A DAC and a DSP chip perform two different functions (generally). The DAC is what converts a digital bitstream to analog. A DSP chip is what does the calculations on a digital signal to do things like room simulations, bass management, EQ, mixing and other functions. A DAC chip is not supposed to change the signal in any way, but to just convert it from digital to analog as cleanly and accurately as possible. A DSP chip is used as the compuational engine to change the signal in some way. Having more than one DSP allows more complex calculations to be made in real time, such as more realistic reverb fields and more EQ bands to be made. In this sense it is no different than having more than one processor in your PC to do number curnching.

Chips that do things like Dolby Digital and DTS decoding are hybrids that use DSP engines to decode the digital bitstream and DACs to output the result as analog (a very rough expalation). Chips like the Cirrus logic would do their soundfield enhancements by DSP processing.

None of this is really in the control of the buyer except in the sense of more expensive equipment generally having more computational horsepower available to process a signal. However, the mere presense of more DSP power does not guarantee that the programming that those DSPs are carrying out is necessairly as good as a less expensive unit that may have better programming built in to take better advantage of more limited computational power.

This is just like in the PC area - some programs are better than others at doing the same task, and some are more efficient than others.

[This message has been edited by soundhound (edited April 04, 2004).]