i have super super slight alternator whine. noticed it when tweets were moved to custom pillars from the stock door locations. its only noticeable when you look for it with the radio off. when music starts playing... you couldn't hear it at all. no noise when car is off.What kind of noise? Hiss or alternator whine?
Noise from speaker wire is unlikely, it contain a high level signal unlike the low level signal in your RCAs. Lowlevel outputs will always be more sensitive to outside noise. I've run speaker cables along power wires and OEM harness countless times without any issues.
Is the noise present with the car off? Checked grounding?
Wow that's the first time I've heard of a situation where the highend cables actually have a useThere was a white paper done by Dan Wiggins of Adire Audio, comparing UTP (I think it was CAT5) and shielded coax twisted-pair (Belden 8412). In testing, Dan ran the signal wire down the hood of his Ranger (I think), and measured signal in vs. signal out. I believe he also used a subwoofer coil to introduce an inducted signal). There was a significant difference between the two, and the 8412 mopped up on the UTP.
With that said, this is only the case IF you're running signal wire near high-noise devices. That makes a significant difference in what you end up with, results-wise.
Vehicles are definitely a high (electrical) noise environment, much as pro audio environments can be. The Belden 8412 is a mic cable, which is twisted within a coax shield. It's definitely not cheap, but making your own isn't terrible and you can avoid some of the possible problems that way.Wow that's the first time I've heard of a situation where the highend cables actually have a use