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In Reply to: RE: BTW posted by Pat D on December 09, 2014 at 20:15:00
...show it to us and the measurements to prove its accuracy.
Follow Ups:
That's easy enough.
http://www.stereophile.com/content/bryston-7b-sstsup2sup-monoblock-power-amplifier-measurements
http://www.soundstagemagazine.com/measurements/bryston_4b_sst/
http://www.soundstagemagazine.com/measurements/simaudio_moon_w6/
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"A fool and his money are soon parted." --- Thomas Tusser
Looking at the Bryston, it does not measure to be a straight wire with gain to the limits of the measurement equipment used. This is objective evidence that the amplifier is not "accurate".
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Nothing of human manufacture is absolutely perfect. However, the deviations in the frequency response of the Bryston 7B SST2 appear to be inaudible in normal high fidelity use, including the frequency response into the simulated speaker load. It seems to be well within the ABX Matching Requirements:
http://djcarlst.provide.net/abx_crit.htm
John Atkinson wrote:
"The Bryston's output impedance was low for a balanced design, at 0.11 ohm at low and middle frequencies, rising slightly to 0.17 ohm at 20kHz. As a result, the modification of the amplifier's frequency response due to the Ohm's Law interaction between its source impedance and that of the speaker will be small. With our simulated loudspeaker, the variations in response remained within ±0.1dB limits (fig.1, gray trace). The amplifier's response into 8 ohms didn't reach –3dB until almost 200kHz (fig.1, blue), which correlates with the well-defined 10kHz squarewave response (fig.2). The 7B SST2's output does start to fall slightly above 10kHz into lower impedances; into 2 ohms (fig.1, red), the output at 20kHz is down 0.4dB, though this will have no subjective consequences."
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"A fool and his money are soon parted." --- Thomas Tusser
I saw no perfection in the amplifier measured by JA. One can not conclude from measurements that a piece of gear sounds good. One has to listen to a system containing the device in question. One is still at risk of reaching the wrong conclusions as to the cause of what one heard. The measurements were far from perfect, as JA's equipment was showed.
If you want to convince me by measurements that an amplifier is transparent then I will have to be able to pick the source material. I will conduct a null test, comparing the actual output vs. the "correct" output. If the null tests shows that the error was -160 dB below the correct output measured with a 200 kHz bandwidth, then I might be convinced by measurements. (You will be responsible for providing the accurate test equipment. It might be available from the appropriate sources. I suggest going to the experimental physcists at CERN. They might be able to help you. I am talking far beyond Audio Precision. Test equipment needs to be 10x better than the device under test, and this is difficult with audio, where high end equipment is already at the state of the art.)
In the absence, I will just go with my ears. Why am I right and you are wrong? Because we are talking about audio amplifiers intended for listening to music, not laboratory instruments intended for conducting measurements.
As to perfection: "God made the integers, all else is the work of man."
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Did anyone tell you not to buy the amplifier you prefer? Certainly not me. In fact, I suggest people buy the equipment they prefer.
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"A fool and his money are soon parted." --- Thomas Tusser
Do you, by any chance, print your suggestions on toilet paper, too? Because that way, they could really be put to their intended use...
Because we are talking about audio amplifiers intended for listening to music, not laboratory instruments intended for conducting measurements.
You'll never convince the deaf who lack exposure to better gear and don't have the foggiest notion of what you're talking about. :)
Yes, I agree. Useless to try and convince the willful deaf.
One minor point of disagreement. One does not need exposure to better gear if one has access to the real reference. One can do this if one makes live recordings, or one can guess what one should be hearing if one listens to live acoustic musical performances. People who listen only to commercial studio recordings and amplified concerts can not possibly have a basis on which to judge sound quality. But then, does this matter? Today it's called "high end". It used to be called "high fidelity". Big difference between high price and high quality.
Maybe you will enjoy my recent post.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
One does not need exposure to better gear if one has access to the real reference.
That is my sonic goal as well. While I do regularly attend live concerts and enjoy listening to wifey play her baby grand, the majority of music I listen to is from commercial recordings. Having a ready reference of what any given recording can do provides a useful reference for comparisons.
I've been enjoying rediscovering my library following a recent preamplifier upgrade. I live to hear deeper into my favorite recordings.
Your linked story and background illustrates to me the only real way to compare various recording types. If Meyer and Moron compared live feeds at 16/44 vs 24/192 instead of using their Rube Goldberg approach, I suspect even they would have been convinced that Redbook is anything but "Perfect Sound". Over at AR, there's a Disney engineer who works largely with multi-channel soundtracks who likewise uses live feeds for determining recording quality all the way to up the DXD master.
The part in your story about having to really force the issue of worn cartridges with the subhumans was funny!
The sub humans are still around, but they tend to hang out on other audio forums.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
...I have listened to is the Bryston 4B-SST and I thought it sounded terrible - cold, dry and clinical but with excellent bass slam.
Real music does not sound like that.
"If it measures good, but sounds bad, you're measuring the wrong things."
How do you know that this wasn't what was recorded? The amplifier is just one component in a long chain from microphone to loudspeaker. Or perhaps your preferred amplifier interacted with the speakers and listening room in a more felicitous fashion.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
...listen to amps with more than one speaker which is the component that matters most with amps.And I listen to numerous recordings I am familiar with when evaluating a component.
Others report the same sonic signature with this amp.
Have you heard it?
Edits: 12/12/14
Accuracy to exactly what?
> Accurate amplifiers would be those that have flaws below known thresholds of hearing.>
Looking at the measurements he provided, I would guess that because the harmonic distortion is very low, he thinks the amp is accurate.
Obviously there is more to reproducing music than that...
sine waves - given that's how they're measured. :)
JA performs a number of different measurements on the Bryston 7B SST2, including a square wave measurement.
As for the inadequacy of using sine wave for measurements, you are whistling in the wind as far as I can tell.
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"A fool and his money are soon parted." --- Thomas Tusser
(nt)
E-stat complained about measurements made with sine waves, though without a shred of evidence that would invalidate the measurements. I pointed out the JA provides a square wave response, illustrated by his measurements for the Bryston 7B SST2, mentioned above.
So you think the 4B SST2 would not similarly have a good square wave response? That can be predicted by the FR measurements as JA remarked in his review of the 7B SST2. Look at Chart 1 from the Soundstage BHK Labs measurements of the 4B SST2: less than 2 dB down at 200 kHz.
I have never heard the alleged hardness of Bryston amplifiers. Many thousands who buy them seem to like them. Now, if you or Michael Fremer showed you could detect the hardness in controlled DBTs, that would give some credibility to your claim. That's one reason I don't give subjective reviewers much credibility when they talk about the sound of accurate electronics.
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"A fool and his money are soon parted." --- Thomas Tusser
...if two independent audiophiles whose ears I respect describe the same sonic signature to an amplifier that I hear, then it is an accurate assessment.
If you can't hear it, I'm not surprised.
In my own experience, I find DBTs to be pseudoscientific and worthless with audio equipment but scientifically valid for the new drug clinical trials in which I've participated.
You can use any method you like to select your equipment as long as you don't proselytize about it to the rest of us.
For some, ignorance of the truth is bliss.
"You can use any method you like to select your equipment as long as you don't proselytize about it to the rest of us."
Oh, I see! You can proselytize but I can't. Subjectivists can say anything they like, but it's not fair to be skeptical. Sure, sure.
On the other hand, you seem to think I proselytize about how to select equipment. How do I do that? I suggest people buy equipment they like. How is that proselytizing?
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"A fool and his money are soon parted." --- Thomas Tusser
Simple, you would think. Okay, since we know that there will be no converts, why can't everyone retreat to their respective corners, leer at reach other and go on with their own business...and perhaps, even enjoy music?
JA performs a number of different measurements on the Bryston 7B SST2, including a square wave measurement.
Yeah, that tells us absolutely everything about the performance envelope, doesn't it? LOL! It does, however, rule out switching amps since you always see considerable "fuzz" on their plots.
As for the inadequacy of using sine wave for measurements, you are whistling in the wind as far as I can tell.
And we already know you can't *tell* very far. I really don't understand such a persistent reliance upon such sketchy and incomplete metrics. At the expense of confusing the issue with facts, let's revisit what JA says about the "scope" of measurements with the review of the Ayre KX-R Twenty line stage:
All of the first-order sonic attributes—frequency balance, linearity, lack of coloration, etc.—are beyond reproach, which means one needs to focus on such higher-order qualities as the presentation of the soundstage and the accuracy of the imaging, neither of which can be measured.
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