Originally Posted by Bojamijams
While I appreciate the in-depth reply, I already have a car deck that I like. Currently I'm using an LOD out of my iphone into the AUX port of the car deck and am now looking to do the same setup with an Android device.
Everytime I've tried using a car stereo's DAC (which is what I'd have to do if I used a USB stick or connected the device to the car through USB), it was always sub-par. Maybe the DAC's in a luxury car are actually good but I found my iphone 4s' line-out to be superior to any car deck I've yet compared it to.
That's kind of strange; usually the analog output circuit would at least be better. On the other hand, as far as my set-ups go, time alignment worked a whole lot better than a better DAC. I once got to listen to a similar car with a Denon deck, which supposedly has the best stereo circuit (in a copper chassis to boot) but no processor, and no matter how musical it was, my time aligned set-up can go toe-to-toe on staging and imaging (not to mention my receiver was a fraction of the price). I even got to listen to one using only one of those V-Drive (high output) Alpine decks and cheap raw drivers from Taiwan, no amps and sub, and the soundstage was nothing you'd expect from $40 speakers (that's for the whole set), the time alignment and proper installation of the drivers making all the difference.
On the other hand, maybe the differences you noted is because of the choice of DACs. Given cars need several channels of analog output, even (especially?) the audiophile receivers that have pro-audio features (Nakamichi and Denon aren't really into the no processor receivers anymore, or car audio for the most part), they use the same DACs as on video disc players and surround processors, although for some applications the processor matters more for getting around the problems of a car's cabin.