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Power Response and the Last Dates of the Magnepan 30.7 Road Tour

TitaniumTroy

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#1

In the video Wendell Diller of Magnepan explains about the importance of power response in trying to reach a more realistic stereo experience.
I might try to make some of these dates to hear the 30.7s in a different room than I did in Chicago. Plus I like talking to Wendell Diller in person, to talk about speakers and the audiophile world.
Aug 19 - Kazoo Audio, Kalamzoo, Michigan
Aug 21 - Ovation, Indianapolis, Indiana
Aug 23 - Sound & Vision, Columbus Ohio
Aug 24 - Hanson Audio, Cincinnati, Ohio

Needless to say, RSVP is required and dates may change.
 

amirm

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#2
Hmmm. Harman's research shows very poor correlation between power response and listening preference. So don't know why he says Dr. Toole's research indicates otherwise.
 

Ilkless

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#3
Hmmm. Harman's research shows very poor correlation between power response and listening preference. So don't know why he says Dr. Toole's research indicates otherwise.
I thought the poor correlation was, specifically, with the Consumer Reports target for flat power response. A smooth power response is still desirable - a sign of off-axis directivity control and matching.
 

Floyd Toole

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#4
The Magnepan description at 2:15 minutes or thereabouts, describing "Toole's" research is totally wrong - an outright lie. The first requirement of a good sounding loudspeaker is its on-axis response, second, it's early reflection response, and at low frequencies, its steady-state in-room response. Sound power by itself is a poor correlate of overall sound quality. It is useful because it is a component in the traditional metric of directivity index, and if it is smooth, it can help confirm the absence of resonances.

BS baffles brains, especially when people don't read and promoters of products are simply either ignorant or deliberately misleading. I suspect both in this case. He is using it only to get my name in there. It pisses me off !!!!
 
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TitaniumTroy

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#5
Hey I didn't know Dr. Toole posted on this site, that's really interesting and cool. I'm going to have to read what posts he has made in the past, thanks for your input Dr. Toole.
Troy
 
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Floyd Toole

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#6
You are welcome. I don't catch all offenses against scientific truth - they are numerous and widely distributed - but sometimes I get lucky. You should read my book, and then you can do your own policing of truths :)
 

dreite

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#8
Wendell has himself tangled up with the language quite a bit, but I think he understands what he was trying to get at. Maybe. :)
But, I can certainly understand why Floyd would have a problem with the description.

Even with that, I suspect the eyes were glazing over in the audience for much of that. :)

Dave.
 

Floyd Toole

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#11
Below about 500 Hz in normal - smallish - listening rooms bass performance is dominated by resonant standing-waves in the room. The room and the loudspeaker cannot be separated, so in-situ measurements must be made. As explained in great detail in Chapter 8 of the 3rd edition of my book, there are several ways to address this problem.
 

mitchco

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#12
Agreed. One way to address is using so called room eq. Here is a speaker that has had Audiolense DSP applied from 500 Hz and below. Top curve is the speakers's measured steady state in-room response. Up to 25 dB total variation in the low frequencies. Very audible. Bottom curve is with the DSP applied below 500 Hz, now within +- 3 dB. Bass response sounds much better! The frequency response above 500 Hz is left alone.

500 Hz partial correction.JPG
 

josh358

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#13
The Magnepan description at 2:15 minutes or thereabouts, describing "Toole's" research is totally wrong - an outright lie. The first requirement of a good sounding loudspeaker is its on-axis response, second, it's early reflection response, and at low frequencies, its steady-state in-room response. Sound power by itself is a poor correlate of overall sound quality. It is useful because it is a component in the traditional metric of directivity index, and if it is smooth, it can help confirm the absence of resonances.

BS baffles brains, especially when people don't read and promoters of products are simply either ignorant or deliberately misleading. I suspect both in this case. He is using it only to get my name in there. It pisses me off !!!!
Wendell was rushing to get out of the office for a well-deserved vacation, so he asked me to pass this along:


I regret that my remark has caused distress, and that it was apparently misinterpreted. My admiration for your contributions is genuine and, as with many loudspeaker manufacturers, has been beneficial to our design efforts. The last thing we want to do is misrepresent your work, either intentionally or not.

We at Magnepan go out of our way to avoid the kind of technical doubletalk that, unfortunately, is all too common in industry promotions. As I've stated often, we want our speakers to be evaluated on the basis of sound quality, rather than technical one-upmanship. What we say is the truth insofar as we understand it, and my long-time policy has marketing director has been to "undersell and overdeliver."

We didn't claim, nor do we believe, that power response is the primary determinant of loudspeaker quality; as you say, the most important characteristic of a good loudspeaker is good on-axis performance, and that was our first priority in designing and optimizing the 30.7. I chose to emphasize power response rather than on-axis performance in my North American tour for two reasons: one, it made for a more interesting demonstration, and two, because I know by experience that when the energy is uneven in a room, I am not convinced that it sounds like an orchestra.

Our loudspeakers wouldn't sell if we were indifferent to the technical properties that contribute to good sound, and your work has been an integral part of that effort. If my remarks were inaccurate or subject to misinterpretation, I apologize. It certainly was not my intent.

Wendell Diller
Director of Marketing, Magnepan
 
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