By using the additional processing power to overcome speaker and environment shortcommings.
From my experience, in a SQ system the "perfect quality" aspect is broken down like so:
Speakers and their installation = 90%
Source unit = 6%
Amps (run within their acceptable limits) = 4%
Now because cars are such a PITA to work with getting your speakers upto the "full" 90% value is damn hard, thus being able to throw some very complex signal processing can have significant advantages.
For example a 128kbs Mp3 will sound naff compared to a CD (generally)
whereas a FLAC file in theory should be the same.
If you can get a reasonable sound card (X-Fi series are good) the sound should easily bypass the average head unit.
I agree that the speakers are generally the most important part of the installation but with a carpc introducing MP3, wma, aac etc you are reducing sound quality before it had even made it to the sound card and you can't polish a turd
I agree it's high. But it's high as one has to do some prety stupid things to make a bad sounding CD player or amplifier. Solid reference designs for CD players and amps have been out in the market for many years. Where as speaker designs that have less than 5% total harmonic distortion at listening level, and 10% THD at max volume are near impossible to come by.
Understand that while I like the audio quality of my system, it is far from award-winning.
The people that I know that compete in SQ competition have invested many times what I have invested in audio hardware....
Have you looked in the FAQ yet?
How about the Wiki?
Under normal circumstances, a signature would go here.
Like it was said depends on the components that are used. RedGtiVR6 is a great example here She has won 3 world Championships in USACi using a P.C. but she uses grade A product.
She also uses a Alpine 701 unit just like i do. But i have seen the audio card that she is modifing big time and I am VERY interested to read about it once its finished. That will be a 100 percent PC audio ran system. No processors no in line amps to the system. That would be very cool and a TON of control.