Originally Posted by liel
Just got my new car Mercedes c300 coupe with Burmester surround system.
Is there a difference between Aux, Bluetooth or Apple CarPlay (With USB) in terms of audio quality?
I have BMW's but the concept is the same.
I would disagree with the bloggers comment on AUX though. Quality will depend on the best DAC. If the head unit has the best DAC, USB will have the best connection and likely better than your phone's DAC, which isn't used as the stream is digital. So USB is best unless you add an external DAC to the chain.
I sometimes use a portable DAC, a Oppo HA-2SE, and connect the iPhone lightning cable to USB in on the DAC and the DAC's 3.5mm line out to the cars AUX in. This gives me the best quality playback in my tests, until I get on the road and then I can't tell the difference.
I lose convienience in that mode, no steering wheel control, no album art, etc. so seldom take the trouble.
I am upgrading my sound system though and may add an optional HELIX Extension Card HEC AUDIOSTAGE to my Helix DSP when it is released. It adds an HD-Audio WiFi Interface, has a USB port, IOS and Android apps, supports High Resolution Audio, FLAC and ALAC, has a Spotify connect client etc. while by-passing the head unit.
Not sure I will go through the trouble but I've blown all other rational thinking and budget out the window and am ending up with a fantastic aftermarket solution.