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Compilation of blind test reports
krabapple
post Jan 23 2012, 05:14
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I was wowed when I came across this -- someone went to a lot of trouble to compile most of the print and online audio equipment DBTs since the 90's

first post here:
http://www.head-fi.org/t/486598/testing-au...laims-and-myths

btw pretty sure he's wrong about Meyer & Moran only using CD-sourced SACDs, but I'll correct him on that ;



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mzil
post Feb 15 2012, 23:06
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Agreed, Krabapple, but if doing it again I'd say they should specifically limit their selections to one of "those" magazines "top ten best SACDs we've ever heard" sorts of lists. They have such lists, yes? [I don't read them so I wouldn't know.]
---

I can just see this will be the test doubters' next lame excuse: "Well none of those SACDs M&M chose in Test 2 have a crash cymbal or solo jingling car keys, so there's no appreciable acoustical power above 22.5kHz anyways..." [Not to mention there are only a handful of mics that pick up such frequencies, and they aren't typically used in studio work, I'm guessing. But I'm not a studio mic expert.]

...and then when they fix that in Test 3 we'll get: "But the speakers they used have poor polar response curves* (off axis dispersion) in the 30kHz range so other than on axis output, they were hardly energizing the room with key frequencies that make SACD sound so much better.."

See, none of these things are limitations when they tout how much better SACD is to CD; it's only when M&M run tests that don't support their beliefs that it's an issue! There's no end to it.

* I guess they use waterfall plots for this these days, but same thing.

This post has been edited by mzil: Feb 15 2012, 23:11
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Arnold B. Kruege...
post Feb 19 2012, 13:51
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QUOTE (mzil @ Feb 15 2012, 17:06) *
I can just see this will be the test doubters' next lame excuse: "Well none of those SACDs M&M chose in Test 2 have a crash cymbal or solo jingling car keys, so there's no appreciable acoustical power above 22.5kHz anyways..." [Not to mention there are only a handful of mics that pick up such frequencies, and they aren't typically used in studio work, I'm guessing. But I'm not a studio mic expert.]

...and then when they fix that in Test 3 we'll get: "But the speakers they used have poor polar response curves* (off axis dispersion) in the 30kHz range so other than on axis output, they were hardly energizing the room with key frequencies that make SACD sound so much better.."

See, none of these things are limitations when they tout how much better SACD is to CD; it's only when M&M run tests that don't support their beliefs that it's an issue! There's no end to it.


It might be good to anticipate as much of this as possible in the next round of proper listening evaluationss.

To clarify, your typical crash cymbal has its peaks in its power response well below 20 KHz, and usually even below 10 KHz.

You are precisely right about the general run of studio mics lacking response > 20 Khz, and they are even worse if not perfectly aligned and close to the sound sources. Ditto for speakers.
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mzil
post Feb 19 2012, 18:30
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QUOTE (Arnold B. Krueger @ Feb 19 2012, 07:51) *
To clarify, your typical crash cymbal has its peaks in its power response well below 20 KHz, and usually even below 10 KHz.


I understand your point regarding masking, in the earlier post, which I agree with, however it is my understanding that spectrographs of the crash cymbal show it has the strongest power output (40%) in the > 20KHz range (not peaks, but rather everything) , at least compared to any other acoustic, conventional musical instrument I've ever seen measured, even more so than the musical triangle. [Which I had previously thought would have had a lot of content up there, but I was wrong. It is only 1%.]. That's the only reason why I mentioned it.

The best case trumpet's >20 KHz power output is a measly 2%, by comparison, in the study I link to below, but that may be a candidate as well.

The only things even higher in power output (up there) aren't conventional acoustic instruments, such as jangling car keys (68%), which I mentioned, other similar sound effects/noises, and electrically generated wideband noise or other test tones, I suppose, specifically generated for one's test.

I don't think there is such a thing as a conventional instrument with strong > 23KHz content that doesn't also have the strong (masking) content in the nearby, lower (actually audible to some young people) octave(s) which you are correct to warn about. However, I don't see M&M's detractors bringing that up as an argument though, since it then puts the ball in their court to name a qualifying example that would work, yet not have the same masking problem you speak of, and they can't. It simply doesn't exist on any conventional, music SACD, I suspect.

QUOTE
Instruments Without Harmonics....
...
Fig. Instrument................... SPL............ 10 dB Above.........Percentage
.........................................(dB).............Bkgnd. to.............of Power
............................................................What Freq.?..........Above 20 kHz

10. Speech Sibilant..............72. ............>40 kHz ..............1.7
11. Claves.........................104. ...........>102 " .................3.8
12. Rimshot........................73. ............>90 " ...................6.
13. Crash Cymbal...............108. ...........>102 " ................40.
14. Triangle.........................96. ...........>90 " ...................1.
15. Keys jangling..................71. ...........>60 " .................68.
16. Piano...........................111. ...........>70 " ...................0.02
-

Source:
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

This post has been edited by mzil: Feb 19 2012, 19:11
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