Is SACD really high resolution?

rwortman -- Sat, 02/13/2010 - 12:04

It seems to me that the reasoning I am reading confuses SN ratio with resolution. If you take a poor resolution system and push the noise out of the audio band, it reduces the effective noise but I don't see how it increases the resolution. To duplicate the true mathematical resolution of a 16/44 PCM recording (CD) with DSD it would seem to me you would have to produce a PWM pulse train with 2 to the 16'th power (65536) different possible widths at 44.1khz. This would require a sample rate of close to 2.9ghz. About 1000 times what is used for SACD. SACD would seem to have a true resolution at the upper end of the audio band equivalent to 6 bits at 44.1khz. I don't have many SACD's or DVD-A's and my Marantz universal player isn't the most expensive thing you can buy but in my limited sample the DVD-A's that I have made from 24/96 FLAC files from HDTracks sound better to me than the SACD's I have purchased. The SACD's sound wonderful from the bottom all the way through the upper mids but they have a slight bit of HF weirdness that reminds me of inner groove distortion. Maybe that's why the analogue aficionado's seem to like this format?

Tom Martin -- Sat, 02/13/2010 - 12:55

Others with more background in Delta-Sigma conversion will know more, but here are a few indicators that SACD might be able to do things that Red Book CD can't:

1. Raw information density is higher. SACD uses a 2.8 Mhz bitstream; Red Book operates on a 700kHz bitstream. In addition, the SACD bitstream uses lossless compression, the Red Book bitsteam is uncompressed.

2. Measured data. SACD systems can deliver 50kHz bandwidth and 120 s/n. By the Nyquist theorem, Red Book cannot exceed 22kHz bandwidth. 93 db is the base s/n for 16 bits, but noise shaping can push higher I believe. Converting the SACD data to PCM equivalent, SACD is like 20 bit, 96khz sampling PCM.

Most of our reviewers have found that often the discs you use to try SACD vary quite a bit. Many did not start as DSD. Some seem to have been EQ'd in a strange way. Therefore, it is hard to declare SACD as a system (from recording studio to your ears) hands down better than Red Book. Some players don't do SACD well, which adds to the confusion. Those issues are amplified when you compare SACD to other HD audio formats.

That said, most of our reviewers have found that SACD done well has a level of high frequency purity, combined with microdynamic depth, that can exceed red book CD.

CEO and Editorial Director, Nextscreen LLC

gerard french (not verified) -- Tue, 02/16/2010 - 08:16

Perhaps if you have no clear answer to the tecnical problems on s a c d you could try to listen to a recent d s d recording from channel classic on a high quality system for example the Bach sonatas and partitas interpreted by julia fisher

peter oshea (not verified) -- Mon, 02/15/2010 - 01:28

rwortman,

what software do you use create your dvd-A's?

Thanks,

Peter