Dynamic Comparison SACD vs CD - Part 5 - page 5
The SACD layer exhibits exactly the same brick wall at 20kHz but layered with the rising DSD ultrasonic noise from about 24kHz onwards:
Frequency analysis around 3:45 of Track 1 of SACD layer (recorded on soundcard)
I was fairly disappointed by the lack of ultrasonic frequency components on the SACD layer, as it indicates that the SACD may have been mastered from a low-resolution PCM source.
I checked the liner notes, and discovered the engineer (Jim Anderson) clearly can't quite remember what the original recording format was:
"What we did for these SACDs was to go back to using the analog masters exclusively."
"No… let me correct that. We used an older Mitsubishi 32-track digital machine on Café Blue, and now that I think of it, we didn't produce an analog master for Café Blue."
So it looks like my worst fears are confirmed - Café Blue originated from a low-resolution multi-track PCM recording.
Conclusions
First of all, regardless of whether Café Blue was originally recorded in analog or low-resolution PCM, it still doesn't change the observation that it is an excellent recording. Perhaps it is a useful reminder to us just how good 44.1kHz 16-bits can be, especially when all 16-bits are used and dynamic compression is avoided.
The differences between the CD-R of the original release and the remastered CD layer also highlight the benefits of careful remastering using the latest technology can bring even to digital recordings.
In that case, what accounts for the audible differences between the CD and SACD layers? I'll leave it up to the reader to draw his/her own conclusions, but here are some possible reasons:
- There are no differences between the CD and SACD layers. Any observable differences are purely a figment of the listener's imagination
- The differences are due to the relative accuracy of the player in reproducing PCM vs DSD.
- The differences are due to the CD layer clipping or exhibiting 0dBFS+ levels.
- The differences are due to the SACD revealing more of the benefits of the remaster that was possibly done using high resolution processing.
- The differences are due to the DSD ultrasonic noise somehow affecting the playback chain or our hearing.
- The differences are primarily due to the relative level difference between the layers (the SACD layer is on average around 0.7dB louder than the CD layer which would be just audible).
