[Danny Richie]

I have been asked several times in the past to post a response to some of the mis-information posted on the Zaph- Audio web site, and I am finally responding to those requests. Some were actually made a long time ago.

I really have had little interest in responding to this as I have not had time to bother with it and really didn't feel like enough people were paying any attention to this insignificant site. I still don't have the time for this but enough people have noticed and I have had to respond to enough individuals lately that I feel like it might be worth the time to respond. This response was also motivated by false and misleading information posted about our drivers.

I have contacted John directly in an e-mail but got a rather hostile response ending with:

"Don't email me or call me, I'm not interested in having a "discussion" with you in much the same way I'm not interested in petting a rabid Chihuahua after I kicked it off my leg."

Below is a copy of the e-mail that I sent.

Hi John,

I see that your site is actually getting quite a bit of attention from your posting of measured data. I think you are attempting to provide a valuable service to the DIY community. Educating the public is not easy. Often though I see as much misinformation as useful information, or misinterpretation of the data by those viewing it. No offense meant, but I see you as very early in the learning curve with some of this stuff and I'd like to help you.

Would it be okay if I call you up and chatted with you for a while?

Danny Richie

Subsequent e-mails sent were blocked and did not reach him.

John,

If you are reading this now, my message to you is that I would still be willing to discuss any of these issues with you. I would be glad to share my knowledge with you, and give you assistance in proper measurement taking and understanding or interpreting the data. I will even be glad to send you drivers for testing. I am not mad or upset as you have suggested but having to respond to this and deal with your attitude is a bit aggravating. You are welcome to respond here in my forum if you like, but please spare me the snake oil salesman accusations that I have seen from you in the past.

To any others that would like to respond or add to the things that will be addressed below please feel free.

Below and in subsequent post I will attempt to deal with the following:

1) The first thing I am going to deal with is the false and misleading information about our drivers.

2) Secondly, we will have a look at distortion measurements and put them in perspective. 

3) I'll comment on what really makes an audible difference and what to really look for in a driver.

4) Lastly, if I have time I'll touch on other posted mis-information and try to re-educate.

[Danny Richie]

These measurements and information was posted quite some time ago.

http://www.zaphaudio.com/surface5test/

Here three woofers were tested "HiVi W5 vs GR M130 vs Vifa TC14"

My first issue with this are the comments made about my M-130 woofer.

"GR M130 - coated paper cone, plastic frame w/6 holes, fake phase plug, good motor venting. Breakup node at 5.5kHz with energy storage problem. Strange suckout at 1900hz, not visible in gated or smoothed curves."

First of all the frame is NOT plastic. The frame is a high strength polymer similar to what many pistols are made from. I once watch my 260 pound business partner jump up and down on one of these frames with both feet. It did not bend it or break it. These are really tough frames and have a specific advantage over other types of frames. I'll get to that shortly.

Secondly, the dust cap is NOT a fake phase plug. The shape and type of dust cap was selected for specific reasons. This dust cap was compared to several other types. It added some mass that was desired, and it gave the smoothest response than with others tested.

Thirdly there is NO breakup node at 5.5kHz or energy storage problem in that area. In fact if you look at the cumulative spectral decay of all three woofers tested you will not only see that there is no energy storage problem at 5.5kHz but it is the cleanest in that area of all that were tested.

There is also no strange suck outs at 1900Hz. This may have been an artifact of the way that they were measured (in the near field). If it is there when not gated but not there when gated then it is clearly an artifact of a cancellation from a late arriving reflection.

Then I found this comment particularly humorous.

"I'd pay 10 extra bucks to get a metal frame".

Allow me to educate on this one. All metal frames ring to some degree. All you have to do is play the woofer at the resonance frequency of the frame to excite it. Many people have realized improved sound of their speakers by damping the woofers frame with some type of damping material, lead dots, etc. The high strength polymer does not have this issue to contend with. It also will not transmit a resonance to the front baffle like many metal frame woofers will. If I had an extra ten bucks to spend, I'd get the one with the polymer frame.
 
The next issue I have had with the posted data on our drivers is the measured T/S parameters posted.

The M-130 measurements are posted at the bottom of the same page.

From the measured T/S parameters I can see that the driver has not been burned in or it was tested in a way that did not accurate reflect the real T/S parameters.

See before and after burn in parameters on an M-130 here: http://www.gr-research.com/burnin.shtm

What is perplexing is that someone would go to the trouble of measuring and posting data on a woofer (as if performing some type of service to the DIY community) and not properly burn in the woofer (a disservice). Not only will the T/S parameters be different but it can also have an effect on measured distortion figures as well. This makes those measurements fairly meaningless. Would you rather know what the T/S parameters are on a driver out of the box or after burn in? Since pre-burn in figures are temporary it makes little sense to post parameters of a fresh out of the box woofer.

Similar inaccuracies were posted regarding our M-165X woofer here: http://www.zaphaudio.com/6.5test/

Comments made are below:

Comments: This is a paper cone woofer with a well ventilated plastic frame and Adire's XBL^2 dual-gap, short coil motor design. The response curve is smooth with some mild breakup starting at 3kHz. Harmonic distortion is on the high side, and it's obvious that this motor doesn't have a copper sleeve over the pole piece like the Extremis or AA 6.5 poly. Sensitivity is relatively high, and the motor will remain linear at high output. The suspension is a bit too small to fully support the excursion the motor is capable of.

Again the frame is a high strength polymer and NOT plastic.

The is no breakup in the 3kHz region either. John is confusing an amplitude peak with breakup. The difference can clearly be seen in the spectral decay of his own measurements: http://www.zaphaudio.com/6.5test/csd.html This is actually the most useful data posted about the drivers tested.

Without properly measured 1 meter measurements on a baffle the response below 400Hz or so is not accurate and of little value. But accurate responses above that range can be accurately made with his measuring methods. The spectral decay is very telling and I will elaborate more on that when I address the value of distortion measurements.

An amplitude peak is in increase in output only. The decay rate should die out just as fast as the response any where else.The amplitude peak that he showed in his measurements are clearly below the level of the graph by less than 2 ms.

Breakup is a resonance issue and it can be identified by a long and continuing decay in the area of the resonance. See the spectral decay of just about every other woofer tested to see what a real breakup resonance looks like. 

The M-165X was one of the cleanest woofers tested and had less stored energy issues than any of the other woofers tested. A few others were also very good, but many were horrible.

Again distortion is an area that I will spend more time with in a different segment.

It is also funny that he claims that it is obvious that the motor doesn't have a Copper sleeve over the pole piece when he can't even see the pole piece and has no basis by which to make such statement. It actually does employ the use of a Copper ring.

John's measured T/S parameters of this woofer seen here: http://www.zaphaudio.com/6.5test/ts.html

This also shows that the driver was either not properly burned in before measuring or testing it or it was improperly measured. Posting data and parameters on a woofer that has NOT been burned in for at least 40 to 50 hours will give you data that is of little or no value.

[Danny Richie]

On to distortion measurements and the value or lack there of...

First of all, distortion measurements will NOT tell you how good or bad a woofer will sound.

Secondly, distortion measurements taken at a fraction of one watt and from a few inches away from a woofer will NOT give any meaningful data in ranges normally covered by a woofer and specifically the sub 1,000Hz ranges.

Straight from the Clio 7.0 manual:

Supposing we carry a distortion analysis at an average 90dBSPL, residues below 1% are difficult to evaluate up to 600Hz, things are much better at higher frequencies.

And...

While it is simple to obtain meaningful distortion figures of electrical devices, measuring Loudspeaker
distortion in normal environments (without anechoic chamber) is not easy.

One reason that it is not easy is that the average distortion levels are below any normal environmental noise present in any given listening room.

Again from the Clio 7.0 manual:

50 dBSPL of ambience noise, a common figure, usually does not affect Amplitude
evaluation which is usually carried out at an average level of 90dBSPL. This is
particularly true using CLIO Sinusoidal Analysis capability which, by means of DSP
filtering, allows exceptional S/N Ratio. Unfortunately evaluating 1% distortion means
looking for signals that are 40dB lower than the 90dBSPL mentioned above, in the
same order of magnitude as environment noise.

Now let's put this into perspective and in relation to more obvious issues.

Lets look at a couple of those metal cone woofers. Check out the breakup.





The break up area continues to play long after the original signal has ended. It is heard as a ringing. THEY RING! This can also be considered a non-linear distortion as well. It is a coloration generated by the woofer itself.

Typically a second order network might get this breakup area down by as much as 18db if it is crossed over well before that range. Obviously crossing them only one octave before the breakup will still leave you with lots of audible breakup and massive ringing at an amplitude equal to the fundamental. A third or fourth order electrical network will typically push the breakup range down about 20db or more depending on where it is crossed over. The sooner the better.

Most people feel that getting the breakup range down 20db below the fundamental is okay.

Hey guys this means if your listening level is 90db then the breakup area (RINGING) is around 70db range. If you are really lucky you might get it down to the 65db range.

Now which is the bigger problem, the ringing at the 65 to 70db range, or the measured distortion levels that are below 50db?

The only networks that I know of that will handle the metal cone woofer breakup in a way that gets it close to 50db ranges are the 120db per octave networks (elliptical or infinite networks) used by Joseph Audio.

Now lets put some perspective on the measured distortion taking itself.

As mentioned earlier a figure derived from a fraction of a watt a couple of inches from the cone is meaningless.

If you want to see real world figures then take them at real world levels. Things change with real input levels.

Take a typical woofer with underhung or overhung voice coils. Push the woofer to levels near X-max and guess what happens? As the woofer is forced into long exertions the voice coil gets further out of the gap. Its field strength drops. As less and less voice coil is left in the gap the woofer looses its control. Bl figures drop, and guess what? Distortion goes up.

Now take a woofer like the Extremis or the M-165X. They use a multiple gaped design (XBL^) that keeps a linear BL and keeps the same amount of voice coil in the gap over a wide range of travel. Guess what the result is? Distortion is keep low as there is no BL drop or non-linear field strength on the coil.

Of coarse you won't see this with a fraction of a watt of power.

Perspective goes a long way. Let's try not to loose it.

More later when I have time...

[Kevin Haskins]

"Don't email me or call me, I'm not interested in having a "discussion" with you in much the same way I'm not interested in petting a rabid Chihuahua after I kicked it off my leg."

I'd say he doesn't like you Danny.      Unless a rabid Chihauhua is some kind of secret code word.   

[sts9fan]

whats the difference between polymer and plastic?  Nothing.  All plastics are polymers. Semantics

I don't think you should get your panties in a bunch over a DIYer

[Danny Richie]

I'd say he doesn't like you Danny.

Well he's one of those Peter Aczel supports and I am one of those guys that listens and hears differences and stuff (I'm the enemy).

I don't think you should get your panties in a bunch over a DIYer

True, but I'm not really all freaked out over it or anything, just tired of responding to individuals over it. Now I can just direct people here instead.

[Vapor Audio]

I hardly think Danny's getting his "panties in a bunch".  He's correcting mis-information, and I'm glad he is.  There are a LOT of people out there who make design decisions 100% based on Zaph's data, and other sites with incorrectly taken measurements.  I'd much rather Danny take the time to post all this info and give us more perspectives to work with than do nothing.  

[Daygloworange]

Unfortunately, due to the internet, if Danny posts nothing to the contrary, then Zaph's findings become the Gospel.

Good move.

Plus, we all learn a little more, which is a good thing. Unless of course...

Cheers

[srb]

John is, by his own definition, a hobbyist/blogger.

Danny is an audio professional with many well-reviewed speaker designs for his own GR Research as well as designs for other established audio companies.

'nuff said.

Steve

[Daygloworange]

John is, by his own definition, a hobbyist/blogger.

Then, he shouldn't be posting and commenting as if he was doing a credible, comprehensive and valid reference.

The site name is Zaph Audio. What does that imply to people?

Cheers

[konut]

Danny, great job in explaining the details of your products. You may want to reconsider not responding immediately to such mis-information about your products in the future. Due to the internet, the dissemination of erroneous information seems to exceed the speed of light. By not responding immediately, as DGO so rightly pointed out, you lend cred to someone who doesn't deserve it. Today's detailed explaination, I think, would have saved you considerable time, and frustration, had it been posted earlier.

[Daygloworange]

Anybody who responds with:

"Don't email me or call me, I'm not interested in having a "discussion" with you in much the same way I'm not interested in petting a rabid Chihuahua after I kicked it off my leg."

has got some serious issues. Sounds like he's got a burr in his saddle about anyone who would question his findings or methods. Most credible people like sharing thoughts and findings with peers.

Sounds like he's more concerned with preserving his ego, than actually learning something...

Danny doesn't have this recessive gene. 

Cheers

[geekinthehood]

Danny -

I've been following news of your speaker designs for the last few years. Initially, I was interested in speakers by Newform Research. Then I heard about a line array developed by someone using Newform's ribbon. After doing a search on "newform" and "line array", I learned about your Alphas. I also learned who I trusted and who I'd rather do business with. A few months ago I found out that AV123 was selling your LS-6/9, so I paid for a pair of piano rosewood LS-9s. (brief pause while I celebrate...)


I've been silent on the forums until now because I'm here to learn and don't really have much to say. I'm only chiming in now because I wanted you to know that your ethics, manners, accessibility, knowledge, and willingness to share that knowledge make a difference. (did I cover everything?  )

Okay, I guess that sounded kind of mushy, but I stand by it. Keep up the good work - people notice.

[Watson]

John Krutke won't have the time or interest to respond to your posts, but your "debunking" is not very accurate.  In several places it is unfair or wrong.

It's not as if John Krutke has any beef with your drivers when used appropriately; he even has a project posted that uses the M130 (the only project from someone else he liked enough to post).

From the measured T/S parameters I can see that the driver has not been burned in or it was tested in a way that did not accurate reflect the real T/S parameters.

See before and after burn in parameters on an M-130 here: http://www.gr-research.com/burnin.shtm

What is perplexing is that someone would go to the trouble of measuring and posting data on a woofer (as if performing some type of service to the DIY community) and not properly burn in the woofer (a disservice).

What you're saying is simply not true.  John Krutke (Zaph Audio) burns in midrange drivers for 10 hours before measuring TS params.  That's sufficient for the TS params to stabilize.

I don't understand why you're alleging John's measurements are wrong.  The pair of GR M130s I bought for my MBOW1s had measured TS params that were very different from the ones you've posted after running them in for two evenings as burn-in.  I attributed this to manufacturing variation (these are inexpensive woofers after all), not some scheme on your part to misrepresent your drivers -- frankly, I think it's bizarre and somewhat unfair to criticize John on the basis that his measured TS params are different, given that there is such an amount of manufacturing variation.

Mark K has also posted independent measurements of the GR M130 using a different measurement rig and different software, and they're basically the same as John Krutke's measurements.

Again the frame is a high strength polymer and NOT plastic.

???  Virtually all plastics are polymers.

As for your remark about the frame not bending when your business partner jumped on it, that's just silly and not realistic.  The plastic frame on my M130s bended a little as I was screwing it in due to the gasket pushing back.  There's no way a person could jump on it and not have it bend.  I understand you're proud of your product, but a certain degree of realism is appropriate too.

The is no breakup in the 3kHz region either. John is confusing an amplitude peak with breakup.

This is semantics.  A hump along the depth axis on a CSD plot is caused by resonance; the only difference between "breakup" and "ringing" as you define those terms is the time for the resonance to decay.  The threshold you choose to use is arbitrary; you used the example of approximately 2 ms.  John is not making any distinction, because they're both resonance-based artifacts.  To claim he misunderstands the issue because you're using terms in a different way than he is misleading.  His comments are accurate.  Also, he uses the term "mild" to describe the breakup precisely because it decays quickly

The break up area continues to play long after the original signal has ended. It is heard as a ringing. THEY RING! This can also be considered a non-linear distortion as well.

This is where you're just flat out wrong.  Anything shown on a CSD plot is linear distortion by definition (it's a linear system, no new frequency components are added to the output that didn't exist in the input).  This point -- the distinction between linear and nonlinear distortion -- is very basic signal engineering.

[Watson]

Typically a second order network might get this breakup area down by as much as 18db if it is crossed over well before that range. Obviously crossing them only one octave before the breakup will still leave you with lots of audible breakup and massive ringing at an amplitude equal to the fundamental. A third or fourth order electrical network will typically push the breakup range down about 20db or more depending on where it is crossed over. The sooner the better.

Most people feel that getting the breakup range down 20db below the fundamental is okay.

You're setting up a straw man here and then knocking it down.  John Krutke agrees with you on this point!  That's why all of his metal cone designs include high Q, deep notch filters on top of the basic crossover in order to push the resonance much farther down.

I happen to agree with you Danny that even heavily filtered metal midranges have an audible signature, but so do more heavily damped cones like the M130 and 165.  The engineering decision (tradeoff) one has to make is less linear distortion or less nonlinear distortion.  That's a judgment call by the designer. 

The reality is that the M165X has higher nonlinear distortion than various other tested drivers.  That's all John's measurements point out, and it's hardly meaningless.  The nonlinear distortion profile of a driver has a significant impact on the sound of the final system.

[Watson]

Anybody who responds with:

"Don't email me or call me, I'm not interested in having a "discussion" with you in much the same way I'm not interested in petting a rabid Chihuahua after I kicked it off my leg."

has got some serious issues. Sounds like he's got a burr in his saddle about anyone who would question his findings or methods. Most credible people like sharing thoughts and findings with peers.

Sounds like he's more concerned with preserving his ego, than actually learning something...

John Krutke is just a busy guy, with a full-time engineering day job who devotes an enormous amount of his spare time to sharing information about audio.  He doesn't have a "burr in his saddle", he just sees debating people with commercial interests as a waste of time, based on past experience.  It's frustrating to argue the science of loudspeaker design with people who confuse linear and nonlinear distortion, for example.  I just spent 45 minutes typing the replies in my above posts, and honestly, it probably wasn't time well-spent, because in this type of forum, whatever Danny says will be taken as gospel regardless of its correctness.  John could of course be more charitable and less apparently abrasive, but Danny only excerpted the last sentence of that email which leaves out the context, and John has quite an aggressive sense of humor.  John has in the past said some very kind things about Danny on his blog, but he isn't one to pull punches either with respect to objective criteria, like how a driver measures.  Note that John generally places more emphasis on nonlinear distortion than linear distortion, similar to Geddes' view.

[Daygloworange]

John Krutke is just a busy guy, with a full-time engineering day job who devotes an enormous amount of his spare time to sharing information about audio.  He doesn't have a "burr in his saddle", he just sees debating people with commercial interests as a waste of time, based on past experience.

We are all busy people. Danny is busy people. Despite this he will pick up the phone and answer questions, and offer to help people in just about anyway he can. He doesn't answer polite requests with the animosity the John Krutke does. I stand by my comments on Zaph's "attitude".

John could of course be more charitable and less apparently abrasive, but Danny only excerpted the last sentence of that email which leaves out the context, and John has quite an aggressive sense of humor.

More charitable? You mean be kind enough to give Danny the courtesy of at least an opportunity to offer his thoughts and ask questions on John's methods? If that's what you mean, then, yes, he could certainly be more charitable.

Aggresive sense of humour? Uh, y'know, I'm a crack up kinda guy, but I don't see his comments as a sense of humour, but as an insecurity issue. (and a serious one)

whatever Danny says will be taken as gospel regardless of its correctness.

It's an open forum, you are posting your opinions, and Danny is posting his. Kinda cool, huh? Where is the parallel with John Krutke????

Cheers

[Danny Richie]

John Krutke (Zaph Audio) burns in midrange drivers for 10 hours before measuring TS params.  That's sufficient for the TS params to stabilize.

Drivers do take longer to burn in than 10 hours. Average time to reach stabilization is 40 to 50 hours. The T/S parameters he posted on my drivers do not reflect that of drivers having even been burned in for 10 hours. They are still way off.

See the T/S parameters during burn in of an M-130 woofer: http://www.gr-research.com/burnin.shtm

I checked a pretty good handful of these when I started this little burn in facts page and they were all VERY close to one another.

I don't understand why you're alleging John's measurements are wrong.  The pair of GR M130s I bought for my MBOW1s had measured TS params that were very different from the ones you've posted after running them in for two evenings as burn-in.

I have not seen measured parameters that far off and I randomly check samples often. His measured parameters are also off on the M-165X and in the same way. This makes me wonder about how he is measuring them.

I will be glad to send a couple of drivers that have been fully burned in and measured if he would like to check his measurement systems accuracy?

I think it's bizarre and somewhat unfair to criticize John on the basis that his measured TS params are different, given that there is such an amount of manufacturing variation.

I don't ever see them off that far. To point out that those measured parameters are not within any normal margins is not meant to criticize John. As good as his intentions may be his measurement system may still be off.

(these are inexpensive woofers after all)

Yes, but I have found the QC and consistency to be of the highest level regardless of price.

As for your remark about the frame not bending when your business partner jumped on it, that's just silly and not realistic.  The plastic frame on my M130s bended a little as I was screwing it in due to the gasket pushing back.  There's no way a person could jump on it and not have it bend.  I understand you're proud of your product, but a certain degree of realism is appropriate too.

Oh it flexed when he jumped on it. It flexed plenty, but when he was through jumping on it, it was not bent.

This is semantics.  A hump along the depth axis on a CSD plot is caused by resonance; the only difference between "breakup" and "ringing" as you define those terms is the time for the resonance to decay.  The threshold you choose to use is arbitrary; you used the example of approximately 2 ms.  John is not making any distinction, because they're both resonance-based artifacts.  To claim he misunderstands the issue because you're using terms in a different way than he is misleading.  His comments are accurate.  Also, he uses the term "mild" to describe the breakup precisely because it decays quickly

Nope, his comments are not accurate. A breakup is clearly seen as a resonance in the spectral decay. There can be a "hump" that is simply a change in amplitude and NOT be stored energy.

Anything shown on a CSD plot is linear distortion by definition (it's a linear system, no new frequency components are added to the output that didn't exist in the input).  This point -- the distinction between linear and nonlinear distortion -- is very basic signal engineering.

  Yes, but in turn if it were linear it would be the same at all frequencies.

John Krutke won't have the time or interest to respond to your posts

Maybe that's why he responded to me the way he did huh? He's got time for driver testing, but no time to learn anything from an industry professional.

The reality is that the M165X has higher nonlinear distortion than various other tested drivers.

Says who? A hobbyist that fails to burn in a driver properly before testing it? His measured T/S parameters are off.  What faith can I give his distortion measurements?

That's all John's measurements point out, and it's hardly meaningless.  The nonlinear distortion profile of a driver has a significant impact on the sound of the final system.

Nonsense. Distortion measurements taken that way in frequency ranges below 1000Hz won't tell you anything, and wether the distortion levels were .5% or .75% or 1% (measured in that way), you won't be able to tell the difference in the final sound of the system. Distortion measurements taken that way WILL NOT tell you how it will sound.

Even the computer running in the same room that he is measuring in will have a higher noise floor level than the distortion levels that he is trying to measure. How accurate can that be? Even the measurement manual states that.

or who use terms like "ringing" in a non-scientific sense.

Awe man, did I just describe the sound of a decay resonance in a non-scientific term like ringing? Oh my, I am so unscientific.

But now here is a real piece of science. "Woofers with lower X-Max sound better"

http://www.zaphaudio.com/lowxmax.html

  You're grasping if you are picking at my use of the word "ringing" to describe a resonance.

but Danny only excerpted the last sentence of that email which leaves out the context,

The rest was no different in attitude. I won't post the whole e-mail because it would look like I am trying to make him look bad. That is not my intention. I just wanted to show his attitude in response to my e-mail and his last line summed it all up just fine. He is clearly not interested in my help.

John has in the past said some very kind things about Danny on his blog, but he isn't one to pull punches either with respect to objective criteria, like how a driver measures.

I have no issues with objective measurements if taken correctly.

What I don't like seeing is un-factual observations like "Breakup node at 5.5kHz with energy storage problem" when there is none even by his own measurements.

How about calling a shaped dust cap a "fake phase plug"?

Come on man.

[dlr]

Sorry, Danny, but I've got to call you on a few comments. Accuracy counts. Taking an attitude using erroneous claims should be corrected.

Nope, his comments are not accurate. A breakup is clearly seen as a resonance in the spectral decay. There can be a "hump" that is simply a change in amplitude and NOT be stored energy.

So to what do you ascribe this hump? Something causes it. Any driver SPL FR output that is non-linear is either some form of damping that is not flat with frequency, is a resonance or is due to horn loading since the input for measurement has to assume flat FR in the input signal. Drivers are subject to the principle of conservation of energy as much as anything else. Humps would  preclude horn loading if it's in the middle of the passband.

Anything shown on a CSD plot is linear distortion by definition (it's a linear system, no new frequency components are added to the output that didn't exist in the input).  This point -- the distinction between linear and nonlinear distortion -- is very basic signal engineering.

Yes, but in turn if it were linear it would be the same at all frequencies.

Danny, taking an attitude here is inappropriate, especially since he is right and you are wrong. A linear system has nothing to do with being flat in FR. His point about it being basic is also correct. Just as you think that John could stand to learn a bit about measurements, I think that it would behoove you to be a bit more circumspect in  your pronouncements.

The reality is that the M165X has higher nonlinear distortion than various other tested drivers.

Says who? A hobbyist that fails to burn in a driver properly before testing it? His measured T/S parameters are off.  What faith can I give his distortion measurements?

Breakin is not going to have a significant impact on distortion measurements. That's a straw-man argument that does not discount in any way John's measurements. Take issue with other aspects, but to deride based on this provides no support for your position.

That's all John's measurements point out, and it's hardly meaningless.  The nonlinear distortion profile of a driver has a significant impact on the sound of the final system.

Nonsense. Distortion measurements taken that way in frequency ranges below 1000Hz won't tell you anything, and wether the distortion levels were .5% or .75% or 1% (measured in that way), you won't be able to tell the difference in the final sound of the system. Distortion measurements taken that way WILL NOT tell you how it will sound.

He didn't say that, why be so emphatic about what he DIDN"T say? He did say, accurately, that the distortion has an impact, not that it tells you how it will sound. You apparently agree by designing in a Faraday ring or should we assume that it's for advertising points without audible merit?

Even the computer running in the same room that he is measuring in will have a higher noise floor level than the distortion levels that he is trying to measure. How accurate can that be? Even the measurement manual states that.

If the measurements being made quasi-anechoic at some distance such as 1m then yes, that will have an impact. However, what's important is the relative impact. If the mic is placed close to the driver, then the relative levels are what matter. Background noise can be masked to some degree by the measurement technique used to improve the S/N ratio/. At mid and higher frequencies as well, the background noise will be non-correlated which is a significant factor. Don't be too eager to dismiss.

or who use terms like "ringing" in a non-scientific sense.

Awe man, did I just describe the sound of a decay resonance in a non-scientific term like ringing? Oh my, I am so unscientific.

Being condescending is not flattering. He is attempting to be accurate in a scientific sense. You want to have others "learn from a professional" so-to-speak, yet you would deride the scientific approach?

But now here is a real piece of science. "Woofers with lower X-Max sound better"

OK, I can't agree with that in any technical sense. But he's entitled to his position. I won't debate him on that.

I have no issues with objective measurements if taken correctly.

This is, again, presumptuous. I do see his measurements as being objective. There is not a consensus on there being one and only one method for measuring distortion. His and Mark K's are also more in the line of showing relative differences between drivers. That is valid when all drivers are measured in the same manner. John and Mark will both point out, correctly, that comparing one of Mark's to one of John's is not optimal. However, each one of them will show trends and relative differences that do have merit.

What I don't like seeing is un-factual observations like "Breakup node at 5.5kHz with energy storage problem" when there is none even by his own measurements.

Hold it. There IS a resonance at 5.5K with a relatively high Q in his measurement. I'd have to do my own measurements to identify the source, it may not be a specific breakup mode, but it is an indication of a resonance that is made more evident in the CSD. How can you say it isn't present?

BTW, do you have a set of truly anechoic or even quasi-anechoic measurements to provide? That would be enlightening for sake of comparison. Just as our measurements differ from those of, say, Scan-Speak or Seas, having yours as a basis for comparison would be interesting.

How about calling a shaped dust cap a "fake phase plug"?

That was a bit overboard. If it's not metal it won't help the distortion characteristics as a metal plug will, but it should function in the other respects, no trapped air as under a dust cap with a bit of top end smoothing.

Come on man.

I could say the same. His responses to you were accurate.

[WOR Radio]

Danny, when you have time and experience invested and are doing something "great" and providing excellent products at a very competative price point, you will have naysayers, BS artists and outright liars "out to discredit and attempt to disinfranchise" the good work and the prosperous results.

Thank you for bringing this forward. My long list of the "web haters" constantly grows longer. Eventually they will all expose themselves.

I give people credit for being able to see when a "ganging up" is happening to try to discredit good people and good peoples great works. No shortage of people making up falsehoods to attempt to sway public opinion. (to various degrees). When and if the 'web haters' begin taking your quotations and modifying them to suit your own needs, fill me in on the best course of action as this is something that has been happening with yours truly now for the last 8 or so years. Sometimes bad publicity is another form of advertising and when the record is "set straight" and the truth comes out, it can only HELP your business and your credibility. This is the way it will backfire on their head. Setting things straight here is very noteworthy and I appauld your candor and willingness to do so and not ignore it. Truth be told, seeing the BS rear its ugly head is another form of flattery. They just don't have what you have and are incapable of being able to deal with the truth without making something false out of it.

Heres to another hats off to your fine work Dan.

PM me if you like.