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Stereophile "confirms" Moncrieff's SACD comments ?

You folks remember a thread about SACD that mentioned J. Peter Moncrieff's comments about SACD being "junky" at higher frequencies ? Well, if you read the September issue of Stereophile's review of the $16,500 Accuphase SACD player, you will see that John Atkinson somewhat confirms Moncrieff's statements. Here is a direct excerpt from the test results that JA published in that specific Stereophile review ( pages 115-116 ):

"Again, the player's excellent dynamic range is revealed, at least in the low treble and below. Note, however, the rise in the noise floor above 2 KHz, this due to the aggressive noise-shaping used by the SACD's DSD encoding. By comparing fig 4 with fig 3, you can see that SACD has less inherit dynamic range above 10 KHz than CD, though this is largely academic, i feel."

Since you can't see the graphs without looking at the actual magazine, i'll try to sum it up. CD shows a rise in noise above appr 2 - 3 KHz. The slope climbs at a gradual rate as frequency rises. On the other hand, SACD shows the same rise in noise at about the same frequency point, but the slope is much faster and sharper. By the time we get to 20 KHz, standard "redbook" CD is actually about 15 db's quieter in terms of the noise floor and increased dynamic range.

Besides all of the above, which some "might" say justifies Moncrieff's opinions of poorer high frequency performance on SACD, JA goes on to show the spectral analysis well beyond the 20 KHz range. The rising noise level that begins at about 2 - 3 KHz continues to rise until we hit appr 70 KHz. Using a dithered 1 KHz tone as a reference, the noise level climbs to a point that is PHENOMENALLY high i.e. appr 80+ dB's noisier than it is at 1 KHz !!!

While i don't know if this phenomena is directly related to the Accuphase design being used or can be found in all SACD players due to the wave-shaping taking place, it makes me wonder if this is what has given me a headache aka "listening fatigue" on a few occasions when listening to some SACD's ??? Is it possible that the level of ultrasonic noise and ringing is high enough to the point that it can ruin what might otherwise be a pleasureable experience ?

As a side note, the jitter on this machine is PHENOMENALLY high. JA measures it at 4.26 nanoseconds of peak to peak jitter while running in redbook format. He comments that this is "more than 20 times higher than i have found in the best cd players and processors". He then goes on to "feed a signal into the DAC section of the player via the DP-85's S/PDIF data input with 16 bit data of the same signal, the measured jitter level dropped to a respectable 311 picoseconds." As such, the phenomenally high level of jitter is directly related to how they are transferring signal from the transport into the DAC. For a "lowly" $16.5K, you would think that they might be able to do a little better. Even the "respectable" 331 picoseconds of jitter is quite high in my opinion. Sean
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sean
pardales
652 posts
 
After experimenting with SACD via a Sony 333 changer I have decided to maximize my extensive redbook collection. I have the new Mcintosh changer which sounds great and is utterly non-fatiguing, and I am going to audition an MSB Platinum Plus and a few other DAC's just to see if they make dramatic improvements. There are tons of redbook CD's out there and SACD just does not have enough titles I want at reasonable prices.

I can't speak to the numbers discussed earlier in the thread, but SACD is just nor practical for me. Good thread, thanks,
clueless
763 posts
 
Sean, maybe JA needs to upgrade his cables. I'd recommend the new the "Zeus Jitter-Litter 2002s” They use an advanced proprietary transmission-line method to redirect the incident and reflective waves caused by the jitter. It’s really straightforward. The wavelength of the JitterLitter mechanism is equal to the Square root of the frequency divided by the change in angular velocity divided by Pi:

λ= √f/∆ω /π

I’ve used this cable to keep my toaster from popping up prematurely for years.

Sincerely
I remain,
rcprince
3,059 posts
 
Tswhitsel: Nice to see another Audio Logic fan. Jerry's designs turn the pcm stream into DSD in the converter, which is why they sound as good as they do, in my view. Now imagine his analog stage, with a separate power supply, used in place of the Sony 777ES's analog stage for SACD, and you'll have what I've been enjoying for the past almost 2 years. A definite step past redbook, and I think Fremer's article on the Accuphase hits the differences between SACD and CD right on the head. I have not been bothered in the least by the distortion figures above 10Khz, which is well beyond anything I really listen for anyway (take a look at where the frequency range of instruments ends, you'll see what I'm talking about) and borders more on a theoretical rather than practical concern. I'm very happy with SACD, but I'm not a zealot; I could be equally happy with 24/96 DADs, as I have playback of that in my system as well. Unfortunately, Plato's early post is most telling. In my latest conversations with the estimable Mr. Ozment, he says most of the consulting work he's been getting these days has been for MP3 type products. He's not at all confident that the hi-rez formats will ultimately stick, which would be a shame but, hey, we're not the folks the music industry is listening to, we're a small minority. Hopefully the smaller specialist labels will stick with the format, and maybe the release of the Stones' catalog on SACD will act as a catalyst for the medium. In any event, I'll enjoy the fine recordings I've got on SACD, and keep putting the vinyl on the turntable for ultimate enjoyment.
bomarc
501 posts
 
Um, a one-bit system like DSD has a HUGE amount of noise that cannot be eliminated. That's why they use nosie-shaping--to move the noise into the ultrasonic range where (best evidence suggests) it won't matter. So all that noise is supposed to be there. It's inherent in the process.

That said, it's a little disconcerting to see a substantial amount of noise in the audible range as well. As Djjd says, it might not be audible. But it ought to give SACD fans pause.
jameswei
883 posts
 
JA's data suggests to me that good engineering design and layout remain paramount in high end players. A good format won't offset bad execution. We have seen LP playback equipment change and evolve for better sound (e.g., Graham, VPI). We have seen unanticipated redbook artifacts like jitter be discovered and designed away. It seems to me that the high frequency dynamic compression and noise may be artifacts inherent in DSD/SACD, and the big guys, i.e., Sony and Philips, may have addressed these issues (I,too, am happy with my SCD-1) while the smaller guys with lesser resources, i.e., Accuphase, may have either missed them or decided not to try to fix them. Notably, the fact that the Accuphase did not properly control jitter suggests that this product was not well thought out, perhaps developed hastily. While I agree that allowing such problems in a $16,500 machine is unforgivable, I expect a "new, improved" second generation offering shouldn't be too far behind.
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