How to install a 5 channel amplifier with a radio that only has 4 channel pre-amp outputs

"What do I do about the subwoofer inputs. My radio only has front and rear RCAs"

We get this question often when customers install a 5 channel amplifier with a USA-230 or USA-630 radio.

In order to install a 5 channel amp on a radio with only 4 channel outputs, you will run the RCA cables or high-level inputs directly from the outputs on your radio to the front and rear channels of the 5 channel amplifier. You will leave the subwoofer channel empty! (Please Note: Kicker does not designate Front or Rear, you will just run the amp to Amp 1 and Amp 2)

All the 5 channel amplifiers we sell have selectable input switches. Some will call it 2/4/5, 2/4/6, Internal or External, Amp2 or Sub. These settings allow you to tell the amplifier whether you are connecting 2, 4 or 5(6) channels to the input side of the amp. For radios such as the USA-230 in the USA-630 which do not have that subwoofer pre-out, you will only be connecting 4 input channels into the amplifier. Do not worry about the subwoofer input, the amplifier will take care of that for you.

Simply connect the RCAs or speaker wire inputs into the amp and set the appropriate switch on your amplifier to either "4", "Amp2", or "Internal", depending on the amplifier manufacturer. The amplifier will take the signal that is coming from the radio for those 4 channels, sum it, filter out the high frequencies, and send the low frequency sound to the subwoofer.

If you want control over the subwoofer the best way to do this and we do recommend it with just most subwoofers anyways is to add a remote bass knob. Adding a remote bass knob gives you a fast and easy way to adjust the bass up or down from the driver seat. Bass is not consistent across all recordings or music genres. It is nice to be able to change it to your liking on the fly, by simply turning a dial. An example is if you switch from George Strait to Led Zeppelin. Chances are that the bass levels of those 2 artists will be drastically different and you will want to turn the subwoofer up or down so that it sounds like you are there, watching them play it live.