Car Audio Amplifier Function/ Installation Guide

1. Speaker connection – Never connect cables with the chassis ground. This may destroy your amplifier. Check that your speakers are connected correctly which means plus (+) to plus (+) and minus (-) to minus (-). Recommended speaker cable from 2.25mm to up. 
2. BATT+ – Battery + terminal. The +12 Volt power cable must be connected with a fuse in linenear the battery + terminal. 
3. REM – Remote terminal. The remote cable must be connected with the radio remote terminal so that the amplifier will switch ON and OFF automatically with the radio. If there are two or more amplifiers installed together, it might be necessary to add an additional relay. 
4. GND – Chassis ground terminal. The chassis ground cable must be connected very tight on a nearby massive and electric conductive place. 
5. Gain – Gain control regulates the sensitivity of the amplifier to match the signal output voltage of your source unit. The gain control is not a volume adjustment. Use high quality music and increase the volume of your source unit to 75% posit, set the gain at the minimum and then increase gain slowly (clockwise). Stop at the first sign of distortion, then lower the gain a little (counter clockwise) to achieve clear undistorted music at the maximum level. 
6. Remote Bass Level Control – When using the remote bass level control you can adjust the volume in the driver seat. 
7.  RCA audio input – These RCA audio inputs connect with your radio RCA outputs. Please use car audio RCA cables, otherwise it nay be disturbed. Keep these cables as short as possible. To avoid disturbances from your car electronics, please do not close the existing car cables when you install the RCA cables. If your radio has only one set output, please use a suitable Y-RCA adapter. If your radio has only speaker output, you must use a HIGH LOW LEVEL adapter.
8. Fuse –  To protect the amplifier when current drawn is more than rated. Never replace a fuse with a higher amp fuse. Never replace a burnt fuse before checking the system when there is a malfunction. 
9. Bridge in – This RCA jack receives signal from the master amplifier when this amplifier is bridged as slave. DO NOT use input jacks when the amplifier is working as slave. All the functions will be adjusted by the master amplifier. 
10. Bridge out – This RCA output is sent out bridge signal to another same Class D amplifier in bridging configuration.
11. Low Pass Filter – Filter out high frequency that the woofer cannot play. Adjust this knob to match the woofer’s frequency response. 
12. Phase – Adjust the phase of speaker output, to match the woofer’s phase with the car or match phase with other speakers.
13. Subsonic – Filter out unwanted too low frequency. This function will increase the power handing of your woofer’s. It can adjust the frequency filter from 10Hz (OFF) to 50Hz. 
14. Bass boost level – Adjust the boosted frequency from 0 to 12 dB.
15. Bass boost Frequency – Adjust the boosted center frequency. The frequency can be adjusted from 0Hz to 80Hz, use combine with bass boost level adjusting. 
16. Alarm Indicator – When this LED light up, the amplifier may in self-test mode (when powered up) or malfunction. Shut down the amplifier immediately can find the reason before power up amplifier again. 
17. Run indicator – This LED will light up when the amplifier is working properly, it will flash or shut down once amplifier in self-testing or malfunction. 

These functions or terminals may vary from amplifier to amplifier. However these are the most commonly seen function terminals seen in most car audio amplifier. Understanding the meaning behind each terminal.