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How to Match Your Car Subwoofer and Amplifier

Tips for Finding the Right Car Components for Your Car Stereo System

A side view of a car.A subwoofer is an excellent addition to improve the sound in your aftermarket car stereo system. Subwoofers add fullness to music, giving off rich, deep notes that any music lover will appreciate.

But in order for a subwoofer to sound great, it needs to be paired with the right amplifier. Matching these car stereo components will make a significant difference in the quality of sound and ensure that your car stereo system is working properly.

When you’re ready for your new car stereo installation, consider these tips for finding the right subwoofer and amplifier for optimal sound.

Basic Concepts

Let’s go over some of the basics of subwoofer and amplifier use, pairing, and more. We’ll also cover some common terminology and how it all fits together.


Impedance is the electrical resistance of a speaker—in this case, subwoofer—that restricts the flow of electricity. Impedance is measured in ohms. And the impedance of a subwoofer affects the load of an amplifier.

The impedance rating of a subwoofer represents the load an amplifier will sense on its output. For example, an amp might run at 550 watts with subs wired at 4 ohms, and 1100 watts with subs wired at 2 ohms.

Most subs have 2-ohms or 4-ohms impedance ratings. And matching impedance with amps is fairly simple when only using one or two subs. But it becomes more complicated as the number of subs installed increases.


Amplifiers power subwoofers. And the amount of power that a subwoofer can handle is represented in peak watts for peak power handling and Root Mean Square (RMS) watts for continuous power handling.

A sub’s RMS rating is the one to pay attention to since it refers to the amount of power the sub is capable of handling continuously and on a regular basis. Peak power handling is the maximum amount of power a sub can handle without getting damaged.

Amps have an RMS watt range rating, referring to the minimum and maximum power ranges produced by the amp.

The Importance of Pairing

To ensure your car stereo system has excellent bass, you need to find an amp that matches your sub. In other words, the amp’s capabilities need to match the subwoofer’s specifications to work properly together.

For the best sound quality, make sure the RMS watts of the sub and amp match.

Finding the Right Amp for Your Sub

If you already have a sub, here are the steps to finding the right amp. Note that if you plan to wire together multiple subs in your car audio system, they must all be the same impedance and coil type to ensure they are all powered evenly. While different types of subs must all have their own separate amps.

Find the Sub’s RMS Rating

For multiple subs, multiply the number of subs by their RMS ratings for a total RMS rating. The amp you choose will have to be capable of powering 75% to 150% of the total RMS rating for the entire subwoofer system.

Find the Total Impedance

Find the total impedance created by the subs you’ve wired together, depending on whether they are single voice coil (SVC) subs, one pair of terminals, or dual voice coil (DVC) subs, two pairs of terminals.

  • 1 SVC 2-ohms = 2 ohms of impedance
  • 1 SVC 4-ohms = 4 ohms of impedance
  • 1 DVC 2-ohms = 1 ohm or 4 ohms of impedance
  • 1 DVC 4-ohms = 2 ohms or 8 ohms of impedance
  • 2 SVC 2-ohms = 1 ohm or 4 ohms of impedance
  • 2 SVC 4-ohms = 2 ohms or 8 ohms of impedance
  • 2 DVC 2-ohms = 2 ohms or 8 ohms of impedance
  • 2 DVC 4-ohms = 1 ohm or 4 ohms of impedance
  • 3 SVC 2-ohms = 6 ohms of impedance
  • 3 SVC 4-ohms = 1.3 ohms of impedance
  • 3 DVC 2-ohms = 1.3 ohms or 3 ohms of impedance
  • 3 DVC 4-ohms = 2.7 ohms or 6 ohms of impedance
  • 4 SVC 2-ohms = 2 ohms or 8 ohms of impedance
  • 4 SVC 4-ohms = 1 ohm or 4 ohms of impedance
  • 4 DVC 2-ohms = 1 ohm or 4 ohms of impedance
  • 4 DVC 4-ohms = ohms or 8 ohms of impedance

Find an Amp to Match Power and Impedance

Choose an amp that can put out power in the total RMS wattage range from step one, and at an impedance load the subs form, based on their wiring, from step two.

Car stereo amps range from one to six channels. A mono-channel amp is often ideal for powering subwoofers since it can output a lot of power with low impedance.

Finding the Right Sub for Your Amp

Find the Amp’s Power Range

The sub’s RMS watts rating must match the amp’s power range for optimal sound. Find the amp’s power in RMS watts at 4 ohms, 2 ohms, and 1 ohm.

Choose the RMS power rating you’d like to achieve. Your sub’s total impedance will be the load impedance (ohms) of that rating.

Decide on the Number of Subs

Take the RMS power rating you chose from the previous step and divide it by the number of subs you want in your car stereo system. The result is the target RMS rating you will need for each sub.

Divide the target RMS rating by 1.5 to get the minimum RMS rating that will work for each sub, and then divide the target number by 0.75 to get the maximum RMS rating.

Combine Impedance with the Number of Subs to Determine Coil Configurations

Based on the impedance chosen in step one and the number of subs you decided on, here are the possible coil configurations you can use for your subs:

  • 1 Sub = DVC 2-ohms
  • 2 Subs = SVC 2-ohms or DVC 4-ohms
  • 3 Subs = SVC 4-ohms or DVC 2-ohms
  • 4 Subs = SVC 4-ohms or DVC 2-ohms
  • 1 Sub = SVC 2-ohms or DVC 4-ohms
  • 2 Subs = SVC 4-ohms or DVC 2-ohms
  • 3 Subs = DVC 2-ohms or DVC 4-ohms
  • 4 Subs = SVC 2-ohms or DVC 4-ohms
  • 1 Sub = SVC 4-ohms or DVC 2-ohms
  • 2 Subs = SVC 2-ohms or DVC 4-ohms
  • 3 Subs = SVC 2-ohms or DVC 4-ohms
  • 4 Subs = SVC 4-ohms or DVC 2-ohms

Choose Subs that Suit Impedance and Power

Choose subs that are rated within the RMS wattage range you calculated in step two, and that are either SVC or DVC based on the configurations and impedance from step three.

For more information on upgrading your car stereo and the right audio components to choose, contact the car stereo experts. They can help you find the right sub, amp, and other car components to improve your vehicle’s sound quality and your overall driving experience. 

About AudioMotive

For over 10 years, AudioMotive has and continues to be, Ottawa’s premier vehicle upgrade experts. With more than 25 years of combined industry experience, we proudly specialize in all things related to HID lighting and mobile electronics sales and installation.