Hook Up 3 Amps in a Car Together Following Our 7 Steps Guide

Last Updated on December 17, 2023 by CarAudioHunt

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If you don’t want to settle for a standard car stereo's flat, uninspiring sound, multiple amps can be the solution. Or even when you're geared up with high-performance speakers and subwoofers, setting multiple amps in your car's audio system can upgrade your listening experience.

Whether you're a seasoned audio enthusiast or a curious beginner, our guide on how to hook up 3 amps in a car is your ticket to an unparalleled auditory experience. Let’s get into transforming your car's audio from ordinary to extraordinary.

Before diving into the sea of wires and connections, let's pause for a crucial prelude: preparation with the necessary tools and DSP.

Tools You Will Require

By having your hands on the following tools, you can expect to have a seamless installation experience: 

  • Battery
  • 2 Distribution Blocks
  • 3 Compatible 2-channel or 4-channel Amplifiers (as per your requirements)
  • 2 Component speakers
  • A Digital Signal Processor (DSP)
  • In line Fuse
  • Ground Nut
  • Wire Cutters and Spritters
  • Digital Multimeter
  • Auxiliary Fuse Block
  • 2 Co-axial Speakers
  • Subwoofers

Is DSP Necessary for Multi-Amp Installation?

A Digital Signal Processor (DSP) is connected between the head unit and the amplifiers to serve as a central control point for audio processing. It combines the functions of crossovers, equalizers, and line output converters to tune specific frequencies precisely. DSP further enables fine-tuning of the audio output of each amplifier, controlling aspects like time alignment, equalization, and crossovers.

While not deemed an absolute necessity, a DSP can improve control over the audio landscape. It's especially beneficial if you strive for audio perfection and desire crystal-clear sound. As a result, a DSP is highly recommended for multiple amplifiers and high-quality sound.

The Steps to Setting up 3 Amplifiers

We are now going in-depth about the 3-amp installation process with easily comprehensible steps.

Step 1: Connecting Power Cables with Battery

First things first: safety. Like always, you will have to disconnect the battery before you start working.

Calculating the required amperage is key to ensuring your amplifiers get the power they need without overloading the system. Take a moment to sum up the wattage of your amplifiers; let's say you have 3 amplifiers of 600 watts, 7000, and 800 watts.

  • The formula to calculate the current (I) required is I = P/V, where P is power in watts, and V is voltage (typically 12-14.4V in-car systems). 
  • So, you'd have (600+700+800) / 13 ≈ 162 amps. Since amps are not 100% efficient, you should consider it around 80% efficient and adjust the current accordingly: 162 / 0.80 = 202.5 amps.

Your next work is to choose the right gauge for your power wire. As such, a zero gauge wire, capable of handling over 300 amps, will be suitable for this theoretical example. Then, you will have to connect the power cable first to the battery’s positive and negative ends to that of the amplifiers.

Step 2: Passing Power Cables through a Grommet

For effective cable management, it is essential to properly route the power cable from the vehicle's interior to the engine bay. You need to locate a suitable grommet in the firewall - the barrier between the engine compartment and the cabin. The optimal pathway typically lies beneath the glove compartment, opposite the steering wheel.

Step 3: Adding In-Line Fuse with Power Cable & Battery

An in-line fuse is the first line of defence against potential electrical mishaps. You need to trim the power cable to the appropriate length needed to bridge the gap between the in-line fuse and the battery's positive terminal. Attach one end of this cable to the in-line fuse and then securely connect the other end to the battery's positive terminal.

Step 4: Mounting the Amplifiers

When mounting your amps, you should consider ventilation, ease of access, and cable management. Maintaining a 3 feet distance between the amplifier and subwoofers is ideal to avoid noise distortion. A safe and secured mounting place, like the trunk or behind the back seat, can be the key to this step.

Step 5: Routing the Power Cable to the Distribution Block

This distribution block is a central hub that streams power from the battery to the amplifiers. A 3-way distribution block is typically used for systems with three amplifiers if you’re opting for wiring with a distribution method.

After putting it in place, connect the main power cable from the battery to the distribution block's input. It ensures that the block receives power directly from the battery. Next, connect three power cables from the distribution block's output terminals to each amplifier. 

You then need to connect 3 ground wires from the amplifiers to another 3-way distribution block. Extend a single ground cable from this block to a grounding point on the car’s metal body, such as a ground nut.

Step 6: Connecting RCA Cables from the Head Unit to Amps

This step sets the stage for the four different methods of connecting your amplifiers – daisy chaining, using a distribution block, independent wiring, and signal splitting.

a. Daisy Chaining

Daisy chaining is a method that involves connecting your amplifiers in a series, linking them together like a chain. This technique is often favored for its simplicity and minimalistic approach.

It requires connecting the RCA output jacks of one amplifier to the RCA input jacks of the next amplifier using RCA cables. The 3rd amplifier’s RCA input jack should be connected to the RCA output jack of the 2nd amplifier with an RCA cable.

b. Using a Distribution Block

Using a distribution block is like having a central hub in your car's audio system. It's a more centralized and organized way to manage your RCA connections.

Here, you run a single RCA cable from your head unit to the distribution block, which distributes the signal to each amplifier. You will need to set up the outside side of the block with each amplifier’s RCA input jacks with individual RCA cables.

c. Independent Wiring

Independent wiring is the audio system's equivalent of giving each amplifier its own personal pathway.

You will have to run separate RCA cables directly from the head unit to each amplifier. Then, plug each RCA cable’s 1 end into the RCA output jacks on the head unit and the other into the RCA input jacks on each amplifier. You should be careful regarding neatly arranging and securing the RCA cables to prevent tangling and damage.

d. Signal Splitting

Signal splitting is similar to a branched tree. The RCA output from the head unit is like one main trunk, which is divided into several branches akin to the amps' inputs.

You should first attach RCA splitters to the head unit's RCA output to divide the signal into multiple outputs. Then, RCA cables are run from each output side of the splitters to the RCA input jacks on the amplifiers.

Step 7: Integrating Speakers and Subwoofers

Integrating speakers and subwoofers into your car's audio setup is like adding the final, crucial pieces to an intricate puzzle. The speaker wires will go to the amps’ positive ends. After all the speakers and subwoofers are attached to the amplifier, try powering the amplifiers by connecting the negative terminal to the battery. Turn on the head unit; if power connections are fine, you should see the light on the amplifiers.

Then it should look something like this after installing the 3 amps in your car audio system. But it can vary if you opt for a different type of wiring or configuration.

If you have two speakers in the front, it’s best to use an amplifier for connecting the speakers and another amplifier for both the right and left speakers on the rear. We recommend connecting a subwoofer with a lone amplifier, as the subs require a lot of power.

Troubleshooting for Better Longevity

You should regularly check connections, ensure cables are secure and not frayed, and keep an ear out for distortion or unusual sounds. It will not be just about fixing issues as they arise but about preemptive care to extend the life and quality of your audio system.

Wrapping Up

We have journeyed through the complexities of adding 3 amps together to improve your system. Now, it's time for you to get started with the installation confidently and then enjoy the fruits of your labor.

It does not require saying that your drives will never be the same again. They'll be transformed into immersive audio experiences, whether you are just listening to the radio news or your favorite band music. 

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