This post continues my discussion of the “One” music project from PS Audio. I regard the project a highly laudable effort to bring well-recorded music to the audiophile marketplace and assist the musicians, producers, and engineers. However, it was recorded using a Sony DSD 64 Sonoma system, a very old and outdated recording platform. The files I paid $35 dollars for were upconversions of those original DSD 64 files to 176.4 kHz PCM files. I talked about file conversions previously…there’s no benefit to the end user. The fidelity of the original file doesn’t benefit from being jacked up to 176.4 kHz and 24-bit words in the PCM format. My criticism is centered on the myth that selling a 176.4 kHz file added to the fidelity of the original master. It doesn’t. But the end user gets charged for a bigger file, has to download a bigger file, and has to store a bigger file. My recommendation would be to downconvert the album to 48 kHz/16-bits…the fidelity will be the same and you’ll save a bunch of memory.
Paul writes “just because the noise floor is rising doesn’t mean the signal level is falling”. He’s right. But the rising noise obliterates any possibility that those high frequencies will ever be heard. The effect is called “masking” and it’s a very common phenomenon. Think of a wave machine generating the soothing sounds of the ocean to block out obnoxious sounds that might keep you awake. If there are any high frequency components to be heard in these tunes, the DSD induced noise “masks” them completely. When the advocates of DSD 64 and SACD claim a frequency response of 100 kHz, they usually forget to mention that it comes with 6 dB of dynamic range. Thus the reason for the noise shift.
Figure 1 – The rising red line “masks” any high frequencies that are present in the source DSD recording.
The level of high frequency noise IS a real problem for real systems. Manufacturers have two choices in dealing with excessive high-frequency noise that happens with DSD. One option is to roll it off using a filter (either analog to digital during the playback). This begs the question; Why would anyone want to download a file full of stuff that’s ultimately going to be rolled off later? The noise and 176.4 kHz sampling rate doesn’t contribute anything to the fidelity of the music…so why bother using that very high sampling rate? The second option is to pass the entire signal to the reproduction system — including the ultrasonics — and let the chips fall where they may…obviously, this is not a viable option. Our ears may not hear the ultrasonics but the equipment will.
The next question is, “could his systems take higher levels of signal in the upper frequencies than DSD uses? Paul assumes no but in fact, the answer is yes. PCM at 96 kHz does offer an additional octave of ultrasonics before the reconstruction filters begin to remove any information. Frequencies that are not “masked” and might have a role to play in the enhanced sound of high-resolution music. The use of 96 kHz does contribute to the sound because of gentler filters and moving the pre and post-ringing to near 48 kHz.
The argument over which format is best is actually pointless. The world is dominated by PCM and will remain that way for the rest of my lifetime and probably far beyond. My point in providing the spectra in the previous article was to show that downloading a very large file that contains a significant percentage of noise makes no sense (other than to brag about a 176.4 kHz sampling rate). Just give me that part of the file that contains music and forget about including the noise.
I think the “One” recordings are excellent and I enjoyed most of the tunes. My criticism is about the use of 176.4 kHz to deliver fidelity that would have identical at 48 kHz. Don’t fall for the DSD hype…it’s not “warmer” or “more like analog”.
PS I received a number of private emails that told me to forget about spectra and left brain technical analysis of music. All that matters to many audiophiles is the richness of the playback…if that’s enough for them, great. It’s not enough for me.