have decided that I will provide both -A and -B spec results. It will take more time. But it will cover me for both *general* comparison against others' tests and future proof me if -B takes over and people begin adopting it more fully. And if, for some reason, I decide to quit producing one of the formats then I'll do that.

Since the spec for -A doesn't specify thresholds for anything other than 20-63Hz, I will do the same as others have done and use the same thresholds for other frequencies. But, I will make sure to note those are not within the purview of the -A standard and are thus provided as "extra" with those thresholds.

AFAIK, -B doesn't specify thresholds for <20Hz. I have contacted Klippel about their advice on this.

So, I will re-test the subwoofers I have on hand with -A this week (weather permitting) and then I will post the data for both standards' results.

- Erin
 
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EJ3

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#18
I posted the OP on Audioholilcs last night. James Larson brought up the matter of using 2010-A vs 2010-B for my measurements. I purposely left out mention of -A or -B in my video because it's of little consequence to how I set things up and how the measurements are performed (it only matters how they are considered in pass/fail).

For those who don't know, the main differences between the two standards are that '-B':
1) has a wider frequency set
2) adjusts the distortion threshold for a higher tolerance at lower frequencies

Personally, I like these features. Here's my two cents on exactly why:
"On one hand, I like that 'B' is weighted per frequency. Geddes' & Lee's research is heavily weighted (no pun intended) toward the masking aspect. And my own years' worth of non-linear distortion testing has proven to me that not all distortions are equal and that music as the stimulus is best to help determine these things but since that can't be used we need to do our legwork to provide multitone, IMD and HD testing (all three are tests I provide). Even still, they can't guarantee with 100% accuracy that what is in the data will translate to what one hears because of the immense amount of variables. I also like that 'B' added the higher frequencies. I know some say that's inconsequential but to me it is important as it provides an idea of linearity. If a speaker has high inductance and/or high Bl assymetry/non-linearities that will show up in the midrange. For a subwoofer where they always play at/below Fs, this is even more important because the linearity will tell us just how good the motor design is and if that motor design has features like shorting rings to lower the inductance swing. Not to mention the fact that it is easier to blend a speaker to another one when both are linear because you can more easily control the integration when you aren't fighting high delay values and don't have features like an all-pass or variable phase (another all-pass). I deal with this kind of thing all the time when tuning systems. People don't seem to grasp how incredibly, incredibly important subwoofer linearity is not just within the typical passband but also outside of it."


But, James brought up the valid point that if I test with -B, my results won't be remotely comparable to others'. Including Audiholics', Data-Bass, and Brent Butterworth's. It's worth noting that all use varying software and as outdoor tests go, the data is only as good as how the test is conducted. Nonetheless, gearing my tests toward using the -A method would help provide a more consistent comparison across all our datasets. I like that.

I can also take the -A portion and add on the additional frequencies quite easily. Making it a hybrid of A & B wrt frequencies tested. It wouldn't be strictly to spec. But it might be a good compromise.

So, I guess what I am asking here is... what do you guys think? I can pretty easily go ahead and re-test the (5) subwoofers I have on hand. However, once I am done with these and either send them back or sell them off used, that's it. And I will stick with whatever method I have chosen at that point.

If you want me to go with -A or -B let me know here. I'm leaning toward re-testing with -A. But, this is why I haven't released any data yet. I'm just laying the ground work. I don't want to start producing data for consumption until everything is finalized. :)

- Erin
Mine are 2 boxes from largest of the old Radio Shack sub-woofers and Pioneer 12 inch dual 4 ohm voice coils with a specified Freq. Response of 20Hz to 80Hz (each is set up to run at 2 ohms) & powered by a NAD 2200 capable of 800 watts RMS a channel into 2 ohms. The xover is a Harris analog that is set up <60 Hz->80 Hz. Just throwing this into the mix as a thing to think about along what is the best testing protocol, as I have no idea which would be the best way to test them. I am, however, greatly appreciative that you are taking this task on.
 

Juhazi

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#19
CEA is basically a stress test, to find out max spl.

I'd like to see a nearfield sweep too, moderate spl 5-5000Hz, with no lowpass and with it. Also the effect of LF boost etc. if available. It will show bass slope and internal resonances, as well as reflex/line tuning. Port signal nearfield with same range obviously too!
Also the effect of LF boost etc. "eq" if available.
 
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hardisj

hardisj

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Thread Starter #20
Yes, it's a stress test (of sorts). That's understood. But the different formats have different distortion tresholds (and frequency ranges) which result in how the max SPL is defined. It's important that this be understood.

Most of what you are asking for, I will be providing, depending on the subwoofer. :)
 

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