How to Wire a 4 Channel Amp to 4 Speakers

Written by bryan clark
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How to Wire a 4 Channel Amp to 4 Speakers
Improve your sound with a four-channel amp. (car music image by Andrey Kiselev from

Installing a four-channel amplifier is a great way to bring life to the speakers in your car. When given the correct amount of power, car speakers can really sound phenomenal. The best way to give the speakers the power they need is to upgrade your car stereo system with a four-channel amp.

Skill level:
Moderately Challenging

Things you need

  • Amplifier
  • Amp wiring kit
  • Speaker wire
  • T-taps
  • Drill
  • Metal bit
  • Rubber grommet
  • Pliers
  • Screws
  • Phillips screwdriver
  • RCA cables (two sets)

Show MoreHide


  1. 1

    Find a suitable location to mount your four-channel amp. Under one of the seats is a good place in most cars. Once you find a suitable location, disconnect the negative terminal from your battery, and then the positive. You don't want to risk electrical shock, so it's quite important to disconnect the power to the car.

  2. 2

    Crimp a ring terminal onto the power wire that came in the amp kit. You'll need to attach the power wire to the positive terminal on the battery, and the easiest way to do this is by sliding a large ring terminal over the battery post and then putting the factory plug over it, before tightening them both down.

  3. 3

    Cut the power wire about 8 inches past the battery terminal. Attach the fuse holder to the end of the power wire you just cut, and then reattach the power wire at the other end of the fuse holder. The wire should go from the battery to the fuse holder in no more than 6 to 8 inches. Anything more is a fire hazard. Insert the fuse into the fuse holder before continuing.

  4. 4

    Run the power wire through the firewall of the car. If you can't find a factory hole, you can make one with a drill and a metal bit. Make the hole just small enough to fit the power wire, and not much else. Use a rubber grommet to seal the hole so that water doesn't find its way into the passenger compartment.

  5. 5

    Run the power wire from the firewall to the location of the amp. You can hide the wire under the carpet or centre console if you choose.

  6. 6

    Remove the stereo from the dash. If you have an aftermarket stereo, this should be as easy as inserting two keys (which should have come with the stereo) into the sides of the stereo until you feel them click, and then pulling the radio out of the dash.

  7. 7

    Plug two sets of RCA cables into the stereo. In order to properly utilise a four-channel amp, you need at least two sets of preamp outputs. Make sure you make a mental note, or mark the wires so that you know which ones are plugged into the front RCA jacks and which are plugged into the rear.

  8. 8

    Grab four pieces of speaker wire and strip the ends. Make sure they are at least long enough to run from the radio to the amp location. Too long is better than too short, as you can always cut the excess.

  9. 9

    Use T-taps to tap into the speaker wires for each channel of the amp (right front, right rear, left front, left rear). You can find all four speaker wires right behind the radio. Most often, aftermarket wiring harnesses have all of the wires labelled for you, but if they aren't labelled, check Reference 1 for the stereo wiring guide which will tell you which colour wire goes to which speaker.

    To use a T-tap, put the top part of the mouth part of the T-tap over the wire you want to splice into, and squeeze it with pliers. It will form a connection with that wire and has an end to plug your new wire in below it. Plug in the new speaker wire (that you'll run to the amp) into the bottom section, and squeeze it with pliers to form a tight seal around the wire.

  10. 10

    Find the remote wire, and tap it with a T-tap behind the radio. Make sure you have enough excess wire to make it from the radio to the amp. If it's not labelled, use the wiring chart provided in Reference 1 to find the 12-volt accessory wire (remote).

  11. 11

    Pull the RCA cables, remote wire and the newly tapped speaker wires into the hole made by removing the radio. Pull these wires under the dash, and collect the excess so that you can run them back to the amp location. Run these to the amp, and hide them under the carpet or centre console if you prefer.

  12. 12

    Connect the RCA cables to the appropriate RCA connections on the amp. Ensure that the front RCA is connected to the front input, and the same for the rear. Plug the remote wire into the plug on the amp labelled "Remote" or "12-volt accessory."

  13. 13

    Plug the power and ground into their respective locations. To ground your amp, remove a small section of carpet, crimp a ring terminal onto the end of the ground wire, and screw it directly into the metal part of the floor. This has to form a secure connection with metal at all times in order for your amp to work.

  14. 14

    Connect the speaker wire for all four speakers (that you tapped behind the radio) into their appropriate places on the amp. Most amps require that you insert the wires and then use a Phillips screwdriver to screw down a clamp over the top of them. Be sure that they are in the correct spot. Right front positive goes to right front positive, and so on. The amp should be marked with this information. If you didn't mark the speaker wires, or you forgot what was what, you can always identify them behind the radio.

  15. 15

    Secure the amp in place with screws or Velcro. You want to ensure that it doesn't move and pull a wire loose. You can put the radio back into the dash now by pushing it back into the hole. It's snug when you feel it click.

  16. 16

    Connect the positive battery terminal, and then the negative. Ensure that your power wire is secure on the positive battery terminal.

  17. 17

    Adjust the gains on the amp to your liking. Once it sounds good to you, it's ready to go.

Tips and warnings

  • Always disconnect the battery when working on the electrical systems of your car.

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