How To Match Car Amps and Car Subwoofers

How To Match Car Amps and Car Subwoofers

As you venture deeper into your next car stereo installation, you’ll realize that successfully matching a car amplifier and subwoofer is more complex than simply matching power ratings. The term “ohms” often surfaces during this process, perplexing you about its significance. In this article, we’ll discuss how to match a car amp with a car subwoofer, focusing on the practical aspects rather than delving into Ohm’s Law. By understanding key terminologies and following a systematic approach, you can avoid blown fuses and achieve an optimal audio experience in your car.

Car Subwoofer & Car Amp Terminology 

To begin the matching process, it is crucial to grasp the following terminologies:

  • Channels. In car audio, “channels” refers to the pathways through which power or information flows. A single-channel amplifier has one terminal for power distribution, while a two-channel amplifier has two terminals, and so on.
  • Bridging. Bridging involves combining two channels to create a single channel. It is commonly used with 2- or 4-channel amplifiers to power a single speaker or subwoofer.
  • Monoblock Amplifiers. Monoblock amplifiers have a single channel, typically powering one subwoofer at lower frequencies. They are an excellent choice for running one or two subwoofers.
  • Two-Channel Amplifiers. These amplifiers provide two channels that can wire in different ways. You can connect each channel to a separate subwoofer or bridge the channels to power one.
  • Four-Channel Amplifiers. Four-channel amplifiers primarily power speakers but can also power subwoofers by bridging the channels in a specific configuration.
  • Single/Dual Voice Coil Subwoofers. Subwoofers come with either a single voice coil (SVC) or dual voice coils (DVC). DVC subwoofers offer more wiring options than SVC speakers, allowing for different impedance levels.
  • Ohm. An ohm is a unit of electrical resistance. In the context of audio, it represents the resistance to the flow of energy. Amplifiers often have power ratings at different ohm levels, and selecting the right ohm load is crucial for optimal performance.
  • RMS (Root Mean Square) Power. This value represents the continuous power output that both the amplifier and subwoofer can handle without causing damage or distortion. It is crucial to match the RMS power ratings for optimal performance.
  • Peak Power. Also known as maximum power handling, peak power represents the highest power level a component can handle momentarily. While peak power is often more prominent in ads, the RMS power truly matters for sustained performance.

Matching Subwoofers and Amplifiers

With the basic terminology now out of the way, it’s time to match subwoofers with amplifiers. Depending on how you plan out your car audio build, you may have already chosen your desired amplifier or subwoofer(s). Depending on what component you have first, the process of matching the other will be slightly different.

You Have The Subs, But No Amp

Before choosing the correct car amp, it’s important to note that if you plan to use more than one subwoofer, they must be the same. If you have two or more subwoofers connected to the same amplifier with different power requirements, you will have an unbalanced sound that will be easy to notice. If you plan to use different types of subwoofers throughout your car, make sure that their own amplifier powers them.

To pick the correct amp, you will need to find the RMS of your subwoofer. If you are using two or more subwoofers, you’ll multiply the RMS by the number of subs. You will want to find an amp that outputs around the same amount of power.

Following the RMS, you’ll have to find the impedance of your system. The total impedance will change depending on whether your subs are SVC or DVC, and the number of subs in the system. As an example:

  • 1 SVC 2-ohm sub is 2 ohms
  • 1 SVC 4-ohm sub is 4 ohms 
  • 1 DVC 2-ohm sub can be 1 ohm or 4 ohms
  • 1 DVC 4-ohm sub can be 2 ohms or 8 ohms 
  • 2 SVC 2-ohm subs can be 1 ohm or 4 ohms 
  • 2 SVC 4-ohm subs can be 2 ohms or 8 ohms 
  • 2 DVC 2-ohm subs can be 1/2 ohm, 2 ohms, or 8 ohms 
  • 2 DVC 4-ohm subs can be 1 ohm, 4 ohms, or 16 ohms

When looking at car amp specifications, the sheet will note what RMS the amp can deliver at a particular ohm. To choose the correct amp, you must find one that can provide the RMS at the total impedance you calculated. 

You Have The Amp, But Not The Sub

If you have the amp, but still need the subs, you will largely do the same process as above but in reverse. 

First, you will look at the RMS of the amp at different impedances (4ohm, 2ohm, etc.). You’ll pick one with a matching RMS if you have just one sub. If you plan on having more than one sub, you will divide the amp’s RMS by the number of subs to give you the RMS you should be looking for in each sub.

Finally, you will need to use the impedance you picked in the first step to find what ohms you should be looking for in your amps. 

Let Us Match Your Car Amp and Car Sub

Matching a car amplifier and subwoofer requires a systematic approach that considers power ratings, impedance compatibility, and wiring configurations. 

While it’s possible for anyone to match these audio components on their own, why not take the guesswork out of it and make use of the professionals at ProCarSound&Security? Our team of dedicated audio experts and installers can help you pick the best amplifier and subwoofer for your sound system and install them seamlessly into your vehicle. 

If you need help making sure your components are compatible with one another or need any other audio-related help, please don’t hesitate to contact us.

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