Hmm. What about the DSP? Doesn't that fall after the DACs in the signal chain?

All of the processing the DSP performs (tone, equalization, loudness, etc.) comes immediately before the DAC. In the case of the Empeg (if I remember correctly) the DACs in the Empeg are actually contained within the DSP chip itself. Nevertheless, they are the final step in the process before the analog processing. In many other cases, the DACs are completely separate components.

As I understand it, some consumer devices use a similar (perhaps even the same) DSP to shape the sound.

You bet. There are quite a few DSPs out there to choose from, and quite a few processing steps they could perform. In particular, many portable players provide equalization, bass boost, loudness, spatialization, etc. I even used to have one that did dynamic range compression like rjlov's volume adjusting kernel.

Home players tend not to do extra signal processing, however, leaving that task up to the preamplifier/receiver. So all of their digital signal processing tends to be limited to interpolation and noise shaping (for oversampled systems only), and maybe DAC preemphasis.

Perhaps that's germane to this discussion? Maybe products which don't use DSPs have some sort of analog circuitry in the output stage which makes the music sound less strident?

Sure, that could very well be the case. All digital music devices have some analog circuitry in the output stage that will affect the sound quality.

But it's important not to try to pin the blame on any one stage in the signal processing chain. The conversion from digital data to output voltage is a long process with many steps, each of which can contribute in different ways to distort or color the sound. When comparing two CD players, you're comparing systems, not just DACs or DSPs alone.


Michael Grant
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