Originally from the above suggestions, i understood you can get a Chinese crappy unbranded HU and use a sound processor to produce awesome hifi sound...
So, in reality if the source is not clean, a sound processor will just clean out the unclean sound and nip and tuck the bad signals and reproduce it with a flat response??? Which would actually mean that parts of the detail are lost??? Im getting lost here....
So for me, if I have a basic HU, like a Pioneer entry level with a 1bit DAC, the signals to the DSP ADC would be broken up and cleaned and flatizised and then recompiled by the 24bit DAC of the DSP (for the case of H701). But as the weakest link, shouldnt the 1bit DAC (from the HU) downgrade my overall sound compared to a HU with a 24bit DAC??? As per my previous knowledge, I understand the source has to provide the best sound quality (without tuning ie. TA and EQ) to a DSP to get the best sound quality with tuning for the car environment. A DSP would only be delivering optimized sound in stereo with some signal refinement in quality based on the quality of the HU.