Originally Posted by
dleccord
why would you want to run 4 gauge in and (2) 4 gauge out? get some 1/0 and run that to the back. from there, distro 4 gauges to each amp. the amps will run cooler and efficient that way. while you're at it, you can do the big 3 with 1/0 gauge to help reduce any dimming.
0/1 is great, but it's probably 3x the cost of 4 ga or more and 4ga should be adequate. Running 4ga from a distro fed by 4ga (other than being hard to find) isn't going to get you any benefit.
Remember there are three characteristics that determine how you size
1. Acceptable voltage drop
2. Diameter of the wire
3. Length of the wire
Typically, you select the acceptable voltage drop and fix that. Next decide the length of wire you need and the current you need to carry. That will determine your diameter of wire.
Here's a more in-depth tutorial:
http://www.the12volt.com/info/recwirsz.asp
If you look at a 500W amp (typical current draw of 60A or so), an 8 ga wire should be good for about 6 feet - if you locate your distro block within 6 feet or so of your amp - there will be no issues.
Just because an amplifier can accept a 4ga input, doesn't mean that it needs it.