Martin Logan ESL series speakers??

[avaserfi]

Also I always wonder how many of the listeners in these perceptual tests really have a good frame of reference as to what the kind of music you are talking about really sounds like. Having made hundreds of live recordings over the years, you soon have a good idea if a speaker can make a reasonable attempt at recreating the original sound.

Typically, trained listeners are used in such perceptual studies. These listeners are trained in a variety of ways to note realism as well as various other aspects of loudspeakers.

While one might be suspect of trained listeners being used in such studies, due to bias created during training, this has been shown not to be an issue. Rather, it has been shown that through comparison of various subgroups of untrained listeners to trained listeners that there is no statistically significant difference in loudspeaker choice or description. The largest differences found where in variance [with untrained listener variance being higher] and time listening needed to arrive at such conclusions. Also, occasionally trained listeners are more critical of a loudspeaker being auditioned when compared to untrained listeners. One other interesting aspect was that untrained listeners could be trained relatively quickly [under five listening sessions] decreasing variance significantly.

Olive, E. Sean. Differences in Performance and Preference of Trained vs Untrained Listeners in Speaker Tests. J. Audio Engineering Soc., Vol. 51, No. 9, 806 - 825, September 2003.

 

[jostenmeat]

I wonder what % of those listeners, if I was to put on any of my vocal motets/masses/sequences, could tell me how many vocal lines there were in any movement.

I'm dead serious.

 

[TLS Guy]

I wonder what % of those listeners, if I was to put on any of my vocal motets/masses/sequences could tell me how many vocal lines there were in any movement.

I'm dead serious.

I'm just very suspicious of the whole process. The listeners seem to show preference for omnipolar speakers. First off a moving coil omnipolar speaker does not exist. Any attempts I have heard at producing one sound simply awful.

There is just no technology out there that could produce such a thing at present. Moving coil speakers pointing in different directions, or worse tweeters hung in front of loudspeaker cones facing upwards are really the pits.

I agree, I bet few if any of the listeners could identify the vocal parts, and I bet a lot of the speakers under review would not let them!

 

[avaserfi]

I'm just very suspicious of the whole process. The listeners seem to show preference for omnipolar speakers.

The majority, if not all, of the perceptual research deals directly with monopolar speakers and correlating listener preference to measurable aspects.

The reason for the step towards properly constructed omnipolar loudspeakers can be first seen in Toole and Olive's work with resonance and their thresholds. One of the many conclusions of this research was that resonances from both the loudspeaker [bad] and the source material [good] were more audible when in a reverberant space. Thus, a monopolar speaker with a wide dispersion pattern and low resonances would ideally not have its first reflections, relative to the listener treated to allow for increased timbre information. The next logical step is using an omnipolar loudspeaker adding additional first reflections and more timbre information. Please note the first reflections should ideally arrive to the listeners ear within 4-10ms of the main signal for optimal results.

Any attempts I have heard at producing one sound simply awful.

There are a few two main reasons for this:

- Poor design: Plain and simple, there are very few high quality omnidirectional speakers on the market and none of the high quality units of which I am aware are cheap.

- Improper placement/Room acoustics: While it is well known having proper acoustics and placement is a huge factor for monopolar speakers it is exponentially more important with omnipolar speakers due to the wider dispersion patterns [increasing room interaction]. The required treatments for an omnipolar setup are not only vastly different, they are intrusive and typically would be perceived as ugly. This does not lend itself to anything, but a dedicated room. Even in dedicated rooms with omnipolar treatments I have seen virtually no rooms designed to maximize performance of an omnipolar so it would be perceived as superior to a monopolar unit.

 

[TLS Guy]

The majority, if not all, of the perceptual research deals directly with monopolar speakers and correlating listener preference to measurable aspects.

The reason for the step towards properly constructed omnipolar loudspeakers can be first seen in Toole and Olive's work with resonance and their thresholds. One of the many conclusions of this research was that resonances from both the loudspeaker [bad] and the source material [good] were more audible when in a reverberant space. Thus, a monopolar speaker with a wide dispersion pattern and low resonances would ideally not have its first reflections, relative to the listener treated to allow for increased timbre information. The next logical step is using an omnipolar loudspeaker adding additional first reflections and more timbre information. Please note the first reflections should ideally arrive to the listeners ear within 4-10ms of the main signal for optimal results.



There are a few two main reasons for this:

- Poor design: Plain and simple, there are very few high quality omnidirectional speakers on the market and none of the high quality units of which I am aware are cheap.

- Improper placement/Room acoustics: While it is well known having proper acoustics and placement is a huge factor for monopolar speakers it is exponentially more important with omnipolar speakers due to the wider dispersion patterns [increasing room interaction]. The required treatments for an omnipolar setup are not only vastly different, they are intrusive and typically would be perceived as ugly. This does not lend itself to anything, but a dedicated room. Even in dedicated rooms with omnipolar treatments I have seen virtually no rooms designed to maximize performance of an omnipolar so it would be perceived as superior to a monopolar unit.

The problem is that it all founders on the rocks of time and phase, my friend. I had a good discussion with Peter Walker about this once.

He used the analogy of calm pond. Throw one stone into the pond and the ripples go out in a perfect circular fashion.

Once you have drivers displaced in space, they are displaced in time and phase. Then you have multiple stones in the pond, one for each speaker. The result disaster. He did a lot of research on this problem during the development of the ESL 63.

 

[WmAx]

The problem is that it all founders on the rocks of time and phase, my friend. I had a good discussion with Peter Walker about this once.

He used the analogy of calm pond. Throw one stone into the pond and the ripples go out in a perfect circular fashion.

Once you have drivers displaced in space, they are displaced in time and phase. Then you have multiple stones in the pond, one for each speaker. The result disaster. He did a lot of research on this problem during the development of the ESL 63.

The phase response distortion, even to the degree of common 4th order L-R end target response crossovers, is audibly non-important for music program. This is the conclusion of the credible perceptual research, which tests these factors under blinded and randomized conditions. I have referred you to the specific research articles in the past, I believe, but you must not care about such research; since you only mention speculation by Walker.

-Chris

 

[WmAx]

I'm just very suspicious of the whole process. The listeners seem to show preference for omnipolar speakers. First off a moving coil omnipolar speaker does not exist.

Sure it does. Any speaker reproducing wavelengths less then 1/2 it's effective diameter, and with it' backwave isolated from the front wave, is by inherent definition, omnipolar up until that point. You only need 'upfire' the speaker, and it will behave as the perfect theoretical omnipolar until it's reaches this wavelength. But while this may be difficult for the upper most treble frequencies, you can over come this limitation with very carefully designed wave diffuser. Of course, you don't even have to use this configuration, nor a standard dynamic driver, for the treble. You can for example, use two back to back firing planar drivers with extremely narrow horizontal radiation areas, and the same acoustical loading in the environment will be accomplished as a 'true' omnipolar driver should produce.

Any attempts I have heard at producing one sound simply awful.

And any attempts at ANY speaker type sound simply awful to me 99.9% of the time. But even if you came across a proper omnipolar speaker, it is highly improbable that the environmental acoustics and speaker placement were set up properly to take advantage of the superiority such a design can produce in sound quality.

There is just no technology out there that could produce such a thing at present.

False. I have designed prototypes based on the above(using back to back firing drivers), and am currently producing design using this method that will be complete in November.

MBL has a commercially available loudspeaker that is a superb example of a full range omnipolar.

Moving coil speakers pointing in different directions, or worse tweeters hung in front of loudspeaker cones facing upwards are really the pits.

The depends on the specific implementation. Drivers facing upwards will work fine, when used within their limitations and/or with the appropriate well designed wave diffusers. If you are making such judgement(s) from say, the popular Mirage speaker line found in retail stores, this is hardly accurate, as these speakers have other serious flaws not even related to the diffuser, and in addition, I have NEVER seen one properly set up in a display. In fact, I can't think of a single over-all well executed full range commercial omni polar, except for the recent MBL units.

-Chris

 

[TLS Guy]

The phase response distortion, even to the degree of common 4th order L-R end target response crossovers, is audibly non-important for music program. This is the conclusion of the credible perceptual research, which tests these factors under blinded and randomized conditions. I have referred you to the specific research articles in the past, I believe, but you must not care about such research; since you only mention speculation by Walker.

-Chris

I could not disagree with that statement more. There is increasing evidence that time shifts greater then 1.5msec are undesirable. My own experience has taught me that a speaker with fourth order crossovers just have a strangeness about them. Piano is especially revealing.

Of course I have used fourth order crossovers, but they have never been my favorite. A speaker that turns a square wave into a sine wave, has to have problems with impulse reproduction and therefore have trouble with realistic musical attack. It is preposterous to maintain that an amplifier has to have the ability to reproduce a good square wave and then say it is OK for a speaker to turn it into a sine wave!

By the way Peter Walker did not speculate about this. Peter was one of audio's greatest researchers and engineers, with a litany of papers.

He was fascinated with sounds separated by a stretched mylar membrane.

If you are separated from another individual entirely by such a membrane, then your voices are unchanged. Your voices though are being perfectly reproduced by that membrane. This was a big focus of his studies, which he was trying to duplicate as perfectly as he could in the ELS 63.

If we could make a membrane vibrate in that fashion, then you would have virtually perfect reproduction. I can assure you the membrane is not vibrating with rigid pistonic motion.

 

[WmAx]

By the way Peter Walker did not speculate about this. Peter was one of audio's greatest researchers and engineers, with a litany of papers..

I will be glad to read his peer reviewed study using listeners in blinded tests that has been published in a credible journal such as JAES and stood up to valid scrutiny. If his studies are so valid, it is odd that this view did not stand up to the very carefully produced research studies using randomized blinded samples on actual listeners as is understood in the current state of knowledge.

In what is perhaps the ultimate irony, one of the most important published studies[1] used Peter Walker Quads for the test transducer for listeners(since the Quads have textbook perfect phase response); playing samples that were both unmodified and electronically modified to produce the typical phase distortion from multi-driver speakers, and yet, there was no significant difference found for music program in a listening room.

-Chris


Reference
[1] On the Audibility of Midrange Phase Distortion in Audio Systems
Stanley P. Lipshitz, Mark Pocock and John Vanderkooy
JAES, Vol. 30, No. 9, September, 1982, Pages 580-595

 

[TLS Guy]

I will be glad to read his peer reviewed study using listeners in blinded tests that has been published in a credible journal such as JAES and stood up to valid scrutiny. If his studies are so valid, it is odd that this view did not stand up to the very carefully produced research studies using randomized blinded samples on actual listeners as is understood in the current state of knowledge.

In what is perhaps the ultimate irony, one of the most important published studies[1] used Peter Walker Quads for the test transducer for listeners(since the Quads have textbook perfect phase response); playing samples that were both unmodified and electronically modified to produce the typical phase distortion from multi-driver speakers, and yet, there was no significant difference found for music program in a listening room.

-Chris


Reference
[1] On the Audibility of Midrange Phase Distortion in Audio Systems
Stanley P. Lipshitz, Mark Pocock and John Vanderkooy
JAES, Vol. 30, No. 9, September, 1982, Pages 580-595

I have no confidence in that study. It is time for a second look. This is what Linkwitz says on the matter.

I don't believe for a minute we can improve loudspeakers and be cavalier about time and phase. In fact as long as we continue to use separate drivers
dosplaced in time and space, it will preclude entry to the promised land.

 

[WmAx]

I have no confidence in that study. It is time for a second look. This is what Linkwitz says on the matter.

I don't believe for a minute we can improve loudspeakers and be cavalier about time and phase. In fact as long as we continue to use separate drivers
dosplaced in time and space, it will preclude entry to the promised land.

According to the link, Linkwitz really does not say anything - and in the end is rather neutral - with a slight bias towards not believing it has much relevance, based on the direct link you provided. Even so, Linkwitz did not make any references to the perceptual research in regards to the subject - and what is written on that link is not defending your perspective substantially.

Look up the AV University on the AH main site - there is a long article by Mark K.(a former Harman speaker engineer/consultant) on phase and it's relationship to audibility - with much discussion of the perceptual research involved in forming the present day conclusion(s).

-Chris