Measurements Vs. Sound

Mark Seaton said:

Hi Jeff,

When we add the differences between the two speakers in how they radiate sound into the room, their internal or structural resonances and even diffraction off enclosure edges we find many contributing factors toward very different subjective results in the same room and position.

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I agree with your whole post, but this sentence is particularly interesting. Even from a designer standpoint, we know the best ones listen. Doug Schneider has a feature coming with Kevin Voecks and Laurence Dickie and they both describe the design process which involves a lot of computer work. But then there are always those last few percentage points derived from listening. Regular audiophiles should learn the measurement side, and of course listen. Roll it all up in a ball and you'll end up with a better system. In my case that was true.

caesar said:

Do the Magico guys have any ideas about this?

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I certainly can't speak for Magico, but one thing that was said to me was that as their speakers got better and better in the Q development process (improvements in cabinet, drivers, etc.), they could hear more and more. The Q cabinet is reported to be far superior -- virtually silent. And that lets you hear more. All I can say is that after listening to the Q1 I would not want to even audition the Mini II in my room (because I would know how throughly it has been surpassed).

Jeff Fritz said:

I certainly can't speak for Magico, but one thing that was said to me was that as their speakers got better and better in the Q development process (improvements in cabinet, drivers, etc.), they could hear more and more. The Q cabinet is reported to be far superior -- virtually silent. And that lets you hear more. All I can say is that after listening to the Q1 I would not want to even audition the Mini II in my room (because I would know how throughly it has been surpassed).

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And after you audition the Q1 in your Music Vault the next question will be : how did it sound with some top subwoofers?

microstrip said:

And after you audition the Q1 in your Music Vault the next question will be : how did it sound with some top subwoofers?

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I have not reviewed enough of the top monitors to be able to provide context for it. So not me.

I should have the Q3 in a few weeks though. There are several other very promising floorstanders between $20k-40k also coming from now to over the summer.

John Atkinson's 2/17/10 review measurements of the Playback Designs MPS-5 revealed less than stellar technical performance even though Michael Fremer really liked the player. This is an example of audio measurements not agreeing with subjective listening. I've included JA's closing measurement remarks below followed by the manufacturer's comments.

To my knowledge there was never any followup in Stereophile regarding the manufacturers reply the MPS-5 could not be adequately measured with traditional measurement techniques.

Len
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Early on in the testing of the Playback Designs MPS-5, worried that there was something wrong with our review sample, I took the cover off to check that all the ribbon cables were seated properly (they were) and that there was nothing obviously adrift (there wasn't). So while I was impressed by the player's standard of construction, I can't say the same about its technical performance. The relatively high level of background noise limits the MPS-5's resolution with SACD and external 24-bit data to not much better than 16-bit CD. I am puzzled, therefore, why Michael Fremer liked the sound of this player so much. Perhaps his description of its sound being "analog-like" is a clue—for reasons that are not fully understood, a signal with very-low-level random noise added is sometimes preferred, on that it is more intelligible, to the same signal without such noise.1 But I feel that the MPS-5's measured performance precludes an unreserved recommendation.—John Atkinson
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Editor: We would like to thank both Michael Fremer and John Atkinson for the time and work they put into reviewing and testing our Playback Designs MPS-5 SACD/CD player. We were very pleased that an analog lover like Michael would enjoy our digital player.

Most of the measurement results are generally to be expected from the way they were measured. What differentiates the D/A converter inside the MPS-5 from other, more conventional converters is that it uses all custom algorithms and discrete components that were not designed following classic theories and practices. A large percentage of your charts show the behavior of the MPS-5 in the frequency domain, and only two charts show the time domain, although with rigid sinewaves as test inputs. While this would be totally adequate in most cases, it isn't for the MPS-5. For instance, most of the filter algorithms inside the MPS-5 cannot be described or even defined by feeding them periodic test tones such as sinewaves and looking at frequency charts. They were designed for real music signals, and therefore "listen" to the input signal and vary accordingly, to take advantage of how our ear perceives music, which never even resembles periodic test signals. It is common knowledge that such psychoacoustic criteria hardly ever lead to ideal measurements based on steady-state test signals.

Right from the beginning, the design goals for the MPS-5 were to reach new heights in sonic performance with real music signals rather than optimum test-signal measurements. The result is that the algorithms may not perform optimally from a measurement point of view when they have to process test signals, but, as your review also confirms, they do their assigned job quite well when processing real music signals. As we are always researching new ideas, the next-generation algorithms may very well make these kind of measurements even worse—but we can assure you that it will be for the benefit of sonic performance. Isn't that what we are all after?

Again, thank you for the wonderful review!—Jonathan Tinn, Andreas Koch
Playback Designs

Matt193, Jeff, Mark, and company,

Very informative thread...terrific!