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A Possible Reason for SACD to be Superior

I have recently been trying to compare the SACD format to Redbook on my system and have discovered that the SACD layer on the disk seems to always be recorded at a lower volume making an A/B comparison extremely difficult because while switching layers on the disk isn't too difficult, matching relative volumes is and comparing the sounds at the same volumes is key to any comparison.

What I did realize, however, is that this means that the SACD signal isn't as attenuated (is that the right word?) as much by the preamp to obtain the same volume. Shouldn't this be preferred? If I understand my EE friend correctly, and I often misunderstand him, the ideal situation is for the signal to pass through the preamp without attenuation which means 0 db on a piece of equipment that give volume readings in -dB. From this perspective it seems that SACD should have the advantage.
mceljo
isochronism
2,893 posts
 
Schipo, I believe Jmcgrogan's comment is facetiously pertaining to Mceljo's recent post asking why high priced aftermarket PC's. A good one, John! :)
aplhifi
515 posts
 
I have recently been trying to compare the SACD format to Redbook on my system and have discovered that the SACD layer on the disk seems to always be recorded at a lower volume making an A/B comparison extremely difficult because while switching layers on the disk isn't too difficult, matching relative volumes is and comparing the sounds at the same volumes is key to any comparison.

SACD playback usually results in 6dB lower output level, compared to CD at 0dBFS. This is the reason why most SACD players use digital attenuation for CD playback in order to "level" the two formats, which essentially compromises CD audio quality.

If your SACD player does not correct this, you are lucky. :-)
So just measure and adjust playback volume to +6dB for SACD and you're done.

Of course, the level difference will vary depending on the recording level at which the CD and/or SACD were mastered. But in the case for double-layered SACD hybrids, the 6dB has to work.

Best wishes,
Alex Peychev
mceljo OP
1,357 posts
 
Jmcgrogan2 - Touché. I keep thinking that I should apply the theory that the best cable is no cable at all, but for some reason that doesn't seem right either...I did actually do this with the subwoofer in my home theater rig, but my wireless printer stopped working.

Aplhifi - Great information, thanks. I'll have to see if my Sony blu-ray player, that handles SACD, make this correction or not. I suspect that it does. My Pioneer Elite SACD player definately does not.

Going back to part of my original question, if two recordings were identical with the exception of the output level, would it be expected that the one with the lower output would sound better when played at an equal volume?
kijanki's avatar
kijanki
4,432 posts
 
In spite of different output levels source material could be recorded with the same compression. It is difficult to compare CD to SACD since they are completely different but just looking at the bit rate coming out of both we can judge about quality. CD output rate is 1.4MHz while SACD output at 5.6MHz. In addition, because of very nature of Sigma-Delta converters antialias filters in front of the converter are set to much higher frequency allowing recordings with better pulse response. It also shows in extended bandwidth (50kHz vs. 20kHz). SACD output stream is very similar to amplifiers class D operation (Pulse Width Modulation) and needs very simple converter to make average values. Quantization noise is moved up to non-audible band. Overall dynamic range is higher(105dB vs 96dB).
mceljo OP
1,357 posts
 
Kijanki - So why do you think it is that something like SACD, that from a technical aspect should be superior like other high resolution formats are considered to be, doesn't seem to be supported much in the audiophile world? Neither of the audio store locally do anything with SACD.
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