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How Many Channels Do I Need on My Car Amplifier?

When shopping for a new car amplifier, one of the first things you’ll need to decide is how many channels you need.

The answer to this question depends on a few factors, including the number of speakers you have and how you want to configure your sound system, so how many channels you may need on the amplifier? Let’s find out.

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In general, you’ll want one channel for each speaker, so if you have a pair of speakers in either front or rear, a 2-channel amplifier will be sufficient. If you have installed front and rear speakers, you need a 4-channel amplifier. If your car has a subwoofer, you will need an amplifier with another two channels or a monoblock.

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Tip: Since it is typically best to only have a single amplifier, you will most likely want a single 4-channel amp (link to Amazon) if you only have four speakers in your car.

Four-channel amplifiers are typically less expensive than two separate two-channel amps and take less room in the car.

Keep in mind that if you’re using a four-channel amplifier for two pairs of speakers, you won’t be able to control the volume or frequencies of each pair individually. So if you want that level of control, you’ll need two amplifiers, one for each pair of speakers.

In the article below, I will guide you through the process of choosing a suitable amplifier for your car sound system.

How Many Channels on an Amp Do I Need?

Depending on the number of speakers, you will need an amplifier with a different number of channels in the car:

You’ll need a two-channel amplifier for one pair of speakers in either front or rear. You can also install two separate monoblocks to power each channel individually, but this solution is rare in a typical car system, although it offers the best sound quality.

For two pairs of speakers, you can either get a four-channel amplifier or two two-channel amplifiers. One four-channel amplifier is the standard and most common solution for this type of setup and also the cheapest one.

For one pair of speakers and a subwoofer, you’ll need either a four-channel amplifier or a two-channel amplifier and a monoblock. For the single voice coil subwoofer, you can choose either a stereo amplifier and bridge it into one channel or use the single-channel monoblock amp.

However, for the subwoofer with two voice coils, you must use a two-channel amplifier because each voice coil has to be connected to a separate channel.

For two pairs of speakers and a subwoofer, you will need either a five or six-channel amplifier, but you can also install a four-channel amplifier and a monoblock. A five-channel amplifier can be used for speakers and a single voice coil subwoofer. However, for the dual voice coil sub, you have to use a six-channel amp and bridge two channels into one mono channel.

How Do Multi-Channel Amplifiers Work?

Multichannel amplifiers work by taking a signal from the stereo, and by using an independent power source, it’ll create a more powerful signal to send to the speakers.

how many channels do i need on my car amplifier

A powerful multichannel amp allows for all the speakers to have a single power source that can be easily stowed out of sight. A single power source also reduces the chance of introducing unwanted noise to the system.

How to Connect Your Speakers and Subwoofers to Your Multichannel Amplifier

When connecting 4 speakers to a 4-channel amplifier, your biggest concern will be which speaker’s wire connects to which input.

You will see both an A and a B to your inputs. A will correspond with the top row of inputs, while B corresponds with the bottom row. In most cases, your front speakers will connect to A while rears connect to B; however, there are some amplifiers with different power outputs for A and B channels. 

On your amp, there should be marked left and right for your inputs as well. This will correspond with the side of the car that the speaker is on. 

Connecting your speakers to their corresponding inputs allows you to maintain fader and balance in your audio. The last thing you need is to mix left with right channels in either front or rear of the vehicle.

The most important part of connecting your subwoofer to a multichannel amplifier is ensuring your amplifier can handle your speakers and subwoofers.

In your amp’s handbook, you should be able to find its power rating. Check this with how much power your subwoofer and speakers need, but actually, you should check this before purchasing an amplifier, making sure it has enough power. 

If the power needed exceeds the power given by the amp, you may not experience the greatest quality audio that you could, and you may risk damaging speakers.

how to match car amplifier with speakers

Depending on the number of channels, you may need to use parallel speaker connections. This requires connecting both the front and back speakers of both sides.

Once you are sure your amplifier can handle speakers and subwoofers, the process to connect the subwoofer is just about the same as speakers.

If you’re connecting both speakers and subwoofers, you want to connect the sub to your amplifier’s bridge channels.

This is usually located on the left and right of your amp’s B. However, some amplifiers are different than others, and it is important to check which input is your amp’s designated bridge channel.

How to Connect More Than One Speaker to the Same Channel

This process is fairly simple and common when using a subwoofer as well as speakers on the same amplifier. It’s called parallel speakers. When connecting your speakers, you’ll want to take the wires from both the front and back of both sides and connect them to one input terminal.

The important thing to consider when making parallel connections is the power transfer and impedance of the speakers. In this article, I reviewed different connection types depending on speakers’ impedance, so check it out.

When not using RCA cables, this means you will be connecting four wires to 2 input terminals. You’ll want to combine both the front and rear speakers’ positives, then combine both negatives of the front and rear speakers.

Repeat this process for both the left and right side, and you will be able to connect four speakers to 2 channel inputs. It is ideal when connecting a subwoofer as well as your speakers. It may cost some variation in the audio in the front and rear of the car, but this is usually offset by the subwoofer. It also still maintains balanced audio and fader.

how many channels my car amplifier should have

Should My Amplifier’s Number of Channels Match My Number of Speakers?

In most cases, yes, you will want as many channels as you have speakers. This allows a more rounded out and whole sound to be played thanks to an equal distribution of power to each speaker.

This equal distribution allows each speaker to be powered independently and played the way that the music requires. If each speaker has full independent power, then it will be able to play at different volumes that create an overall better audio quality.

This rule varies only slightly when applying a subwoofer into the equation, or when your sound system is advanced and you have for example dedicated amplifier to each speaker.

While it is typically best to give a subwoofer its own single channel or stereo amplifier, there may not be a whole lot of room in your car for another amplifier.

In this case, it is entirely possible to hook up both your subwoofer and speakers to a single multichannel amp, as long as this amp is capable of powering all of your systems.

The best amplifier that can handle such power requirements and one I had a real pleasure to test is Audison Voce AV 5.1. I have reviewed Audison flagship in this article, so check it out

Even if your speaker does not have enough input to accommodate 4 speakers and a subwoofer, let’s say you’re using a 4-channel amp, you can still connect all 5.

Using the non-RCA cable side of your amp, you will be able to connect two speaker cables to one input. You’ll just want to make sure that you are using both the positives from the front and backside of the left or the right for each input.

So, you’ll want to put the positive wires of the front and rear of the right into a single positive input, as well as its negatives into the negative input. You’ll then repeat this for the left side.

This process can easily be applied to a car with 4 speakers and only a 2-channel amplifier but check the speakers and amplifier’s impedance to make sure it will not damage your sound system.

While this process is entirely possible as long as the amp’s power can accommodate as many speakers as you are using, it does come at the cost of some quality.

You won’t get quite as much variation in sound using a 2-channel amplifier for 4 speakers. This can often be overlooked when using a subwoofer as well, since it will easily make up for the lack of variation, assuming it can be properly powered.


With a matching number of channels to speakers, your speakers will have full power independence and operate as the music needs them to. With options of amplifiers with 5 and 6 channels, this is entirely possible.

It is also still recommended that if you have multiple speakers and a subwoofer, you use an independent single-channel amplifier for subwoofers if you have the space to spare. Using more than one amplifier always gives more flexibility to power both multiple speakers and a subwoofer.