Question about CD AUX and USB quality on my car head unit?

ok i was wondering which one had the best sound quality



an im mostly wondering If the USB input or CDS are better quality



beacuse on my head unit specs it says that the usb uses a

24 bit D/A converter



and CD's are only 16 bit



so wouldn't that mean the USB input is capable of higher quality?



here is a link to my receiver if you want to look at it

http://www.pioneerelectronics.com/PUSA/Products/CarAudioVideo/Source/CD-Players/DEH-P6900UB?tab=A



Question about CD AUX and USB quality on my car head unit?
Any time you have the opportunity to convert to an analog signal your sound will be better because that is closer to the natural wave form. Example for high end home stereo is to have a player go to a D/A converter then to an analog amp before the speaker. Now, to be honest, only 5% of the people will tell the difference in a quiet home environment in the home system, so in a loud vehicle most likely you never will see the difference if you could flip back and forth between the inputs. I would do whatever is easier.