Amplifier Wiring and Setting the Gain Level

This guide will help you through wiring and setting gain levels on your car audio amp. Using the instructions below, you should be able to get the most from your system while avoiding costly damage. Steps and settings may vary slightly for different manufacturers and amplifier types.

Before You Get Started

DIY (At Your Own Risk)

Our warranty only covers manufacturer defects. While this guide will help you avoid damage, we cannot foresee every possible scenario. If you (or anyone helping you) damage any SoundQubed product by using it incorrectly, we cannot refund or replace those damaged products.

If you are uncomfortable completing any of the following steps, call us at (405) 600-1936 Monday-Friday, 9 a.m. to 5 p.m.

Know Your Gear

Make sure your amplifier, subwoofer(s), and charging system are compatible in terms of power handling and impedance. You may need to upgrade your charging system to properly power large amps. Possible charging system upgrades include a big 3 wiring upgrade, adding a secondary car audio battery, and/or a secondary alternator.

Knowing the available power from your charging system and the power handling of your speakers is especially important if you are only upgrading the amplifier in an otherwise stable, well performing audio system.

Preparing to Install

If you are amplifying new subwoofers, make sure you break them in correctly.

Connections, Mounting Locations, and Disassembly:

  • Decide on an amp mounting location
  • Video/manufacturer instructions on how to remove panels
  • Fuse block mounting location (within 12” of the battery)
  • Ground wire connection to frame

What You’ll Need:

Wiring to Your Amplifier

Safety Precautions

Do not attempt these instructions with your vehicle running. Always use caution when dealing with electrical connections to avoid personal injury or damage to your vehicle or car audio equipment.

You’ll need to drill at least one hole in your vehicle’s frame. Always know exactly what is on the other side before you drill. When choosing a drilling location stay away from moving parts, fuel tanks, fluid reservoirs, hoses, and cables.

Wires passing through drilled holes require a protective grommet. Don’t leave a wire in contact with a rough, metal edge. Because the wire will vibrate against the sharp edge, it will eventually wear through.

Power wires and RCA audio cables run together can cause noise that will come through your speakers. Space their runs as far apart as you can.

Ground Connection:

  • Choose a location on the vehicle’s frame for your ground connection (do not use seat belt bolts)
  • Remove paint or rust from the ground location using sandpaper
  • Clean the bare, shiny metal of the frame thoroughly with isopropyl alcohol
  • Drill a hole large enough for a bolt (no self-tapping screws) that will fit through the ground cable eyelet 
  • Bolt the ground eyelet to the vehicle. If you are unable to reach the back side of the frame, add threads to the frame hole using the correct tap for your ground connection bolt

Power Connection through the Fuse Block:

  • Choose a fuse block mounting location within 12 inches of the battery
  • Connect power wire between the fuse block and battery terminal
  • Run power wire from the fuse block to the amplifier power terminal 
  • Keep the power run as short as possible to avoid a loss of amperage

Remote Turn-On, RCA cables, and Remote Gain Knob:

  • Run your remote turn-on wire, RCA cables, and gain knob control cable to the head unit and amplifier
  • Connect the remote turn-on to a 12V “accessory” power source (a 12V “constant” source will run down your battery when the vehicle is off)

Connect to Your Speakers

  • Using the appropriate wire gauge, connect the amplifier’s speaker outputs from your to your speakers or subwoofer(s)
  • Confirm that your amp is receiving and sending power
  • Reassemble the head unit and dash panels

Setting the Gain Level

Initial amp settings:

  • Low Pass Filter (LPF): 90-100Hz
  • Subsonic: 30Hz (assuming an enclosure tuning between 35-45Hz)
  • Master-slave switch: Master
  • Bass boost: Off
  • Amp gain: 0
  • Remote bass knob: 75%
  • Head unit equalizer (bass, mid, high): 0

Adjusting the gain level:

  • Insert your Audio CD or USB drive
  • Play an audio track with moderate to high volume
  • Turn the head unit volume to 75%.
  • Slowly increase the gain on the remote bass knob. Watch the clipping indicator light. If it begins to flicker at all, stop increasing the gain.*

*The clipping indicator light should not glow solid or flicker continuously, or stay red on transients. A clipped signal will cause damaging heat buildup in speaker/subwoofer voice coils. Burnt voice coils are rarely if ever a manufacturer defect covered under warranty. This type of damage is almost always caused by user error, including frequent clipping. Bluetooth/streaming audio sources are a common source of clipping because of unpredictable signal levels of each track.

amplifier, crossover settings, gain level, installation, tech topic, wiring


  • I want to build my dream sound system for my car. But every single item i peak is sold out or not the ohms u need.. Im willing to pay for what i like .. Not disrespect… Please if some one cant help me out whit this i really appreciate… Thanks. Aka benny build

Leave a Reply

Your email address will not be published.

Contact our customer support team by calling (405) 600-1936.
between 9 a.m. - 5 p.m. (CST), Monday through Friday.