Installing A Car Amplifier – How To

A car amplifier is a device that provides a considerable boost to your audio system and also improves the quality of your sound output. Whilst a vehicle’s sound system will have small amps fitted as standard, these are only basic models and do not provide the boost and clarity that a dedicated amp system can. You can notice a huge difference in the quality of your audio when using a quality amplifier and it really can make a whole world of difference to your driving experience.

Many car enthusiasts who purchase an amplifier will pay the manufacturer or a specialist garage to install the device. Whilst this may seem like the logical thing to do, it is actually quite easy to manually install an amp in your car, yourself, with minimal effort and electrical knowledge.

If you enjoy working on your vehicle and want to experience the satisfaction of installing your own device (and saving a significant amount of money in the process!), this 'How To' guide aims to provide you with all the guidance you need to efficiently install a car amplifier yourself!

Equipment List And Considerations

So you have purchased your amp and are itching to install it; Where do you start?

First and foremost, it is important to find a suitable place in your vehicle that your amp can be safely installed. Things to keep in mind: ensuring the amp can have sufficient air flow, that you have enough space to work in and connect the wires, and that the wires from your speakers and battery can easily be connected and concealed. 

Recommended / Common Amp Locations are:

  • Trunk - primary for a larger amp, providing plenty of space.  Ensure you have wires and cables of sufficient length.  
  • Under seat - a more central location closer to front speakers.  Shorter wires and cables are sufficient, and less prone to noise.  Only a smaller amp will fit.

Before starting the installation, it is first advisable to gather your equipment and be clear on exactly what you want to achieve. The equipment list will depend largely on what your amplifier kit contains – not all amplifiers come equipped with a full wiring kit. The following is a basic list of equipment that you may require to install your amp:

  • Amplifier
  • Wiring (Mains power, inline fuse, ground wire, RCA cables, speaker wires, connector plugs)
  • Spare wire
  • caret-right
    Wire clippers
  • caret-right
    Wire Crimper
  • caret-right
  • caret-right
  • caret-right
    Rubber grommet
  • caret-right
  • caret-right
    Amplifier Mount

Once you have gathered your equipment and chosen a suitable position, please ensure you have set aside sufficient time for installation – you will likely need a few hours in total, but the satisfaction will be worth it!

Phase 1 - Preparing your Amplifier

First things first: before positioning the amp and fixing it in place, you should ensure it is in working order, that it's components are in place and all the relevant wiring is ready.

Consider fixing the amp to a mount to give it additional stability instead of simply fixing the amp straight to the vehicle body. Once you are prepared, you will fix your amp in place in your position of choice.

Phase 2 - Fitting / Positioning your Amplifier

Next, ensure you disconnect the negative battery terminal to ensure no damage to your vehicle or devices (as well as your own safety!). Next, you must create a hole through your vehicle's firewall - the separating wall between the engine bay and dashboard - to feed the wires through to the battery.

Some vehicles will have a factory hole you can use; if not, drill a hole through the firewall and fit a rubber grommet to it (this protects the wire from damage as it rubs on the metal firewall). This is important - if you leave the hole unfinished, as the power wire moves, the jagged edges of the surface could cut into the wire and cause it to eventually break.

Once the hole in the firewall is prepared, you can fix your amp in place. Mark out the desired position with a pencil or pen, and also mark out the position of the mounting holes. Once you are satisfied with the positioning, you can then drill the mounting holes and screw your amp in place – consider creating small pilot holes first before you drill straight through so you can avoid any errors. Ensure the mount/amp is secure and that the ports and wiring connections are accessible.

Once you have done this, run the power cable of the amp through to the car battery. Ensure that you connect an inline fuse holder to the power wire and then connect the power wire to the battery. The inline fuse holder acts as protection for your vehicle in the event that your amp has a power shortage – if you had no fuse holder, your vehicle could burn up and its other electrical systems could become damaged. The fuse holder should be positioned as closely as possible to the car's battery. Your amp now has a power source and is fixed in place.

Pat yourself on the back for a good job so far - have a nice stretch, and now you're ready to proceed to the next phase.

Phase 3 - Wiring your Amplifier

So now that the power cable has been fixed, you can turn your attention to the remaining wires. You will have either have the required wires in the amplifiers wiring kit or have purchased them separately.

For ease of installation, we have listed each wiring sequence separately:

Ground Wire – The ground wire is hugely important and protects the vehicle and devices from electrical surges. The ground wire must be connected to a bare metal surface within your vehicle. It is important to ensure the metal surface is clear – if it has any dirt or paint on it, is advisable to sand the surface down to ensure a metal on metal connection. Once the surface is completely bare, connect the ground wire.

Subwoofer Wires – If you have a subwoofer, you must connect it to the amplifier to create a complete circuit. The ports on the amplifier and the wires on the subwoofer should be clearly labelled so it is a case of matching the right wires with the right ports.

RCA/Speaker/Remote Wires – These wires will vary depending on your audio system. Each wire should be connected from the amp to the corresponding port on the head unit of your stereo system. The remote wire is to ensure that your amplifier switches on and off when your stereo system does – if this isn’t connected then your amp will remain switched on and thus will drain your car’s battery. Most audio systems will have a remote wire, but if yours doesn’t, you should connect the remote wire to the power wire of your audio head unit.

Once you have connected all the relevant wires, you can connect the negative terminal to the battery once again.

Phase 4 - Tuning and Testing

The final stage is testing and tuning - an amplifier must be manually tuned to set an appropriate level of gain and to gauge the correct volume level. If you have an oscilloscope you can use this to automatically tune your amplifier, but unless you are a car electrician, you are unlikely to own one, therefore, a manual approach must be taken.

To manually tune your amplifier you must first adjust each of the settings/controls:

  • Input level controls: set to their minimum setting
  • Tone controls: set to no boost (i.e. bass, loudness, and treble)
  • Equalizer settings: set to the central position

Once you have done this, grab your favourite high-quality audio source - we are about to put your new amp into use!  Ensure the music you have chosen is of high quality with minimal distortion.

With the song now playing, steadily turn the volume up until just before you start to hear distortion - this is the sweet spot. Now that you have found the ideal volume, you can then move onto the next audio setting and repeat the same process. Repeat these same steps for each component of the amplifier until you have each setting at its maximum level without distortion

Once finished, your amplifier and audio system should now be tuned perfectly and the quality of your music should be a pleasure to listen to!

Final Tips

Always remember to take time during each phase, double checking your work and ensuring that the wiring is secure and undamaged. Furthermore, before you drill any holes or fix anything in place, check what is behind the surface you are interacting with! We are sure that many people have simply started blindly drilling holes in their vehicle and cut right through an important wire or cable – do not make the same mistake!

Hopefully, you will have found our guide helpful – as you can see, installing an amplifier is a process that, with a little patience, just about anyone can perform. Providing you have the correct tools and follow these instructions carefully, there is no reason why you cannot successfully install your very own car amplifier.