Can I adjust treble/bass level on Garmin c550 mp3 player?

I haven't found any separate bass/treble settings.
FM transmitter won't provide a clean signal especially in a populated area or where there isn't much separation between the fm frequencies.
Some people say the cassette type transmitters work better, not sure if that's an option for you. You could possibly try a higher bit rate when converting to mp3. But, I really don't think that will help much, and it will take up more space.
I'm in a populated area and tried an fm transmitter, mp3 weren't horrible but not cd quality either.

If your vehicle's audio system is compatible, it will add a "line input" to the audio system. I have a wire in the glove box I pull out, and plug into the GPS' headphone port - and it works like a charm - MP3s play and sound great, and Karen interrupts the music when I've done something to annoy her.

Pun intended!

Thanks keith

So with this system/set-up, your mp3's sound on par w/cd quality? No static, interference? Any cons?

If not, I think I'm going to order one.

Thanks again.

The MP3s sound good to me - no static, etc. and I've not found any cons, other than I need to get some more CDs ripped to MP3.

Thanks again

After looking at their website, it looks like it's possible to still use your vehicle radio/cd player and have the gps voice come through, if not using the system for the gps/mp3 play. Maybe I'll try contacting them to see if what I interpreted was correct.