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How to match subwoofers and amplifiers

Find the right amp for your sub or sub for your amp

The secret to great bass is making sure your subwoofers and amp are evenly matched and will properly work together. And this article will help you figure out how to do just that — match amplifiers and subwoofers.


etting the right sub for an amp, or the right amp for a sub, is like solving a puzzle. A subwoofer has impedance (measured in ohms) which represents the "load" an amplifier will sense on its output. An amplifier will put out different amounts of power (watts RMS) based on the impedance load it "sees."

Solving the puzzle

The amplifier's capabilities (X watts RMS into Y ohms) needs to match the subwoofer's specifications (Y ohms and can handle X watts RMS). Your goal is to get those two variables to match for both the amplifier and the subwoofer.

Below, we cover the important basics of power-matching, impedance, and planning for the number of subs you want, and we approach the situation from both sides of the system:

  • Part A: You have the subs, which amp should you get?
  • Part B: You have the amp, which subs should you get?
  • And also, Part C: You have neither amp nor sub, and want help deciding how to begin.

Start with either part of this article you want, but A and B are both worth a read.

Illustration showing a subwoofer and possible amplifier options.

Part A — You have the subs, which amplifier should you get?

When you already have a subwoofer or two, you need to find an amplifier that will give them they power they need to deliver the bass you want.

The subwoofers need to be the same

Multiple subs wired together must be the same coil type and impedance. If they’re not, the power won’t divide evenly between them, and some subs would probably be over-powered while others get under-powered. If you want to run different types of subs in a system, each type needs to have its own separate amp.

Step 1: How much power? Find out the “watts RMS” rating of the sub

Then, multiply the number of subs you have by the RMS rating of each, to get their total RMS rating. You want to make sure the amp you choose will supply no more than the sub system’s total RMS rating.

Step 2: What impedance? The results of combining coils and subs

Figure out the possible total impedance(s) that the subs can be wired together to form.
SVC = A subwoofer with a single voice coil. It has only one pair of terminals.
DVC = A subwoofer with a dual voice coil. It has two pairs of terminals.

  • 1 SVC 2-ohm sub can only have 2 ohms of impedance
  • 1 SVC 4-ohm sub can only have 4 ohms of impedance
  • 1 DVC 2-ohm sub can have 1 ohm or 4 ohms of impedance
  • 1 DVC 4-ohm sub can have 2 ohms or 8 ohms of impedance
  • 2 SVC 2-ohm subs can have 1 ohm or 4 ohms of impedance
  • 2 SVC 4-ohm subs can have 2 ohms or 8 ohms of impedance
  • 2 DVC 2-ohm subs can have 1/2 ohm, 2 ohms, or 8 ohms of impedance
  • 2 DVC 4-ohm subs can have 1 ohm4 ohms, or 16 ohms of impedance

For more combinations of subs and their impedances, see Subwoofer Wiring Diagrams.

Step 3: Pick an amp that can do both — X watts at Y ohms

Look for an amplifier that can put out power up to the RMS wattage you’ve figured in Step 1, at an impedance load the subs can be wired to form, from Step 2.

Estimating amp power at the odd impedance values:

  • 8 ohms — figure on the amp putting out half the power it would at 4 ohms
  • 6 ohms — figure on the amp putting out three-quarters of the power it would at 4 ohms
  • 3 ohms — figure on the amp putting out the average of what it would at 2 ohms and at 4 ohms
  • 2.7 ohms — figure the same as for 3 ohms, and add a few watts
  • 1.3 ohms — use the 1-ohm spec and take away a few watts
Alpine S-W8D4

Example: Finding an amp for your subs

You have two Alpine S Series S-W8D4 8" subwoofers and you want the right amp for them.

  • They are DVC 4-ohm subs rated at 300 watts RMS each.
  • Two 300 watts RMS subs together need a maximum total of 600 watts RMS.

Using the chart in Step 2, 2 DVC 4-ohm subs can be wired together to form a 1-ohm, a 4-ohm, or a 16-ohm load.

The last is too high a load to be practical, so you’ll look for an amp that can put out up to 600 watts RMS into either a 4-ohm load, or a 1-ohm impedance load:

  • up to 600 watts RMS x 1 at 4 ohms, or
  • up to 600 watts RMS x 1 at 1 ohm

Among Crutchfield’s selection of amplifiers you’ll find:

Kicker KEY500.1

Kicker KEY500.1 subwoofer amplifier

Any one of these high-quality amplifiers would work well with those subs. It doesn’t matter which impedance an amp plays through — 600 watts RMS through a 4-ohm load produces the same volume as 600 watts RMS through a 1-ohm load.

Illustration showing a amplifier and possible subwoofer options.

Part B — You have the amplfier, which subs should you get?

If you already have an amplifier, you need to find a subwoofer (or two) that will be a good fit for the power it can deliver.

Step 1: What can the amp do? Find the RMS power ratings of the amp at different loads

Find the amp’s power, expressed in “watts RMS”, at 4 ohms, at 2 ohms, and, if it can, at 1 ohm. Pick the power you’d like to achieve. The load impedance (ohms) of that rating will be what you want your subs’ total impedance to be.

Step 2: How many subs do you want?

Divide the power you picked in Step 1 by the number of subs you want. This number is the target RMS rating for each of the subs you’ll choose. 

Step 3: What impedance does each sub need to be and how many voice coils?

Using the impedance you picked in Step 1 and the number of subs from Step 2, cross-reference the possible coil configurations that you can use: 

1-ohm 2-ohms 4-ohms
1 sub DVC 2-ohms SVC 2-ohms
DVC 4 ohms
SVC 4-ohms
DVC 2-ohms
2 subs SVC 2-ohms
DVC 4-ohms
SVC 4-ohms
DVC 2-ohms
SVC 2-ohms
DVC 4-ohms
3 subs (1.3 ohms)*
SVC 4-ohms
DVC 2-ohms
(3 or 2.7 ohms)*
DVC 2-ohms
DVC 4-ohms
(6 ohms)*
SVC 2-ohms
DVC 4-ohms
4 subs SVC 4-ohms
DVC 2-ohms
SVC 2-ohms
DVC 4 ohms
SVC 4-ohms
DVC 2-ohms
* Estimate amp power at the odd impedance values like in Part A, Step 3, above.

Step 4: Pick a sub that works for both — (SVC or DVC) X-ohms, Y watts RMS)

Look for subs that are rated at the wattage you figured in Step 2, and are configured as you found in Step 3. This might sound confusing, so let's walk through an example and it'll make sense.

JL Audio JD500/1

Example: Finding subs for your amplifier

You have a JL Audio JD500/1 amplifier and you want it to drive two subwoofers

  • The amp is capable of 250 watts RMS x 1 at 4 ohms and 500 watts RMS x 1 at 2 ohms.

Let’s say you choose to maximize the amp’s potential and want the system to put out 500 watts RMS. This means your subs have to be wired to form a total impedance of 2 ohms.

Two subs on a 500 watts RMS amp will want about 250 watts RMS each.
So you’ll look for subs each rated for 250 watts RMS or more.

Using the chart in Step 3, for two subwoofers, a final 2-ohm load can be achieved with either two SVC 4-ohm subs or two DVC 2-ohm subs.

So, you’ll look for two subs that are either SVC 4-ohms or DVC 2-ohms, rated for at least 250 watts RMS each:

  • 2 SVC 4-ohms, at least 250 watts RMS, or
  • 2 DVC 2-ohms, at least 250 watts RMS

Among Crutchfield’s selection of subwoofers you’ll find:

Kicker CompC 10"

Kicker CompC 10" component subwoofer

All these subwoofers will sound their best when amplified with the proper amount of power. Differences in size have more to do with tonal qualities and frequency response than with power performance. And optimizing performance is the point of matching subs and amps together.

How to match subs and amps

Part C — You have neither amp nor sub, and want help deciding how to begin

Check out our other article, All About Subwoofers to learn the basics of how much bass you need and how to choose your subwoofers. 

And of course, if you have any questions, contact our expert advisors and they'll be happy to help you build your system. 

  • Steep

    Posted on 3/18/2023

    I recently received a sundown audio e10 v4 dvc 4ohms. I was wondering if a 5 channel amp like the rockford fosgate r2 750 x 5 would be suitable.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 3/20/2023

    Steep, That amplifier's sub output and that subwoofer should work well together.
  • Sergio Moreno from San Bernardino, Cali

    Posted on 2/26/2023

    I have 2 P2 Dual 4 OHM 400rms(12's) in a enclosed box I want to get the max out of them. They are currently on a R500x1D Amp but I feel like they can push out more. Is this the correct amp for them maybe I can wire them differently or is there another amp I can install

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/27/2023

    Sergio, Those two DVC 4-ohm subs rated for 400 watts RMS each would play louder with an amplifier that could send them up to 800 watts RMS at 1-ohm or 4-ohms, like an Infinity Kappa One K.
  • Yetta from Ice town

    Posted on 2/18/2023

    Hey Buck, Can I safely power a 300w rms 4ohm svc sub with a 150w rms 1 ohm amp? Budget build: using guts from an 11hs8, Heard it was 1ohm. How does one measure that? Thanks.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/20/2023

    Yetta, Amplifiers that can handle 1-ohm loads can also handle 2- and 4-ohm loads. There's no detailed information about the component sub or amplifier inside that Kicker compact powered subwoofer system, nor did you say what new sub you have, so we can't help you with matching information.
  • Jeremy M. from Franklin, TN

    Posted on 2/8/2023

    I have an MTX 2150X amp that puts out 300W bridged at 4 ohms. I really want to pair it with one of the JL Wedge or Micro Sub enclosures because the small box size is perfect for the space behind the rear seat in my 2018 F150 Super Crew - along with the 300W rating on those particular subs. But all of those appear to carry a 2 ohm rating, with the exception of the 8" micro sub model, which I'm afraid won't be enough output for me. If I'm stuck on one of those 10" JL models do I just need to find a good mono block amp that's 2 ohm stable and move on from trying to salvage the MTX for this setup?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/9/2023

    Jeremy, There are almost no benefits in using a 2-channel amp to drive a subwoofer system. Most 2-channel amps can't drive loads lower than 4 ohms when bridged, and don't have enough power to drive 2 subs. Mono, 1-channel amps are designed to work with a wider range of impedances, and have tone controls and filters specifically made to help reproduce bass.
  • Daniel Gowen from Troy,Tennessee

    Posted on 2/7/2023

    Best kicker amp for 2 kicker comp rt 4 ohm 12s in a ported box

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/8/2023

    Daniel, The best Kicker amp we have available to power those subs is the 46CXA800.1T.
  • Raegan David from Columbia

    Posted on 2/7/2023

    I just bought 2 skarr 12" subs they are 4ohm 800watt each, what amplifier should I get for them? Thank you

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/8/2023

    Raegan, If you're referring to Skar VD12-D4 subs, they're DVC 4-ohm subs rated for 500 watts RMS each - and a good amp for them will put out up to 1000 watts RMS at 1-ohm, like a Rockford Fosgate T1000-1bdCP .
  • Jeff Buck from Anna

    Posted on 2/7/2023

    The car I recently bought has a Hertz HDP1 1000W RMS Class D Monoblock Amp. The previous owners removed whatever the amp was hooked up to. What size sub or subs should I look for as far as power handling goes?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/8/2023

    Jeff, There's no way of knowing what subwoofer will actually fit in your car, without knowing what car you have. As far as the amplifier is concerned, any sub rated up to 1000 watts RMS will work. Like an MB Quart RW1-304 DVC 4-ohm sub wired as a 2-ohm load.
  • Floyd

    Posted on 1/31/2023

    What about impedance rise? Realistically a 500 rms amp isnt going to produce 500 watts constantly..... it will vary with frequency. I have a single Hutchinson Origin 15" dual 4 ohm 750 watt that I am needing a amp for. I was thinking about the avatar 2100.1D . Any suggestions?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/1/2023

    Floyd, We don't usually mention impedance rise, duty cycle, nominal specifications, or varying frequency responses because, realistically, very few people would truly understand them and their relationships. You could probably find an amp to match your sub yourself by rereading Part A of the article carefully, or hiring a professional car audio installer.
  • Chase Garrett Jarvis from Goreville

    Posted on 1/30/2023

    So if I have 2-SVC 2ohm subs. I can't use a 2 channel amp right?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 1/31/2023

    Chase, Without knowing precisely what amp and subs you're referring to, we can't help you with accurate advice. Most 2-channel amps don't have enough power to drive 2 subs - but your 2-channel amp may work fine for your subs.
  • KATIE from Chattanooga

    Posted on 1/23/2023

    I bought a 10" JBL stage sub with a 900 watt output @ 225 RMS. Would you please recommend an amplifier? TY

    Commenter image

    Buck Pomerantz from Crutchfield

    on 1/23/2023

    Katie, That SVC 4-ohm sub rated for 225 watts RMS (you should never use peak ratings for system designing) will work great with an amplifier that can put out up to 225 watts RMS at 4-ohms, like a Kenwood KAC-M3001. Give us a call so an Advisor can help you get everything you need (sub, amp, box, and wiring) for a successful subwoofer installation.

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