Quick Overview The GM-A4704 4-channel amplifier will greatly improve the sound quality in your vehicle. This amplifier powers your front and rear speakers with 40 watts RMS each, allowing you to hear more of the finer details in your music, especially when you turn up the volume to overcome road noise. With this amplifier, you can run your front speakers with the “A” channels and combine the “B” channels to drive a subwoofer. You can also set this versatile amp to 2-channel mode to send 130 watts RMS each to a pair of component speakers or subwoofers. Additionally, speaker-level inputs allow you to add this amplifier to a factory-installed audio source that does not have pre-amplified outputs.