USB adapter vs. DIN AUX input sound quality

[Richbot]

My car does not have the USB adapter for iPods and whatnot, and I just use the aux jack with a male-male cable to listen to the iPod in the car. The sound quality seems less than ideal. Is there a significant difference between the sound quality you get when running an iPod through a USB adapter as opposed to the DIN aux cable?

I know it's possible to have a stealer retrofit the factory USB adapter, so it might be worth it. Sound quality through my base system is just fine using CD's or the radio, but it leaves a lot on the table when I'm using the iPod. Our 335 with the USB adapter doesn't seem to have this issue.

[WillC310]

I think the USB portion is just to control the iPod, not play music. The iPod adapter connects to both the USB and AUX in. I could be wrong since I haven't tried it out yet though.

[ducman]

I'm not sure why the ipod adapter connects to both the usb and aux since I don't have an ipod (though anyone knows why?).

But since my blackberry comes with a usb adapter (no aux), I use that to connect to the usb port of the car and the music appears in the 'external devices' and they play fine.

[JCtx]

I use a flash USB drive for my music, which obviously uses the USB port alone. Has CD-quality sound, and can control it like an iPod, and shows artist, song, album, etc. From past experience those aux inputs don't sound nearly as good, so USB is obviously better. But have no idea why the heck you need that little aux input for the iPod .

[808MGuy]

It is true that when using the ipod with the OEM ipod adapter you use both the USB and the aux input. The USB is only used for control and ID3 tag data and the aux is used for the sound. Not sure why they did it like that but that's the way it works. If you plug in the USB and leave the aux unplugged you get no sound from the ipod. I use a USB flash drive as well. By using the USB flash drive, you get the convenience of controlling from iDrive like the ipod without having the suffer from the crappy D/A converters in the ipod. You get direct digital transfer from the USB drive to the iDrive which makes it sound a whole lot better provided you're using high bitrate encoding like at least 256kbps CBR or 224kbps VBR.