[ctviggen]

I don't think ETF helps for speech intelligibility.  Also, I think 8th Nerve's idea is based upon less distortion.  That's another item that's really not examined by programs such as ETF. 

[Ethan Winer]

Bob,

I don't think ETF helps for speech intelligibility.

ETF doesn't really help anything, it only measures what you have - frequency response, reflections, and decay times versus frequency. That's what matters in a room.

Also, I think 8th Nerve's idea is based upon less distortion.  That's another item that's really not examined by programs such as ETF.

Actually, ETF can measure distortion if you buy the add-on for that. But no acoustic treatment can deal with distortion anyway. Distortion is by definition nonlinearity, and nothing in a room adds distortion other than perhaps a wall or window that buzzes or rattles. Room acoustics is purely linear, so the use of the word "distortion" in that context is erroneous.

--Ethan

[IronLion]

Eighth Nerve products have really improved the sound of my room, don't know if the corners were causing distortion or there were little gnomes hiding up there shouting when I played music, but they really helped focus the soundstage. 

[8thnerve]

Also, I think 8th Nerve's idea is based upon less distortion.  That's another item that's really not examined by programs such as ETF.

Actually, ETF can measure distortion if you buy the add-on for that. But no acoustic treatment can deal with distortion anyway. Distortion is by definition nonlinearity, and nothing in a room adds distortion other than perhaps a wall or window that buzzes or rattles. Room acoustics is purely linear, so the use of the word "distortion" in that context is erroneous.

--Ethan

We'll have to agree to disagree on that.

[Glenn K]

Also, I think 8th Nerve's idea is based upon less distortion.  That's another item that's really not examined by programs such as ETF.

Actually, ETF can measure distortion if you buy the add-on for that. But no acoustic treatment can deal with distortion anyway. Distortion is by definition nonlinearity, and nothing in a room adds distortion other than perhaps a wall or window that buzzes or rattles. Room acoustics is purely linear, so the use of the word "distortion" in that context is erroneous.

--Ethan

We'll have to agree to disagree on that.

What????? Disagree with what part????


If you have the Everest hand book, turn to Acoustical Distortion chapter 25
page 486, that is purely linear. Am I missing something here? All this
time I thought you where talking about that. So your stuff fixes things like
amp distortion?

Glenn

[Ethan Winer]

If you have the Everest hand book, turn to Acoustical Distortion chapter 25 page 486, that is purely linear.

Correct Glenn, and I'll add that the chapter's title is in error because distortion by definition is nonlinearity. I know that some people use the term loosely, but that doesn't make it correct. The same goes for phase distortion, which people sometimes use wrongly to describe phase shift.

I also want to reiterate for IronLion that I'd never suggest the eighthnerve products don't work at all. I'm sure they do something to the sound of the room. But they cannot affect distortion of any sort unless they are adding distortion by buzzing or rattling etc as described above. Which I really doubt is the case. I'd email Dr. D'Antonio about his error, but he wrote that chapter many years ago and I'm pretty sure he now understands the word "distortion" is incorrect in this context.

--Ethan

[Glenn K]

If you have the Everest hand book, turn to Acoustical Distortion chapter 25 page 486, that is purely linear.

Correct Glenn, and I'll add that the chapter's title is in error because distortion by definition is nonlinearity. I know that some people use the term loosely, but that doesn't make it correct. The same goes for phase distortion, which people sometimes use wrongly to describe phase shift.

I also want to reiterate for IronLion that I'd never suggest the eighthnerve products don't work at all. I'm sure they do something to the sound of the room. But they cannot affect distortion of any sort unless they are adding distortion by buzzing or rattling etc as described above. Which I really doubt is the case. I'd email Dr. D'Antonio about his error, but he wrote that chapter many years ago and I'm pretty sure he now understands the word "distortion" is incorrect in this context.

--Ethan

Completely agree. When I first saw the chapter the first thing I though was "WHAT?", but then when I read the chapter it made sense. Basically things like comb filtering would fall under that and yes that is linear.
If you where to write that chapter what would you title it? The sound is distorted, but not like distortion you would find in my fender amp. 

Glenn

[Ethan Winer]

Glenn,

If you where to write that chapter what would you title it? The sound is distorted, but not like distortion you would find in my fender amp.

My background is in audio engineering so I tend to be a stickler for using correct terminology. If I were to name that chapter I'd call it Acoustic Faults or Room Effects or something similar. But certainly not distortion which, again, always implies nonlinearity.

--Ethan

[Glenn K]

I guess this guy feels the same way about it as you do.   
http://www.record-producer.com/learn.cfm?a=3527

Pretty clear and to the point.  aa

Glenn

[Ethan Winer]

I guess this guy feels the same way about it as you do.

Exactly. An EQ definitely changes the signal, but it doesn't add distortion so it's considered linear. If you boost 1 KHz or whatever by 3 dB, the same amount of boost happens whether the signal is loud or soft. This is the key. In audio, a device is linear if it does the same thing at all volume levels, and nonlinear otherwise. That's why a guitar amplifier is often considered nonlinear because it affects the sound differently at different volume levels.

--Ethan

[Glenn K]

Well said. 

Here is Peters definition which I would HIGHLY RECOMMEND everyone read. Ethan is right the word really is loosely used but I ain't going to be the one to fight with Peter about it. 

http://www.customaudiodesigns.co.uk/articles/rpgpaper.htm

Glenn

[Ethan Winer]

I ain't going to be the one to fight with Peter about it.

Yeah, sure, leave the dirty job to me. Thanks a lot.

But there's no doubt that Dr. D is using imprecise wording.

--Ethan

[Glenn K]

ETHAN WINER do I need to pull out the big guns on you?

[8thnerve]

From the American Heritage Dictionary:
distortion: 4. Electronics
1. An undesired change in the waveform of a signal.
2. A consequence of such a change, especially a lack of fidelity in reception or reproduction.

From WorldNet:
distortion: 4. a change (usually undesired) in the waveform of an acoustic or analog electrical signal; the difference between two measurements of a signal (as between the input and output signal); "heavy metal guitar players use vacuum tube amplifiers to produce extreme distortion"

From Dictionary.com:
distort: 3. Electronics. to reproduce or amplify (a signal) inaccurately by changing the frequencies or unequally changing the delay or amplitude of the components of the output wave.

Have an opinion about what qualifies for distortion if you'd like, but the definitions are fairly clear.  The corners change the signal, and they do not change the signal equally at all frequencies, as any horn loading cabinet will show you.  Sounds like the definition of non-linear to me.  (although non-linearity is not a necessity of distortion according to all these references)  I'm not sure how many times I have to note that you won't find this information in Everest's "bible."


"I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives." - Leo Tolstoy

[Glenn K]

Nathen,

 

distortion: 4. Electronics
1. An undesired change in the waveform of a signal.
2. A consequence of such a change, especially a lack of fidelity in reception or reproduction.

Key word here is Electronic and acoustics are not.

distortion: 4. a change (usually undesired) in the waveform of an acoustic or analog electrical signal; the difference between two measurements of a signal (as between the input and output signal); "heavy metal guitar players use vacuum tube amplifiers to produce extreme distortion"

Key word here are electrical which acoustics are not.

From Dictionary.com:
distort: 3. Electronics. to reproduce or amplify (a signal) inaccurately by changing the frequencies or unequally changing the delay or amplitude of the components of the output wave.

Once again key word is electronics.

Are you sure you are talking about distortion as it relates to Everest's book?

Glenn

[Ethan Winer]

The corners change the signal, and they do not change the signal equally at all frequencies

Okay, but the key to nonlinearity and distortion is not change versus frequency but rather change versus amplitude. Phase shift affects different frequencies differently, but it's not distortion or nonlinear because it affects all volume levels equally. Likewise for an equalizer, as I already explained.

I'm not sure how many times I have to note that you won't find this information in Everest's "bible."

I think this is what bothers me most about your looseness with the science of audio. You have stated several times that your products and methods cannot be tested using conventional techniques. There is nothing in the field of audio that cannot be tested using conventional techniques! You say your products don't work via absorption, but you offer no alternate explanation other than to say they're "not old science" which to me smacks of "new physics." Again, I'm not trying to pick a fight or denigrate your products. I'm sure they have some positive effect. But here's the key part I'd love you to explain:

If the effect of your products is not the result of absorption, then please state clearly the exact scientific principle by which a relatively small piece of material can flatten the response and reduce modal decay times at frequencies as low as 40 Hz.

--Ethan

[Big Red Machine]

Soon I may start another thread about the continuing saga of my room.  I have been feverishly remodeling the room under Bryan's guidance.  We had a chance to speak face to face at RMAF and the lightbulb went off due to Bryan and now I know what needs to be done.

I have dismantled the old room and rotated it 90 degrees, tore down all the treatments and reengineered them.  Dismantled my rack and started making amp stands.  Ordered new amps, new IC's, new rack (storebought - oh my!), and am going after much improved sound.  I'm excited!

[8thnerve]

Let me see if I can explain it this way.  Let's say that this acoustic distortion or whatever you want to call it is an 800 pound gorilla.  In order to deal with this huge gorilla, we'd need lots and lots of material and trapping to control him, right?  My approach is to take a time machine back to when he was only an 80 pound gorilla and deal with him then.  Then we never have to face the 800 pound gorilla he will become.

By trapping the return wave from the corner, we eliminate the sounds waves that become large acoustic problems once they propagate into the room.  At the time they are trapped, they are still small and easy to deal with, and I am able to use smaller materials which can eliminate them before they become large problems and need huge amounts of material and surface to deal with.  Does that make sense?

And yes, I realize the definitions for distortion are given in an electronics context, but the same type of non-linearities happen acoustically which I why I use the term.

Best,

Nathan

[Glenn K]

By trapping the return wave from the corner, we eliminate the sounds waves that become large acoustic problems once they propagate into the room.  At the time they are trapped, they are still small and easy to deal with, and I am able to use smaller materials which can eliminate them before they become large problems and need huge amounts of material and surface to deal with.  Does that make sense?

 

Best,

Nathan

Sorry but no that does not make any sense.
Would you mind pointing me to some technical writing that explains this new science? The reason acoustics have to be the size that they are is to pick up the sound. Until someone comes up with a product that can attract sound to it then size does matter.

Glenn

[JohnR]

In general, it's better if Industry Participants do not take shots at each other in the open forum.

Things are already tenuous enough with the commercial activity going on in this supposedly non-commercial circle.

Thanks

JohnR