MP3 player question. (Off topic)

A car is normally filled with electromagnetic interference sources, so you are bound to have more noise, especially considering that you cannot properly ground (bond rather) the MP3 player. One the other hand, you will hear no difference because of all the road noise. I constantly listen to MP3 in my car, hooked up exactly the way you asked about, and I have to deal with occasional cracks and pops, but that does not bother me while on the road.

You are right, it is way OT, but I would suggest that you toss this question to folks at sci.electronics.basics That crowd is extremely responsive and they would love to give you all kinds of suggestions. More that you'd know what to do with ;-) We keep that group's archive here:

The signal to noise ratio is identical assuming the wiring doesn't pickup some junk from the vehicle electronics. However, you won't be able to take advantage of the S/N ratio in a vehicle. The acoustic background road and engine noise level is so high, the low level sounds coming from the speaker are inaudible or drowned out by the noise. Try whispering to a passenger while on the freeway for a clue as to how it works. Within reasonable limits (about 40dB), you could have all kinds of garbage, crap, noise, junk, ignition noise, alternator whine, etc coming from the speakers, and you would not hear them over the road noise. To aggravate the situation, most commercial CD's, including the MP3 ripped versions, have a very poor dynamic range, where everything is compressed to absurdity. Unless you're listening to classical music, there are no quiet passages, or low level subtleties, that you can hear. It's *ALL* loud music. Therefore, S/N ratio and dynamic range don't have much meaning in a noisy vehicle. Of course, if you drive to some place quiet, turn off the engine, and then listen to the music, S/N and dynamic range are now important. However, with the engine off, you won't pickup any junk from the vehicle electrical system, so noise pickup in the wiring is not terribly important.

Of course if you ask the same question of a real audiophile (audio fanatic), you'll get a completely different answer. You gotta have that kilowatt power amplifier, monster cazapitor power filter, welding cable Kelvin bridge wired speakers, quad shielded differential gold plated audio cables, and acoustic foam lining in the trunk. Oh yeah, you gotta have fiber optic audio (ToshLink) to reduce electrical noise pickup.

Sigh...