very specifically for dts, dolby digital, etc. ONLY what would one want better dsp or dac... from what you are saying the dsp does the processing and the dacs just convert its (dsp) processing into analog. which is what i know as well, and seeing as the dsp is upstream (so to speak) of the dacs, the dacs would be limited on how good the dsp would be. if the dsp is not doing a good job then the dacs never will, but if the dsp is doing a good job then and only then can the dacs make a difference. that is pretty much what i thought...
however its curious that a lot of companies employ 2 or more dsp chips while hardly any employ more than one dac per channel. well i guess it is not so curious if the dacs are important, but the products that you find 2 dacs on a channel are top of the lines.
if you look at two solid audio companies, yamaha and denon, yamaha's focus is on dsp processing and denon's focus is on dacs. and while i know that both are USED IN COMBINATION and one does not make a product superior, yamaha emphasizes dsp (they even use their own!) and denon has 16 dacs in differential configuration which you dont find except in levinson gear (or its likes).
i always thought dsp processors were for sound fields and not dolby digital, dts, etc. but they are not, and eventhough dolby doesnt require quite as much processing (just reading and routing) as simulated fields, i suppose they are more crucial (strictly speaking) that dacs.