LOC vs. High Level Input and Wiring
 

So I finally decided to put an amp and sub in my FR-S and noticed after I took the stock HU out that it had no RCA.

After looking through the forums, I think I found the solution but I wanted to ask once more to make sure I'm doing it right.

First of all, I bought a LOC for $20 but then realized my Boss M1100 Monoblock amp has stereo level inputs. So I'm wondering which would be better to tap into the speakers.

My other question is am I correct to tap into the Signal wires in the rear factory amp's harness (pins 3,9,4, and 10 if memory serves right). Or should I tap into the Speaker wires (pins 1,5,2,6 I think)?

I do plan on having a power line from the battery to the amp.

Thanks in advance!

My FRS has stock RCA out for a sub... weird. At least I'm 99% sure it does.

Either way should be fine, you're not going to notice it with just a sub. If you had a super hi-fi front end setup you'd definitely want to tap signal wires and not speaker level wires. If you do speaker level, use your LOC. If you do line level, use a hacked RCA cable.

The speaker wires are after processing in the amp to be fed to the base drivers. You want to tap the signal wires, which are theoretically unprocessed at that point. They are also speaker level, but not much power behind them. An external loc is generally not as clean as the hi level input circuitry built into an amp or active crossover, but especially not a $20.00 one. Return the LOC and go directly into the high level input of the amp from the car's signal wires.

This is what I did. Works fine.

Sweet. Thanks for the help.

I decided to just go through the speaker level inputs, however the harness that came with the amp for the speaker level input are 24 gauge wires which seem too small...plus there aren't any tap splices for wires that small.

Went ahead and ordered the Metra harness for the factory amp (both male and female) to make a sort of extension area so I don't have to splice into the factory amp harness.