As I upgrade my sound system, I am taking this opportunity to learn more about car audio and signals in general. I love this stuff. So I have a quick question about wiring gauge.

As you decrease the gauge of the power and ground cables, does this help cut down on possible noise interference and ground loop problems? For instance, 20 ft. of 8 gauge power cable vs. 20 ft. of 4 gauge power cable. Would either be more likely to have more noise get into the system? Or does gauge ONLY affect the amount of power it can have flow through it?

On one hand, I would think that lower gauge = bigger wire = more sensitive to misc. input. However, somehow my gut intuition is that lower guage will be more likely to be less noisy. Given the length of cable (20ft), 12volt recommends nothing higher than 4 gauge. My amp that I'm powering is a modest 90Wx4 btw. The amp and crutchfield both say 8 gauge is fine. So I'm a little torn whether a lower gauge is going to help me in any way - OR whether it might actually adversely affect the sound quality (by picking up more noise).

A related question, how sensitive are ground cables to picking up noise? Would 3 feet of cable, in actual practice, be any better than 4 feet of cable?

 

Also, lower gauge kits tend to come with bigger fuses.

If my amp can only handle 40A before it blows its internal fuse, then wouldn't an 80A fuse between the battery and the power cable be pretty useless? What is going to draw that sort of current??

 

Short to ground.

 

exactly, fuse at the battery is there to protect against fire incase the power wire is grounded directly to the chassis.