Wiring subwoofers — what's all this about ohms? (2024)

How wiring affects your sub's output

Wiring subwoofers — what's all this about ohms? (1)

by Crutchfield's Buck Pomerantz

Wiring subwoofers — what's all this about ohms? (2)

Confusion concerning watts, amps, and ohms has been around for as long as people have been putting subwoofers in cars. Watts and ohms are entangled in a series of mathematical formulas that link them intimately together such that when one of them undergoes a change in value, the other often does too.

Briefly, here's how subwoofer impedance works

  • Amplifiers provide the electrical pressure in a circuit.
  • Ohms measure the resistance, or load, against that pressure.
  • Watts measure how much power is released as work.

So, using one of those math formulas, an amplifier that provides 100 watts of power through a 4-ohm speaker, will produce 200 watts through a 2-ohm speaker, because it's easier to push that reduced load.

Voice coil makes sound — amplifier pushes it

At the heart of every speaker and sub is a voice coil. This is the device that puts up the electrical resistance and performs the work. (The amplifier provides the power.) The resisting property of a coil is called its impedance and is measured in ohms. The lower a speaker's impedance, the easier it is for an amp to supply power to it. Problems arise when the amp's output meets very little resistance (low impedance) and it tries to put out more power than it was designed to produce. This leads to the amplifier overheating and then, hopefully, shutting down to protect itself from burning up.

You don't want the amp to over-do it

So the capability of an amplifier has to be considered before applying a load to it (hooking up a speaker). The manufacturer's specifications indicate an amp's minimum impedance requirements. Almost all amps can drive a 4-ohm load. Most amps can work with 2-ohm loads on each channel, but not when the channels are bridged together. Some amps can drive a load as low as one ohm.

Wiring subwoofers — what's all this about ohms? (3)

The two channels of this Pioneer GM-A3702amp can be bridged by wiring the subas indicated

Wiring options change a sub's impedance

To add to the confusion, in multiple-sub systems, the total impedance depends on how the subs and their voice coils are wired together — in parallel or in series. Parallel wiring means that the connection ends of each device are connected to the same things — plus to plus, and minus to minus. Series wiring means that the devices are wired one after the other — a plus of one to a minus of another.

When speakers or voice coils are wired in series, you add their impedances together to find their total impedance. Two 4-ohm speakers wired in series have a total impedance of 8 ohms. When speakers or coils are wired in parallel, however, the formula for their total impedance is more complicated. When the impedances of all the devices are the same, their total impedance, when wired in parallel, is that impedance value divided by the number of devices. For example: four 4-ohm speakers wired in parallel have a total impedance of 1 ohm.

Subwoofer wiring video

For more information about subwoofer wiring, watch this video. One of our senior tech support staff explains how to wire subwoofers in parallel or series, and how that affects the amplifier's impedance load.

Dual Voice Coils give you even more wiring options

Subwoofer manufacturers make subs with dual voice coils (DVC) to take advantage of this difference in wiring schemes, so the user has more freedom of system design. A DVC 4-ohm sub can be wired into a system as a 2-ohm or as an 8-ohm load. A DVC 2-ohm sub can have a total impedance of 1 ohm or 4 ohms.

Wiring subwoofers — what's all this about ohms? (4)

This Rockford Fosgate DVC 2-ohm sub has a built-in jumper so you can choose whether it has a 1-ohm or a 4-ohm total impedance

An example using 4 subs:

If I wanted 4 subs in a system, I might consider using 4 DVC 2-ohm subs, each with their voice coils wired in parallel to make them each 1 ohm subs, and then wire the 4 of them in series so my amplifier could drive them as a single 4-ohm load. Or, I could wire the voice coils in series, making them all 4-ohm subs, and then wire the subs in parallel so the amp would see the total load as one ohm. It would depend on my particular amplifier — which load it would do the best with.

Match power to power — use RMS only

To make subwoofers sound their best, they should be powered by an amp whose RMS output rating comes close to or even slightly exceeds the total of all the subs' top RMS ratings. If you want to run three subs whose RMS ratings are 300 watts each, you'll need about 900 watts RMS of power to run them.

Underpowered subs won't sound good or play very loud. Then, if you were to turn up the input to compensate, the amp could end up sending out clipped or distorted signals that could damage the subs. It's okay to overpower your subs a little bit, as long as the signal's distortion-free, because they're made to withstand occasional peaks well beyond their normal RMS rating.

What's right for you?

The sub and amp you need depends on what you want to hear. If you plan on listening to music at moderate volume levels or have a smaller car, a subwoofer with a lower power handling rating, say 100 to 250 watts, and a matching amp is a good combo.

The ultimate goal is to have the amp send its full power to subs that can handle it. The object of using different wiring options to optimize the impedance is to get the most power out of the particular amp and subs you have at hand.For more wiring specifics, check out our subwoofer wiring diagrams.

If you want to get right into choosing a subwoofer, take a look at our top-rated and best-selling subs. If you have any questions about choosing the right gear, contact ouradvisors by phone or chat. They'll be glad to help!

Comments (480)

Please share your thoughts below.

  • Marcus S from brush

    Posted on 11/16/2023

    I have the Fusion ap 82400 running 6 Fusion sig. 3 6.5's, and a Fusion AP12000 monoblock to power 2 Fusion sig. 3 12's (SVC 4ohm) Would the correct way to wire the subs be?.parallel which would make the ohm load for the subs being 2 ohm. Or would it be better to wire the subs in series? If I'm understanding all of this correctly? In parallel the amp would put out 1100 w rms, would that be divided between both subs? 550w rms each?Any guidance is appreciated! None of the literature with the amp or subs says anything about running both 12's on the ap12000. thanks!

    Wiring subwoofers — what's all this about ohms? (5)

    Wiring subwoofers — what's all this about ohms? (6)

    Buck Pomerantz from Crutchfield

    on 11/16/2023

    Marcus, Those two SVC 4-ohm subs will work well with that amplifier wired like this wiring diagram. This way, each sub will get exactly half of the available 1100W of power - 550W each.

  • Dawson

    Posted on 5/1/2023

    So the cone in my car's sub cracked, and I'm looking to replace it. I've looked on this website, and it gave me a list of "compatible" subs, but I'm not completely sure. The OEM sub was a 2O 8", but I don't know what the RMS was, and I can't find anything online about the specs of the amp in the car. I'm not really looking to do a full overhaul of the sound system, but I don't really know how to find a speaker that will 100% work with the OEM stuff. This confusion is mainly caused by the fact that I don't know much about audio stuff, and the fact that the list of compatible subs has different ohm values than the stock sub.

    Wiring subwoofers — what's all this about ohms? (7)

    Wiring subwoofers — what's all this about ohms? (8)

    Buck Pomerantz from Crutchfield

    on 5/1/2023

    Dawson, With questions like this, it's always better to have a conversation with a real live human. Give us a call and talk to one of our Advisors. We can help you choose the right sub to fit in your vehicle and give you the right advice on how to install it.

  • Raymond from Austin

    Posted on 4/25/2023

    I have a 6 channel amp (4 ohms: 100 watts x 6 chan. or 2 ohms: 150 watts x 6 chan.) and 4 - Kicker 4ohm Wakeboard speakers + a 4 ohm kicker marine subwoofer. I have tried to wire the subwoofer bridged to channel 5 & 6 but it completely made all the speakers not loud at all. Almost like not working. But if I wire the subwoofer to channel 5 and leave 6 empty - things work but the subwoofer bass only hits on certain songs. Is this a power issue? Ohms issue? IThe amp is NVX MVPA6The Speakers are Kicker 45KMTC8The subwoofer is Kicker 46CWTB84

    Wiring subwoofers — what's all this about ohms? (9)

    Wiring subwoofers — what's all this about ohms? (10)

    Buck Pomerantz from Crutchfield

    on 4/25/2023

    Raymond, It sounds like your amplifier may have problems. If you bought your amp from Crutchfield, you could call Tech Support for free help troubleshooting your system.

  • Jacob H

    Posted on 3/16/2023

    I have a 2015 Ford F350SD with the Sony OEM Premium system. I was checking to see if the SKAR VD--8 D4 (4ohm) 8" Subwoofer is compatible with the proper ohm and wiring harnesses? For now I am only upgrading two door panel speakers, Door Tweeters, and the Sub I mentioned. Will it work? Or will is the SONY a 2ohm system?

    Wiring subwoofers — what's all this about ohms? (11)

    Wiring subwoofers — what's all this about ohms? (12)

    Buck Pomerantz from Crutchfield

    on 3/17/2023

    Jacob, The factory subwoofer is a dual 2-ohm voice coil model. We recommend a dual 2-ohm voice coil sub as a replacement if you're retaining the factory amp.

  • Keith Thompson from BELLAIRE

    Posted on 2/2/2023

    I have a Harman Kardon sub amp in my 2001 bmw z3. Trying to connect a kicker cwrt67 4 ohm dvc subwoofer. What is the correct way to connect the 4 wires coming from the amp?

    Wiring subwoofers — what's all this about ohms? (13)

    Wiring subwoofers — what's all this about ohms? (14)

    Buck Pomerantz from Crutchfield

    on 2/3/2023

    Keith, When replacing a factory sub with an aftermarket sub, you should keep track of which wire went where and duplicate that setup. If you've lost track of that, you'll have to test the wires, as pairs, to see which carry signal and which are ground connections. You can use the new sub as the tester. Hook up two wires and see if they make a sound. And duplicate that for the other coil's wire.

  • Casey McClinton from Lakewood

    Posted on 1/27/2023

    I have two 2 ohm DVC subs. I've been running them as two 4 ohms in parallel for 2 ohms to the amp. I can also run them as two 1 ohms in series for two ohms. Will it make a difference in sound considering some of parameters might change?

    Wiring subwoofers — what's all this about ohms? (15)

    Wiring subwoofers — what's all this about ohms? (16)

    Buck Pomerantz from Crutchfield

    on 1/27/2023

    Casey, There should be no difference in tone or volume between the two wiring schemes. Tone is determined by the manufacturers' construction techniques, and the volume is determined by the amount of power applied. Both are the same in your example.

  • jessie gerdes from Beverly Hills

    Posted on 1/14/2023

    if i wire 2 2ohm dual voice coil to 4 ohm in 2 terminals will my jbl a600 mono pareral them back to 2ohm automatically? its built into the amp so i believe the answer would be yes the are skar ix 12s 250 rms 500 watts

    Wiring subwoofers — what's all this about ohms? (17)

    Wiring subwoofers — what's all this about ohms? (18)

    Buck Pomerantz from Crutchfield

    on 1/14/2023

    Jessie, Your mono, 1-channel amp has 2 sets of speaker output terminals, wired together inside the amp, for convenience, and if you hook a speaker to each terminal it would result in the two speakers being wired in parallel, cutting the total impedance in half. That's what happens when you wire two DVC 2-ohm subs, each wired to 4-ohms, to your amp using both sets of terminal.

  • I have two jl tw3 10 4ohm in a to spec ported box and have a p500x1bd amp what is the best wiring configuration? Thanks

    Wiring subwoofers — what's all this about ohms? (19)

    Wiring subwoofers — what's all this about ohms? (20)

    Buck Pomerantz from Crutchfield

    on 12/21/2022

    Jacob, The best way to wire that gear together is like this.

  • Chris from Penticton

    Posted on 12/4/2022

    How do I wire two 10" Sony xplodes 1100 watts to a Rockford m1200 1d?? I'm trying to run it at 2ohm.

    Wiring subwoofers — what's all this about ohms? (21)

    Wiring subwoofers — what's all this about ohms? (22)

    Buck Pomerantz from Crutchfield

    on 12/5/2022

    Chris, If those are Sony XS-L100P5W SVC 4-ohm subs, they're each rated for 300 watts RMS (600 watts RMS together) and can be wired together to form a 2-ohm load, but that amplifier will probably blow them to smithereens with its 900 watts RMS output at 2-ohms.

  • Wiring subwoofers — what's all this about ohms? (23)

    Buck Pomerantz from Crutchfield

    Posted on 9/17/2022

    AJ, If your gear is actually Skar Audio gear, then the safest way to wire them together is like this.

The easiest way to shop car audio online

Find what Fits your vehicle

Remove

Checking fit...

Related products

Loading...


Adding...

Pioneer GM-A3702 In stock 4.5 out of 5 stars89 reviews

$89.99

Loading...


Adding...

Rockford Fosgate Power T1D212 In stock 5.0 out of 5 stars29 reviews

$449.99 each

Loading...


Adding...

JL Audio 10W0v3-4 In stock 5.0 out of 5 stars277 reviews

$139.99

Loading...


Adding...

Sound Ordnance™ B-24 In stock 5.0 out of 5 stars180 reviews

$219.99

Shop our best sellers in

  • Loading...


    Adding...

    JL Audio 10W0v3-4

    In stock

    5.0 out of 5 stars277 reviews

    $149.99 -$10.00 Price break

    $139.99 each

  • Loading...


    Adding...

    JBL Stage 82AM

    In stock

    4.5 out of 5 stars36 reviews

    $79.95 -$20.00 Instant savings

    $59.95 each

  • Loading...


    Adding...

    Rockford Fosgate P3SD2-8

    In stock

    5.0 out of 5 stars127 reviews

    $209.99 -$40.00 Price break

    $169.99 each

  • Loading...


    Adding...

    Kicker 48CWR84

    In stock

    5.0 out of 5 stars49 reviews

    $99.99 -$25.03 Instant savings

    $74.96 each

  • Loading...


    Adding...

    Kicker 48CDF104

    Low stock

    5.0 out of 5 stars48 reviews

    $149.99

  • Loading...


    Adding...

    Kicker 48CWRT674

    In stock

    5.0 out of 5 stars47 reviews

    $119.99 -$30.03 Instant savings

    $89.96 each

  • Loading...


    Adding...

    Kicker 48CWR82

    In stock

    4.5 out of 5 stars34 reviews

    $99.99 -$25.03 Instant savings

    $74.96 each

  • Loading...


    Adding...

    Sound Ordnance™ Bass Bunker

    In stock

    5.0 out of 5 stars63 reviews

    $59.99

Related articles & videos

See all

  • Car subwoofer buying guide Our subwoofer shopping guide will help you determine which kind of subwoofer and bass system you need to get the sound you want. by Crutchfield's Bob B.
  • How to match subwoofers and amplifiers This step-by-step guide will help you make sure that your amps and subs are evenly matched and work well together. We explain how to select one to go with the other. by Crutchfield's Buck P.
  • Tuning your subs What does the gain control do anyway? How should you set the low-pass filter? This article describes how to tune your amplifier so that your subwoofer sounds just the way you want it to. by Crutchfield's Buck P.
  • What are dual voice coil subwoofers? Dual voice coil subwoofers are a popular choice among car audio enthusiasts who want more flexibility in wiring their sound systems. by Crutchfield's Bob B.
  • How to choose a subwoofer box Subwoofers in sealed boxes play "tight" bass, while ported boxes sound "boomy." Which type you need depends on the style of music you like and how you want it to sound. by Crutchfield's Buck P.
  • Subwoofers FAQ Which subwoofer will sound the loudest? Or the deepest? Which hits harder: one 12" sub or two 10" subs? How much power do I need? These answers and more in our FAQ. by Crutchfield's Crutchfield Writing Team
  • Subwoofer wiring diagrams There are many ways to connect subwoofers to an amplifier. Our wiring diagrams will help you find the best way to wire your subs and amps so you'll get the most powerful performance out of your gear. by Crutchfield's Buck P.
  • How to build a subwoofer box Helpful tips and step-by-step instructions for designing and building your own custom subwoofer box. We walk you through the math and the actual build in detail, so you'll know how to do it yourself. by Crutchfield's Robert F.
  • Headlights dim when the music plays Here we discuss the most popular fixes for an underpowered electrical system: the big 3 upgrade, a capacitor, a high output alternator, and a second battery. by Crutchfield's Buck P.

Compare the sound

SpeakerCompare

Patented Virtual Audio technology for auditioning speakers online

Recommended

Please turn active noise cancelling off for best results

You can change this setting any time by clicking 'Headphones' in the main menu.

Don't see your headphones?
Rent our Listening Kit

SpeakerCompare is protected by patents and patent applications owned by Crutchfield Corporation.

SpeakerCompare

Patented Virtual Audio technology

Audition speakers before you buy

SpeakerCompare simulates the sound of home and car speakers through your headphones. It lets you compare sonic characteristics between speakers so that you can make a more informed shopping decision.

To get started: For the best sound comparison, we recommend selecting your brand and model of headphones in the right-hand column, or if your headphones aren't listed, you can rent one of our Listening Kits.

SpeakerCompare is protected by patents and patent applications owned by Crutchfield Corporation.

Please select a track to continue

SpeakerCompare

What to listen for

Track notes

Artist

  • analyzer
  • log
  • linear
  • messages

We're here to help

For free personalized advice, call 1-888-291-8923. Our Advisors have listened to most of the speakers we carry, and can help you make the best choice for your system.

We'd love to know what you think

Select your headphones

Recommended

Please turn active noise cancelling off for best results

You can change this setting any time by clicking 'Headphones' in the main menu.

Don't see your headphones?
Rent our Listening Kit

Select a track to start listening

Audition speakers before you buy

SpeakerCompare simulates the sound of home and car speakers through your headphones. It lets you compare sonic characteristics between speakers so that you can make a more informed shopping decision.

Why selecting your headphones is important

SpeakerCompare tailors your listening experience to the exact headphones you have, so that what you hear is comparable to auditioning speakers side-by-side in person. Knowing which model headphones you’re using lets us remove any sonic coloring from your experience.

Two different listening modes

In an actual listening room, you'd find that some speakers play louder than others when fed the same amount of power. In equal power mode, you'll hear these differences in loudness as they naturally occur between speakers.

In equal volume mode, we've made the loudness of each speaker about the same. This gives you a more direct comparison of subtle voicing differences between speakers.

Nothing beats listening to speakers in your space

SpeakerCompare gives you a sense of the sonic differences. But performance in the real world is affected by the acoustics of your car or home, your choice of amplification, and your source material. We still believe that the gold standard for auditioning speakers is hearing them in your own environment — that’s why we offer a 60-day money-back guarantee.

Wiring subwoofers — what's all this about ohms? (46)

Our Listening Kit

To help you choose the right speakers, we recommend using Crutchfield’s SpeakerCompare Listening Kit. It includes a pair of studio-quality headphones, and a guide to getting the most out of your session, and a few other necessary items. We’ve carefully chosen the components of this kit to ensure a crystal-clear listening experience. It’s available for a nominal rental fee, and includes a $25 Crutchfield merchandise credit.

Request a kit

Rate your experience with SpeakerCompare

Thank you for your feedback!

We'd love to know what you think

Thank you for your feedback!

Wiring subwoofers — what's all this about ohms? (2024)
Top Articles
Latest Posts
Recommended Articles
Article information

Author: Horacio Brakus JD

Last Updated:

Views: 5912

Rating: 4 / 5 (71 voted)

Reviews: 94% of readers found this page helpful

Author information

Name: Horacio Brakus JD

Birthday: 1999-08-21

Address: Apt. 524 43384 Minnie Prairie, South Edda, MA 62804

Phone: +5931039998219

Job: Sales Strategist

Hobby: Sculling, Kitesurfing, Orienteering, Painting, Computer programming, Creative writing, Scuba diving

Introduction: My name is Horacio Brakus JD, I am a lively, splendid, jolly, vivacious, vast, cheerful, agreeable person who loves writing and wants to share my knowledge and understanding with you.