Tuesday, February 28, 2012

Another proposal in the pursuit of affordable "high end" audio

Rev A - See notes

It seems to me that if Sony really wants to popularize SACD, they should offer inexpensive SACD DACs with the potential to demonstrate the format's potential for great sound quality, and inexpensive SACD players that could be used as transports in conjunction with these DACs.

The reason for having a separate DAC would be to ensure that the DAC isn't affected by the transport's vibrations and its demands on the power supply, the latter of which I've recently learned can cause audible effects if the supplies aren't adequately isolated from each other. [1] (I'm not entirely convinced that vibrations cause a significant effect, although I can't rule it out.) If the DAC and transport share a common enclosure, it's hard for consumers to be certain that these issues have been addressed.

These inexpensive DACs would be designed to have excellent, but not cutting-edge stereo sound, so that audiophiles would aspire to more expensive gear with better sound and more channels and features. If it threatened to stifle demand for pricey gear, it wouldn't be put into production.

Such a DAC could probably be made at a very low cost, considering that all that's required for direct DSD-analog conversion is a special, inexpensive analog filter. [2] This would allow audiophiles to spend more of their audio budget on recordings, and to wait until the economy recovers, or more likely, to win the lottery, before getting better gear.

Another likely reason such a device isn't available is Sony's concern with minimizing access to the master-quality digital content of SACDs. However, it seems that Sony could reduce the key components to a sealed module so that the decryption circuitry would be destroyed in an attempt to access its output. Furthermore, if greater efforts were put into making pirates worry more, Sony could worry less about letting us have such a DAC.

Rev A: Corrected and clarified explanation of DSD in note 2, and deleted "consumers" after "ensure" in 2nd paragraph.
[1] Optical disc treatments evidently improve sound quality in cheap players, not by reducing errors at the output of the error-correction system (which are essentially zero despite rumors to the contrary spread by audio hucksters), but by reducing the amount of work the servos must perform to keep the laser on track.  This in turn reduces their effects on the servo power supplies. In cheap players, the servo power supplies aren't sufficiently isolated from the audio section's power supplies, so that servo-supply fluctuations caused by servo demands are passed to the analog section's power supplies, and they affect the output signal.  So, in cheap players, disc treatments improve sound by reducing fluctuations in the audio section's power supplies.  In well-designed players, they have no effect, other than the placebo effect.

[2] DSD is a digital waveform modulated with an analog technique.  The continuous analog information is contained in the relative density of ones and zeros, and it is extracted with a special but inexpensive analog filter.