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

Showing 1 response by plato

I always thought that some of the SACDs that I've heard did not sound natural in the high frequencies. The above disclosure in Stereophile may explain why. I never bought into the format and now I'm glad I waited. With upsampling, I get decent performance out of many Redbook CDs and of course, vinyl is my refuge.

Curiously, I find the high frequencies on many DVD-V movies to be quite natural and pleasing. Maybe they should dump SACD and DVD-A and explore what can be done with the standard DVD-V format.

I can't help but be discouraged with the state of digital recording. Most of the young folks I know think that MP3 is just fine and are building large libraries of music in that format. I tell them that MP3s sound bad on good equipment and they couldn't care less -- looking at me like I'm from Mars or something. They know very little about SACD or DVD-A (and these kids are among the more informed and technically savvy young adults I know). It is really scary to think that the easy distribution of MP3 files via the Internet could elevate that format to the future medium of choice.

One 20-year-old told me today that they are coming out with computer hard drives for the car with writable CD-ROM drives for saving music files (in MP3) from the digital tuner. He said such a unit costs about $1500 now, but that prices should drop as these units become more common. He was so excited.

My apologies for having strayed from the topic.