Understanding Ohms in Car Subwoofers: What are the Differences in Sound and Power?
When it comes to car subwoofers, one of the most important—and sometimes misunderstood—concepts is impedance , measured in Ohms (Ω) . Impedance plays a key role in the performance of your car audio system. Whether you're choosing a new subwoofer or looking to optimize your existing amp, this article will explain everything.
What is an Ohm?
The Ohm (Ω) measures the electrical resistance that a speaker (or subwoofer) opposes to the current supplied by an amplifier.
The lower the impedance, the more power the subwoofer demands from the amplifier.
The higher the impedance, the less power the subwoofer requires , but it will also be a little quieter at the same volume.
The most common impedances
In car audio, subwoofers are generally available in:
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2 Ohms
-
4 Ohms
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1 Ohm (rarer, used in SPL or for very powerful systems)
-
And sometimes in 8 Ohms , especially for home audio or certain series installations.
Some subwoofers are also dual voice coil (DVC) , which allows wiring in 1 Ohm, 2 Ohms, or 4 Ohms depending on the desired configuration.
What is the difference between 2 Ohms and 4 Ohms?
🎵 The sound
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At equal power , a 2 Ohm subwoofer will play a little louder , because it draws more power from the amp.
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However, a 4 Ohms sometimes offers a cleaner and more precise sound, especially on very deep bass, because it places less strain on the amp.
🔌 The power
Let's take an example with an amplifier that gives:
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500W RMS under 4 Ohms
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800W RMS under 2 Ohms
👉 In 2 Ohms, the subwoofer will receive more power , therefore more sound pressure (SPL) , but be careful not to overload the amplifier or undersize the subwoofer.
Should we favor 2 Ohms or 4 Ohms?
It all depends on your setup!
| Objective | Ideal impedance |
|---|---|
| More power and volume | 2 Ohms |
| Better sound quality and reliability | 4 Ohms |
| Multi-subwoofer setup | depends on the wiring, often 2 Ohms final |
| Very powerful mono amp compatibility | often 1 Ohm |
Important : Always adapt your wiring according to the capabilities of your amplifier. An amp not designed for 1 Ohm may heat up or go into protection mode.
And what about dual voice coil (DVC) subwoofers?
A 4 Ohm DVC subwoofer (dual 4 Ohm voice coil) can be wired:
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in 2 Ohms (coils in parallel)
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in 8 Ohms (coils in series)
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or used individually
This is very convenient for adapting to different amps or for mounting multiple subwoofers together.
In summary
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Ohms influence the received power and sound of the subwoofer.
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2 Ohms = more power, more volume
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4 Ohms = better control, less stress on the amp
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Always match the wiring to your amp to avoid any risk of overheating or failure.
Need help choosing the right subwoofer or amp?
At Multison , we help you find the right impedance , the best cabling , and the most suitable products for your installation, whether for SPL, SQL, or everyday pleasure.
👉 Discover our selection of subwoofers and amplifiers
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