And apparently, measuring loudspeakers in a room is futile because mikes don't capture the reflections arriving at different times, from different angles. We should only measure loudspeakers outside - like Linkwitz advocates.

It would be nice to measure *distortion* in loudspeakers, inc. harmonic and intermodulation. But I don't think Toole talks about this...or does he ?

I wouldn't go that far, with regards to always measuring outside. After all, we listen in rooms. It is very illustrative to go and listen to the speaker outside the room, to get a handle on the total signal.

I have an advantage, though. My Biz partner builds anechoic chambers. The other advantage is all rooms we use for evaluation and listening are inherently balanced, sonically - as he does this for a living.

Loudspeakers sound quite bad in anechoic chambers, as I'm sure you know. The main reason ? No reflections !! And this is why having uniform (and slowly decaying) reflectons from a speaker is so important....

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Loudspeakers sound quite bad in anechoic chambers, as I'm sure you know. The main reason ? No reflections !! And this is why having uniform (and slowly decaying) reflectons from a speaker is so important....

I have heard this stated many times. But never by anyone who has actually done it.

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I've always thought that Floyd's work was fabulous.

But...(there's always a 'but')...when it comes to audiophiles, specifically those who design speakers....we tend to disagree, to some extent -with Floyd. Why? If the audiophiles have a case, where did Floyd's analysis 'fall down'? When it comes to the highest fidelity and audiophile listening.... where was the misstep?

Here it is:

'Behind Acoustically transparent screens'

'Behind Acoustically transparent screens'

'Behind Acoustically transparent screens'

'Behind Acoustically transparent screens'

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Any loudspeaker designer and about 15 or more years of stereophile testing on this, will flat out tell you that there is no such thing as an 'acoustically transparent screen'....

Period.

This means that beyond basic direct radiative sonic attributes, nothing behind a 'screen' can be evaluated to anything like an even basic audiophile standard.

This has been well known for a considerable amount of time.

Maybe he did it with the grills off.

I always thought the other Toole was coole- John Kennedy.

A Confederacy of Dunces won the Pulitzer.

But he was already deceased.

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Loudspeakers sound quite bad in anechoic chambers, as I'm sure you know. The main reason ? No reflections !! And this is why having uniform (and slowly decaying) reflections from a speaker is so important....

I have heard this stated many times. But never by anyone who has actually done it.

If you remove enough noise from the speaker - then the reverse is true.

Speakers suffer from tremendous levels of noise, BTW,-just so that is clear. I don't know of any speaker that can achieve even a minimal 20db wideband S/N.

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I always thought the other Toole was coole- John Kennedy.

A Confederacy of Dunces won the Pulitzer.

But he was already deceased.

That was a GREAT book. Funny as hell, too, rare for literary fiction...

I spent the whole book disliking Ignatius Reilly, then I was totally depressed that the book ended.

That's one of the books I give as a gift.

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Loudspeakers sound quite bad in anechoic chambers, as I'm sure you know. The main reason ? No reflections !! And this is why having uniform (and slowly decaying) reflectons from a speaker is so important....

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I have heard this stated many times. But never by anyone who has actually done it.

Duke LeJeune does.

www.audiokinesis.com

The Jazz Modules offer a somewhat unorthodox approach to realistically recreating natural timbre and dynamic contrast over a fairly wide listening area in a reasonably-sized package.

Natural timbre arises from smooth frequency response, but to really get the timbre right requires attention to both the on-axis response and the summed omnidirectional response. The summed omnidirectional response is often called the

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'Behind Acoustically transparent screens'

Any loudspeaker designer and about 15 or more years of stereophile testing on this,

I think you're confusing speaker grills with the acoustic screens used by Toole. They don't use speaker grill material for this. Correct me if I'm wrong, but I don't know of any Stereophile tests of acoustically transparent screens like this.

No effect can be completely eliminated. You always have to decide if the magnitude of an effect is enough to invalidate testing. Engineers make those kind of judgment calls all the time.

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will flat out tell you that there is no such thing as an 'acoustically transparent screen'....

Period.

This means that beyond basic direct radiative sonic attributes, nothing behind a 'screen' can be evaluated to anything like an even basic audiophile standard.

This has been well known for a considerable amount of time.

You seem to have elevated this into an absolute which I just don't think can be justified.

And you can just as easily turn this around: there are any number of sonic factors that if raised to absolutes like this would invalidate any testing done by the audio press. You can't use this kind of absolute reasoning as an argument, it just shuts down any inquiry at all.

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'Behind Acoustically transparent screens'

Any loudspeaker designer and about 15 or more years of stereophile testing on this,

I think you're confusing speaker grills with the acoustic screens used by Toole. They don't use speaker grille material for this. Correct me if I'm wrong, but I don't know of any Stereophile tests of acoustically transparent screens like this.

We investigated the behavior of grille cloth material in the early 1990s, when we were trying to design blind speaker listening tests. Even the most sonically transparent cloth we found, which was used by Snell for their speaker grilles, had a large effect on the listening room's acoustics when draped across the width of the room between the speakers and listeners.

In the end, we disguised each speaker by surrounding it with a vertical tube of grille cloth. This only had a small effect on the sound of each speaker but was much better with regard to the room's acoustics.

These blind tests are not yet reprinted in our free on-line archives, please note.

John Atkinson
Editor, Stereophile

I would think, that there is more than one way to skin a cat. You just blindfold the actual listeners, and then you don't have to worry about the material. Floyd and the gang are no dummies and I'm sure they have nit-picked on their methods for decades and done what they can to eliminate experimental error. The fabric used would fall under that category.

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And apparently, measuring loudspeakers in a room is futile because mikes don't capture the reflections arriving at different times, from different angles. We should only measure loudspeakers outside - like Linkwitz advocates.

It would be nice to measure *distortion* in loudspeakers, inc. harmonic and intermodulation. But I don't think Toole talks about this...or does he ?

The main reason we measure outside or in chambers, is to get good data. It has nothing really to do with how the loudspeaker sounds in that environment. It has everything to do with getting consistent and reliable data from the measurement.

Chambers are weird just standing in them let alone listening to loudspeakers. We live in a world with noises, and reflections. When you remove that stimuli, it can only be described as disturbing. You lose a sense of balance, and the loudest noise you hear, is of a slight buzzing in your ears. To call it strange is an understatement. ;-)

Toole doesn't really go into the non-linear distortion debate, which has been settled in a manner that wouldn't be popular among audiophiles. Basically, the threshold for the objectional nature of non-linear distortion is much higher than you would think, at least from the studies.

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I would think, that there is more than one way to skin a cat. You just blindfold the actual listeners, and then you don't have to worry about the material.

Except then they can't see the notepads on which they record their scores. :-(

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Floyd and the gang are no dummies and I'm sure they have nit-picked on their methods for decades and done what they can to eliminate experimental error. The fabric used would fall under that category.

I'm sure you're right. But there is still the fact that almost all the blind testing one at Harman's facility is done in mono. This is optimal for detecting coloration and balance problems but not for stereo phenomena, such as imaging precision.

John Atkinson
Editor, Stereophile

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Except then they can't see the notepads on which they record their scores. :-(

I guess they will have to learn braille. ;-)

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I'm sure you're right. But there is still the fact that almost all the blind testing one at Harman's facility is done in mono. This is optimal for detecting coloration and balance problems but not for stereo phenomena, such as imaging precision.

John Atkinson
Editor, Stereophile

I was comforted by their studies on the detection of resonances and the fact that it is easiest to detect flaws or colorations due to resonances in a loudspeaker in mono.

Why? Because that is how I have been voicing my loudspeakers without the benefit of having a study to tell me it was the right way. I wish I could say it was because of my brilliance, but it is mainly because it is easiest to make changes to a design, in one loudspeaker, rather than two. It helps remove distractions when listening. The spacial characteristics are due mainly to the reflected sound and it actually distracts me from listening to see if it is tonally correct. After it is correct in mono, I find that it is always correct in stereo. The other direction is not necessarily true.

Same here. The only way, in my experience, to get the balance right and to get the transient alignment correct is to listen single speaker mono.