What’s going on over at Computer Audiophile? I know many of you are active readers of my site and Chris’ CA site. I try to stop by there every so often and see what’s brewing. In general, I’ve found the heat a little high for my sensibilities…and some of the “facts” expressed are more personal opinion than bona fide information. But what could possible prompt the CA community to post 530 comments on my assertion that 96 kHz/24-bit PCM surpasses DSD 64? A sophomore member of CA titled his thread “Mark Waldrep is claiming that PCM 24/96 is superior to DSD” and then went on to copy my entire post from April 11, 2105…the one that took issue with Sound Liaison for upcharging its customers for DSD version of their source 96/24 PCM recordings.
He asks a simple question, “Mark Waldrep is claiming that PCM 24/96 is THE format and that DSD should be cheaper than PCM. Comments? Is he right or just promoting his Itraxx pcm recordings?”
The simple answer is yes, if you consider the technical specifications between the two formats (never mind that you can’t actually produce most recordings in DSD because of the lack of tools). PCM recordings made at 96 kHz/24-bits have greater frequency response and dynamic range than DSD 64 tracks. The noise shaping required to increase the dynamic range beyond 6 dB (the result of 1-bit encoding) in the “audio band” is deposited just above the top of our hearing range. Look at the spectra of a typical DSD 64 track below:
Figure 1 – A spectrograph of an “audiophile” DSD 64 recording. [Click to enlarge]
The purple “haze” in the high frequency area of the left hand spectral displays are the ultrasonic noise…put there by the noise shifting. It’s supposed to be out of the “audio band” but there is no “audio band” for your playback equipment. Imagine how your electronics and tweeters feel when this type of recording comes along…all analog sounding and warm. You bet. The graph on the right is a big side letter “V”. At a point just above 23 kHz, the line steadily rises almost back to where it started. Welcome to DSD 64. Any resemblance to high-end audio is purely coincidental.
What about dynamic range? DSD can actually eclipse a CD in dynamics AFTER the noise is plowed out of the way. But it doesn’t come close to the theoretical 144 dB that 24-bit PCM can achieve. Those specs are great for recording engineers like me but the fidelity of your system will never benefit from 24-bit DACs or fidelity. There simply are no recordings being released that have that much dynamics and your room couldn’t handle it if they were.
The answer to the question posed back in April at CA is quite straightforward. How is it possible for Chris’ reader to spin out 530 comments arguing about a true statement? I haven’t read all of the comments. The ones that I did read focus on the personal preferences of readers for the “warmth and analog sound” erroneously attributed to the DSD format (remember the study that determined that no one could tell the difference between mics split to a PCM rig AND a DSD rig).
I guess We should all feel pretty good about this blog site…I couldn’t make it through the approval process for 530 comments! Thank you for understanding the basics.
Have a nice Saturday evening…Charlie’s excited because our daughter is coming home today.