[Mark K]

The same goes for any data gleaned nearfield or outside of an anechoic room, and that means pretty much all of it on the internet. 

Huh,

That means everything that Danny designs is suspect too. Do you think he has an anechoic chamber?

All measurements have limitations. All measurements are approximations of the truth.

Still, it's clear from the bulk of this thread that you guys don't really understand the nature of the measurements, how they are interpreted, what is accurate and what is not. Dan's comments, while not incorrect, are quite cursory.

It is of note that the distortion measurements that John and I do are not done nearfield. a balance is struck between issues with reflections and resolution loss and nearfield artifact.

At this point, there is not much to be elucidated from this exchage. I will withdraw to my lab and library. Expect a reanalysis of the M130, a further comparison, and a more detailed, and, hopefully witty reparte on the rather superficial and often incorrect analysis you have provided. Still I have a full time job, a wife and kids, as well as a rather large laminate and travertine floor to finish, so it will take 2-4 weeks. The thread will probably be dead; I won't forget however.

(having said all that, I actually think the M130 is a pretty good driver overall. The general thought process and explanations on this thread that have critiqued Zaph has been poor however.)

TTFN

[Vapor Audio]

That means everything that Danny designs is suspect too. Do you think he has an anechoic chamber?

All measurements have limitations. All measurements are approximations of the truth.

Exactly!  That's exactly what it means.  If Danny or anybody else creates designs based soley on measurements of the component drivers, then the design is likely going to be flawed.  That's why every good design must be voiced out extensively.  And before this internet measurement craze, all designed were voiced first ... now it's gotten somewhat reversed.  Chances are all these measurements have resulted in more newbie DIY'ers (myself included) creating good first try designs.  But unless you are really skilled in the voicing, you'll never have a great design.  And I think a major problem with all these measurements being so available is that most rely on them totally in their designs, and draw incorrect conclusions about how drivers really sound. 

Still, having all these measurements available is better than not having them.  But all of us are somewhere along the learning curve of applying them correctly.  Part of the job in supplying them is educating others in using them, and also the supplier educating themselves about how to give that guidance. 

John knows a lot as do you Mark, but neither of you know everything about the subject.  John drew some incorrect conclusions about the M130 and who knows what else, and you posted some incorrect (or maybe more accurately incomplete) data about the M130.  That's not a sin, and certainly nothing to fight about.  Posting data with disclaimers is one thing, but posting conclusions when you're not 110% is dangerous business.  And I dare say that's the whole point of all this, that anyone who posts that information be careful and open to the possibility of being wrong from time to time. 

[JohninCR]

JohninCR,

If you're trying to be a s**tdisturber, take it to JohnR.

As far as pawning myself off, my association with GR Research and RAW Acoustics is pretty clear and in plain English for anyone to read. My entire history (as pertaining to things audio) is here for anyone to peruse. No hidden agendas. Sorry.

Dayglow,

If you want to use language, then be a man about it, however, I'd suggest a different target because this one bites back.  Obviously you are aware of the new guidelines regarding those "in the audio business", yet choose to ignore them, so I shouldn't need take anything up with anyone.  Besides, anyone who has a website that spawns popup windows should be publicly flogged.  I went to your site once and ok'd the popup to open and got all kinds of crap, none of which included a price list for anything.

As far as pawning yourself off, that's exactly what you've been doing is trying to pawn yourself off as being objective, yet your clear business relationship obviously makes that impossible.  Whether it's in appearance or in fact is irrelevant.  When you are able to successfully dispute this simple point, then you can exclaim "nice try".  Until then your comments are irrelevant, and are a detriment to Danny's side.  Are you really unable to understand that?



Turbo,

I agree that there are some things to learn buried in this thread.  For those with real experience and understanding of measurements that best parallel sound quality, can we get back to that topic and stay there?  Then maybe this won't all be just a complete waste of everyone's time.  Come on guys, let's turn it into something productive.

[Daygloworange]

Come on guys, let's turn it into something productive.

Let's do that. I'd like to see this eventually turn into something postive. I've always wanted that.

Aside from that, JohninCR, I could care less of your personal opinions towards me or how you reach conclusions. I do think the experiments you do are way cool though. Honestly.

Cheers

[Daryl]

I have disagreed with Danny before about boutique capacitors.

He was nice enough to talk to me on the phone and offer to let me try some if I were interested.

Very nice gentleman indeed.

Regarding the Plastic Frame allegation, it is a plastic frame even if polymer were technicaly different than plastic you still would know what he meant and it would still be reasonable characterization.

That said I don't see a problem with a plastic frame unless it were likely to break, misalign or resonate which is not the case for this driver.

Regarding the Fake Phase Plug, it's a pointy former cap, John did not know what it was and I don't see any reason he should comment about it.

Regarding the 5.5khz Breakup Node, It is clearly visible in both FR and CSD charts and it's a mode not a node.

It is not that bad and it doesn't mean the GR M130 isn't an excellent driver.

There is no such thing as a "change in amplitude" without stored energy.

Anytime a frequency domain transfer function is not straight it will show up as energy storage.

Impulse/time domain response is exactly the same thing as frequency/phase response just another way of displaying it.

Breakup is slang for the surface of a driver "breaking up" into separate vibrational regions at high frequency instead of vibrating all at once like it would at low frequency where the speed of sound is fast enough for the entire diphram surface to be syncronized.

A breakup is also a resonance and they can have different Q's.

A metal cone simply has higher Q resonances than soft cones and that is well known.

The CSD for the M130 is the worst of the three in the 5.5khz region.

All three drivers are showing some breakup though.

Regarding the 1900hz suckout, It does not appear in Johns measurements and he doesn't say or show how he observed it so it probably is a mistake.

He say's it doesn't apear in smoothed measurements and I say nothing does if you smooth them enough so what's the point.

He also say's it doesn't appear in gated measurements.

A gated measurement is the response unless an anomaly has a bandwidth too narrow for your window length.

Very likely the 1900hz anomaly is the result of off axis, nearfield or an unwindowed measurement in a live environment.

Regarding Johns distortion measurements, they look to be in league with the other drivers in the test so whats the problem?

It was put forth that a distortion measurement can't tell you how a driver sounds and I don't know why it should.

More distortion might sound better but the object is to reproduce a signal unaltered so I don't see measuring how a driver will sound as tangable or usefull.

A distortion measurement tells you the amount of distortion (go figure) and less is better.

You could better compare drivers with a battery of distortion measurements at different levels as some have pointed out already.

You guy's should be able to work this out as Danny has suggested already.

Daryl

[ShinOBIWAN]

JohninCR,

If you're trying to be a s**tdisturber, take it to JohnR.

As far as pawning myself off, my association with GR Research and RAW Acoustics is pretty clear and in plain English for anyone to read. My entire history (as pertaining to things audio) is here for anyone to peruse. No hidden agendas. Sorry.

I agree with JohninCR. Its been in my mind since I joined this thread. Your contribution here is questionable at best considering.

[ShinOBIWAN]

If the instigators like yourself could let go of your need for internet drama, you might learn something.

No, not an instigator but I certainly helped fuel things a little which is pretty much inevitable with any like this, despite intentions otherwise. We've been arguing just who that was - John, Danny or the people that misconstrue information. I think most folks will look at this and realise it was all of those in some measure.

Are you really that big a baby?  Is John?  I doubt John is, but you're sounding that way ...

Your right Turbo, a few folks have already said more than enough, so I'll STFU.

[Danny Richie]

ShinOBIWAN, DGO, and JohninRC need to lay off poking at each other.

He may be as nice as can be in person, but in my limited experience in the forum has been the opposite, with an unwarranted condescending attitude toward me, combined with not doing what he said he would do.

Well if I have been condescending towards you in any way I certainly apologize. Secondly if I didn't do what I said I'd do for you then please shoot me off an e-mail and let me know what it is and I'll do whatever I can.

Dave, while no one has commented on your post. It certainly speaks volumes. Thanks for contributing.

Danny helped run a digital amp comparison in 2006, Kevin's amp(Exodus Audio) was in the group. It looks as if instructions weren't followed that Kevin provided to ensure the amp was running correctly. After rather poor results were published this came to light, Kevin explained and yet Danny, knowing that he was publishing potentially false/inaccurate information, still left the results on his website for all to see. Looks like it hurt Kevin's business a little.

It didn't happen that way and that is NOT accurate.

That means everything that Danny designs is suspect too. Do you think he has an anechoic chamber?

I had one for several years. It was 21 feet long. Want to see some pics?

Still, it's clear from the bulk of this thread that you guys don't really understand the nature of the measurements, how they are interpreted, what is accurate and what is not. Dan's comments, while not incorrect, are quite cursory.

And you are referring to who?

It is of note that the distortion measurements that John and I do are not done nearfield. a balance is struck between issues with reflections and resolution loss and nearfield artifact.

WOOOOOOOO, man are you kidding? Now the distortion measurements are far field? Now you are really opening yourself up for inconsistency. Number one, you guys need to state the way the measurements are taken so that known limitations can be taken into consideration. What's bad is the average guy has no idea what the limitations in accuracy are and if you don't explain it then more value is given to something that deserves little or no value at all. You might as well be taking these measurements in the back of a van while it's going down the road. You'll be lucky to get two measurements of one woofer that even look the same.

I might have to post some measured distortion levels done in room, and in distances outside the near field, to show the problems of doing this.

At this point, there is not much to be elucidated from this exchage. I will withdraw to my lab and library. Expect a reanalysis of the M130, a further comparison, and a more detailed, and, hopefully witty reparte on the rather superficial and often incorrect analysis you have provided. Still I have a full time job, a wife and kids, as well as a rather large laminate and travertine floor to finish, so it will take 2-4 weeks. The thread will probably be dead; I won't forget however.

If you are doing that to learn something that's great. I'll be glad to compare notes with you, and help in any way that I can. No condescension attended either. The offer is genuine.

If your are going to the trouble in some get even attempt then don't bother. No measurements that you can take are going to support your friends attitude and negative comments, and that is really what got us here.

Nice of you to join Daryl,

Regarding the Fake Phase Plug, it's a pointy former cap, John did not know what it was and I don't see any reason he should comment about it.

Come on now. I think it's pretty obvious there is intent to demean. If not he would have corrected it when asked. I really don't think he was that stupid to not know that it was a dust cap.  John is a pretty sharp guy with a chip on his shoulder.

There is no such thing as a "change in amplitude" without stored energy.

Daryl, you know that amplitude can change without stored energy. I have seen plenty of rising responses that were not due to stored energy. A dip is another type of change. So is baffle step loss (yea I know not driver related).

The CSD for the M130 is the worst of the three in the 5.5khz region.

I don't think so. If it was worse then it would have a longer decay time. It had the cleanest decay rate of the three woofers tested. If stored energy and inertia take longer to decay then that is worse.

You guy should be able to work this out as Danny has suggested already.

You are really right on there Daryl. Working it out would have been pretty easy I would have thought. If it wasn't for the demeaning verbiage used and a nasty e-mail response, we wouldn't be here now.

[ShinOBIWAN]

Danny you ought to let it go now. John isn't going to enter into the discussion, lots of people are assuming and nothing has been resolved to your satisfaction otherwise you wouldn't still be beating on the subject.

[Danny Richie]

I am just responding to what I feel I need to. I think there is also some more useful information to share and discuss on the technical side that many can learn from. I'll post more later on taking distortion measurements in the far field.

[Danny Richie]

Okay time for some more real data.

I have taken some distortion measurements of two different woofers. These are taken at 1 meter. Since taking measurements this far away makes it impossible to separate them from ambient room noise, I have cranked the gain up quite a bit so that I can create as large of a differential between the speaker and the room noise as I can. Also due to the inconsistences between taking measurements this way I have taken three measurements of each woofer to give you an idea of the range that they fall in. As you can see there is no sense in getting hung up on a specific peak unless it is there in all three measurements.

Everyone please have a look and compare them. Then let me know what you get from these. I don't care if you are an expert or have no idea. Please post your feedback. I'd like to know impressions. Which of these two woofers looks the best? Which will sound the best? Woofer one or woofer two?

Woofer one is always Red, Orange, Yellow.

Woofer two is always Green, Blue, Purple.

Here are second order harmonics:




Here are third order harmonics:




Here are 4th order harmonics:




And here are 5th order harmonics:

[dlr]

Number one, you guys need to state the way the measurements are taken so that known limitations can be taken into consideration.

I'm not sure of exactly how they've detailed their methods, but on this I can agree. Full descriptions of the test the test conditions help in understanding what it being done.

What's bad is the average guy has no idea what the limitations in accuracy are...

I can also agree here.

...and if you don't explain it then more value is given to something that deserves little or no value at all. You might as well be taking these measurements in the back of a van while it's going down the road.

No. You're making a judgement not based on full knowledge. Were you to say "MAY deserve little or no value if there are issues...". You are jumping to a conclusion not yet supported by fact.

You'll be lucky to get two measurements of one woofer that even look the same.

Again, a pre-conceived conclusion not supported by facts. Wait until you know all the details before making any conclusions, otherwise some may see you  as you see zaph.

I might have to post some measured distortion levels done in room, and in distances outside the near field, to show the problems of doing this.

This could be enlightening.

Regarding the Fake Phase Plug, it's a pointy former cap, John did not know what it was and I don't see any reason he should comment about it.

Come on now. I think it's pretty obvious there is intent to demean. If not he would have corrected it when asked. I really don't think he was that stupid to not know that it was a dust cap.  John is a pretty sharp guy with a chip on his shoulder.

I have one question here. Is the "phase plug" not metallic? If not, that be the basis for John's opinion of it. Typical "phase plugs" are metal to aid in reduction of motor distortion, something that a non-metallic one is not capable of doing. A metallic one also aids in the conduction of heat away from the pole-piece. I suspect that a non-metallic one also cannot aid in this manner. A fixed, non-metallic phase plug would eliminate the air-space resonance that would exist under a dust cap and might even extend the upper frequency a bit, but it will be far less effective in the overall scheme of usage of phase plugs. In that regard, John would be justified, but he could have used less flagrant terms.

Or am I wrong in my understanding of the material of the phase plug?

There is no such thing as a "change in amplitude" without stored energy.

Daryl, you know that amplitude can change without stored energy. I have seen plenty of rising responses that were not due to stored energy. A dip is another type of change. So is baffle step loss (yea I know not driver related).

Yes, while I agree with you here, what is seen at 5.5K is not a simple "rising reponse". It is very characteristic of a resonance. I'm not aware of any other way for a very symmetric peak such as that to exist in a raw driver. If you disagree, please explain exactly what creates that peak, specifically in the structure of the driver.

[Mark K]

Danny,

Please do post pictures of your anechoic chamber. While it is certainly reasonable to assume you've used one, having your own is an extremely expensive proposition. Most of the smaller loudspeaker manufacturers do not have a true anechoic chamber d/t cost issues. GR must be grossing much more than I imaged.

All the details of my measurement conditions are posted within my site. You either have not read my site in any depth or did not comprend it.

Obviously my measurements have limitations, as do yours. I have made a reasonable effort to put this forth. I have taken more than average care not to malign drivers. I have resisted the urge to come up with some sort of leaderboard exactly for this reason. Most driver choices are application specific and many drivers can be used given a particular set of design criteria.

Quote
"What's bad is the average guy has no idea what the limitations in accuracy are and if you don't explain it then more value is given to something that deserves little or no value at all."

There you go again, being somewhat condescending. You can't help it. This is how a marketeer and not a scientist would look at it. On the other hand, Zaph and I are trying to give useful additional information about drivers, as well as improving our knowledge base. I believe the average guy is quite capable of understanding the majority of our measurements. Sure, some folks don't have a clue. They need to work harder. Buy some reference texts, get some reprints, solve some problems, take some measurements and decide for themselves.

Am I trying to get even? Hardly. At this point my only concern is that folks will read this thread and feel that it's not worth looking at my or Zaph's measurements.

The only further comments at this point will be a general explanation and defense of our measurement techniques. And again, it will take some time.

edit-re your measurements while I was typing-Care must be taken not to let room reflections contaminate the measurments. I'll be happy to give more tips if you like.

[JoshK]

What do the different lines on each chart (e.g. Red/Orange/Yellow or Green/Blue/Purple) represent?  What is Red, what is orange and what is yellow?

NM, I get it now....each represents a different subsequent measurement. 

What type of signal was used for measurement?  What size of baffle?  Was the mic fixed for all measurements or what it moved in between subsequent measurements?   What level did you use to test at?

[RAW]

Woofer one is always Red, Orange, Yellow.

Woofer two is always Green, Blue, Purple.

Here are second order harmonics:

[speedle]

But where's the fundamental?  While not germain to your point, it would make the graphs look like (others) graphs that have been posted on the net. 

[speedle]

OH, and I meant to add, well what DID or DOES cause variations like that?  Random room noises? 

[Hank]

Okay I'll take a novice stab at this, probably wrong:  Woofer #1 will sound "worse", because it has more/higher peaks of odd-order harmonics above 70dB.  A lot of the over 50 dB might be heavily weighted with ambient noise.  Actually, the far-field tests are so varied, that I'm sure they can't predict the sound quality of either driver.

OH, and I meant to add, well what DID or DOES cause variations like that?  Random room noises?

Yes, I think he's trying to show how random ambient noise will cause changes in far-field driver response signatures, highlighting the limited viability/reliability of such measurements.  I might just buy a pair of drivers and send them to a professional anechoic chamber for testing.  Could be enlightening.

[Danny Richie]

dlr,

Or am I wrong in my understanding of the material of the phase plug?

It's NOT a phase plug at all. It's just a dust cap. The shape is a little longer (or taller) than most. It yielded the best overall response of all those that were tested. He was just being derogatory. There is a picture of the driver in my avatar.  

Yes, while I agree with you here, what is seen at 5.5K is not a simple "rising reponse". It is very characteristic of a resonance. I'm not aware of any other way for a very symmetric peak such as that to exist in a raw driver. If you disagree, please explain exactly what creates that peak, specifically in the structure of the driver.

Yes there is a peak there caused by a resonance. But the decay rate of the resonance is very fast and little stored energy is there. The decay rate is faster and looks cleaner than the other two drivers tested and compared to. All looked good, but mine was the one made to look bad in the comments. Again his attitude towards me may have had everything to do with that.

While it is certainly reasonable to assume you've used one, having your own is an extremely expensive proposition. Most of the smaller loudspeaker manufacturers do not have a true anechoic chamber d/t cost issues. GR must be grossing much more than I imaged.

Yes, I had my own. A couple of years back I sold the 5,200 square foot building that I owned and moved out. I decided I really didn't need prime commercial property to operate a business that wasn't even open to the general public. While I do miss the chamber I can really get by without it.

All the details of my measurement conditions are posted within my site. You either have not read my site in any depth or did not comprend it.

I am sorry but have not been to your site too much. I think I saw it from a link several years ago and recently visited it yesterday.

Obviously my measurements have limitations, as do yours. I have made a reasonable effort to put this forth. I have taken more than average care not to malign drivers.

And I think its good that you do that and it has merit, as does John's page. I feel some things are more valuable than others, but good none the less. By contrast you seem willing to communicate, you haven't called anyone names (other than condescending), you haven't bashed anyone that I can see or know of, or sent out nasty e-mails to me or others (that I know of).

There you go again, being somewhat condescending. You can't help it.

I am sure you think that but it is not my intent!

I believe the average guy is quite capable of understanding the majority of our measurements. Sure, some folks don't have a clue. They need to work harder.

See, you even agree yourself that some can not understand the measurements. Saying that they need to work harder could be considered condescending too.

The average Joe will no more understand your measurements or John's than the ones I just posted.

The only further comments at this point will be a general explanation and defense of our measurement techniques.

You don't have to "defend" your measurements. Just state the limitations, pro's and con's... Without a chamber to measure in its your distortion measurements that will have limited accuracy, and just say so and let it be. Explain the limitations and effects of room noise etc. Everything else you should be able to do with fairly good accuracy.

edit-re your measurements while I was typing-Care must be taken not to let room reflections contaminate the measurements. I'll be happy to give more tips if you like.

Yes I know. I have already stated that. So knowing that fact is there any value in the measurements that I posted? What can they tell you?

[Danny Richie]

What type of signal was used for measurement?

Sinusoidal.

What size of baffle?

8" wide and 12" tall.

Was the mic fixed for all measurements or what it moved in between subsequent measurements?

Mic distance stayed the same each time.

What level did you use to test at?

Sinusoidal won't allow me to dial in a wattage as easily as with a MLS or RTA measurement. It was however fairly loud to give me as good of a signal to noise ratio as possible.

Random room noises?

 

Yes, much of the variance is cause by room noise. The distortion levels are so low that they are in the room noise range and are not easy to pick up. The closer to the speaker you get and the louder you play it the greater the level of speaker distortion compared to the noise level. Getting too close though will cause near field response anomalies as Dan Wiggins and I have already illustrated with posted measurements. Getting accuracy outside of a chamber is pretty tough and must be taken as such.

Thanks Hank for the response to the posted measurements. Who else would like to take a stab at it? Come on guys what do YOU get from it? There is no wrong answer.