SACD Downconverted? What good is that!

[Big C]

If the purpase of SACD is to experience 2.8-MHz, 1-bit, high-resolution DSD audio quality, why do many manufacturers' DVD players downconvert it to lower sampling rates/resolutions that use a PCM-type audio stream? Doesn't this aproach totally ignore the whole point of SACD?

[Aargonaut]

The 2.8 million samples per second used by SACD is a marketing gimic. There is no audible difference between an SACD played with DSD and one wich uses a downconversion to a 192K/24 bit sample. Very few amps produce much above 20K cycles per second, let alone out to 100K cycles you get with DVD-A at 192K. (My Harman Kardon Citation amp is -3 db at 170K.) Even at a 96K sample, you will hear virtually no difference between DSD processing and downconversion.

You might get 2.8 million samples per second with SACD, but you also get a one bit word. The digital noise produced by the one bit sampling technique used with SACD is actually a huge distortion. (SACD's dirty little secret.) There is a web page out there which shows how SACD and a DVD-A play back a 20K square wave. The DVD-A is much cleaner. The SACD has some blurring. SACD using DSD uses filters to cancel the digitization noise caused by a 1 bit word. Similarly, 192K PCM filters out the "missing" data by the sheer number of samples.