Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Audio Science Review of Expert 200.
@Confused

I'm not going to quote your long message but I will pick up on a couple of points.

In some ways one of the questions you're asking is about what measurements are relevant to what we hear and how relevant are they? Is every measurement equally relevant to what we hear. Does, for example, it matter whether an amp can deliver its full rated output on test tones at 19 and 20 kHz as one example of the relevance of a specific measurement.

So. taking the 19 and 20 kHz test tone question and looking at it from a practically objective viewpoint as opposed to a theoretically objective viewpoint, I'm going to say that it doesn't matter that an amp can't deliver full output at those frequencies. There are 2 reasons I have for saying that and they both relate to real world practicalities.

First, can most of us hear anything at those frequencies? The answer to that is no. While the human frequency range is quoted as extending from 20 Hz to 20 kHz, dig a bit deeper into the data on that and you find that we start losing the high frequencies very early in life and that the ability to hear 20 kHz is found only in the young with many being incapable of hearing 20 kHz at age 20 or so. We've got a poll here on the age of forum members and only 2.15% of respondents were under 34. Add the 3.82% aged between 25 and 30 and we/ve got less than 6% of respondents aged 30 or less. Over 50% are aged 45 or older. Most of us can't hear 20 kHz or anywhere near that.

Second, what content at 19 kHz and higher is present in music and at what level is it present? The highest fundamentals in music are between 7 and 8 kHz and everything above that is overtones which are at lower levels than the fundamentals. High frequencies are easily absorbed, even being absorbed by air, so the high frequency overtones we hear when listening to live music are down in level compared to the fundamentals anyway, simply because of distance and absorption in air. We listen to music at home from our speakers at much closer levels than we tend to listen to live music unless we play in a band or are sitting close to someone singing or playing so we can expect the level of the overtones at 19 kHz and higher to be higher in level relative to the fundamentals than they would be when we're listening to live music but even so the level of the high frequency overtones produced by voices and instruments is still lower in level than the fundamentals so the amplifier is never going to be called on to deliver enough power for any musical content at 19 kHz and higher to be delivered at the same sound pressure level as the fundamentals an octave and a half or more lower in frequency.

That leaves the question in relation to those 2 frequencies of intermodulation distortion, the reason for that particular test, because the IMD spectrum for those 2 frequencies is a distortion product at 1 kHz and at every 1 kHz above that. The simple fact, however, is that those distortion products are at much lower levels than the test tones and that means that they're also going to be at much lower levels than the actual content at those tones in music. In practice I suspect that the IMD products of those frequencies in music are going to be inaudible, especially given the IMD performance of Devialet's.

Put all of that together and the inability of the amp in ASR's test to deliver full rated output at 19 and 20 kHz is highly unlikely to affect our enjoyment of music because the amp is never going to have to deliver that output when playing music, even when it is delivering full output at frequencies where musical fundamentals are present, and because in practice most of us can't hear those frequencies anyway and the intermodulation distortion products of the frequencies in that range actually present in music are going to be inaudible in an amp with the Devialet's IMD performance

So what I'm saying is that not all measurements are equally relevant or important when assessing the performance of an amp in real life delivering music. Knowing what measurements are relevant and how important those measurements are is something most of us rely on the reviewer to tell us. You mentioned the test results of John Atkinson and Paul Miller and the fact that neither were overly concerned about similar measurements in their tests to those reported in the ASR review. In fact, my understanding is that Paul Miller actually uses a Devialet in his own system. Both Atkinson and Miller have extremely good reputations as reviewers, earned in part by their ability to relate their measurement results to what people are likely to hear when using a given product. Amir at ASR does not have such a reputation. I'm not questioning his measurements, the fact that both Atkinson and Miller measured similar things indicates that his measurements are probably in the ball park, but I would say that the fact that neither Atkinson nor Miller was overly concerned about their measurements is a lot more important than the actual measurement itself. Stereophile gave both the D-Premier and the 140 Pro an A rating and Miller apparently uses a Devialet himself. Actions speak louder than words as the saying goes, and those actions carry a lot more weight in my view than the ASR review's words.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
Reply


Messages In This Thread
Audio Science Review of Expert 200. - by ragwo - 30-Mar-2020, 16:30
RE: Au - by kerkhoffd - 30-Mar-2020, 16:38
RE: Au - by ragwo - 30-Mar-2020, 17:10
RE: Audio Science Review of Expert 200. - by David A - 18-Apr-2020, 23:45

Forum Jump:


Users browsing this thread: 2 Guest(s)