How to choose and connect your subwoofer? Understanding Ohms simply
1 Ω, 2 Ω, 4 Ω, 2+2 Ω, 4+4 Ω... Don't understand what that means? This guide simply explains which subwoofer to choose and how to connect it correctly to your amplifier.
What are Ohms?
Ohms (Ω) represent the impedance
your subwoofer presents to your amplifier.
You don't need to know all the electrical formulas.
To choose your equipment, you mainly need to know
what impedance your amplifier accepts.
Never connect your amplifier
to an impedance lower than the one indicated by the manufacturer.
Example: if your amp is stable at 1 Ω minimum,
do not connect it to 0.5 Ω.
Start by looking at your amplifier
Even before choosing your subwoofer, look at your amplifier's data sheet.
You will generally find an indication such as:
This means that 1 Ω is the minimum value accepted by the amplifier.
1 Ω
2 Ω
4 Ω
0.5 Ω
0.25 Ω
or any value lower than 1 Ω
Single coil or dual coil?
It's much simpler than it seems.
Example:
4 Ω Subwoofer
It has a single 4 Ω coil.
It will therefore simply be used at 4 Ω.
Example:
2+2 Ω Subwoofer
It has two separate 2 Ω coils.
You can connect them in different ways.
Series or parallel: what's the difference?
Simply remember these two rules.
Parallel connection
Parallel allows you to lower the Ohms.
PARALLEL = OHMS GO DOWN ↓Series connection
Series connection allows you to increase the Ohms.
SERIES = OHMS GO UP ↑1 dual coil 2+2 Ω subwoofer
Your subwoofer has two 2 Ω coils.
You have two main options.
Coils in parallel
Very common for using a single 2+2 Ω DVC subwoofer on a mono amplifier stable at 1 Ω.
Coils in series
The same subwoofer can therefore also be used at 4 Ω. The amplifier will generally deliver less power than at 1 Ω.
1 dual coil 4+4 Ω subwoofer
This time, the subwoofer has two 4 Ω coils.
4 Ω + 4 Ω
Result: 2 Ω final
4 Ω + 4 Ω
Result: 8 Ω final
The most common connections
No need to do the calculations: here are the most useful configurations.
| Subwoofer | Parallel | Series |
|---|---|---|
| 1 × DVC 1+1 Ω | 0.5 Ω | 2 Ω |
| 1 × DVC 2+2 Ω | 1 Ω | 4 Ω |
| 1 × DVC 4+4 Ω | 2 Ω | 8 Ω |
| 2 × DVC 2+2 Ω | 0.5 Ω | Common option: 2 Ω series/parallel |
| 2 × DVC 4+4 Ω | 1 Ω | Common option: 4 Ω series/parallel |
Which coil configuration to choose?
Here are some very common examples to help you choose.
Amplifier stable at 1 Ω + 1 subwoofer
A very common choice:
1 × DVC 2+2 Ω
The two coils are connected in parallel.
Result: 1 Ω final.
Amplifier stable at 1 Ω + 2 subwoofers
A very common choice:
2 × DVC 4+4 Ω
With the appropriate connection:
Result: 1 Ω final.
You want 2 Ω with 1 subwoofer
You can choose, for example:
1 × DVC 4+4 Ω
Coils in parallel.
Result: 2 Ω final.
You want 2 Ω with 2 subwoofers
You can use, for example:
2 × DVC 2+2 Ω
With an appropriate series/parallel connection.
Result: 2 Ω final.
Lower Ohms doesn't necessarily mean better
Many beginners think you should always get the lowest possible impedance to get more power.
That's a mistake.
The goal is to get an impedance compatible with your amplifier and power suited to your subwoofers.
If your amplifier already delivers enough power at 2 Ω, you don't necessarily need to try to run it at 1 Ω.
What happens if the Ohms are too low?
Example:
1 Ω minimum
0.5 Ω
The amplifier can overheat,
go into protection mode, cut out at high volume
or be damaged.
An amplifier stable at 1 Ω is not automatically
stable at 0.5 Ω.
What if the Ohms are higher?
Let's take another amplifier stable at 1 Ω minimum.
Your amplifier will generally deliver less power, but using 2 Ω or 4 Ω on an amplifier stable at 1 Ω minimum is normally possible if the manufacturer provides for it.
Also look at the RMS Watts
Ohms are not enough to correctly choose your amplifier and your subwoofer.
You need to look at the power the amplifier delivers at the impedance actually used.
500 W RMS at 4 Ω
900 W RMS at 2 Ω
1500 W RMS at 1 Ω
If your final connection gives 2 Ω, it's the power at 2 Ω you need to look at.
In this example: 900 W RMS.
To put it simply
Look at the minimum impedance accepted by your amplifier.
Choose the number of subwoofers you want to install.
Choose the right coil configuration: 1+1 Ω, 2+2 Ω, 4+4 Ω, etc.
Remember: in parallel the Ohms go down, in series the Ohms go up.
Never go below the minimum impedance provided by the amplifier manufacturer.
Then check the RMS power delivered by the amplifier at this impedance.
Frequently Asked Questions
My amp is stable at 1 Ω. Can I use a subwoofer at 2 Ω?
Yes, in most cases. The amplifier will generally deliver less power than at 1 Ω, but 2 Ω is higher than its minimum load. Still, check the manufacturer's specifications.
My amp is stable at 1 Ω. Can I go down to 0.5 Ω?
No, unless the manufacturer clearly states that the amplifier is also stable at 0.5 Ω.
How many Ohms does a 2+2 Ω subwoofer give?
With a single DVC 2+2 Ω: coils in parallel give 1 Ω and coils in series give 4 Ω.
How many ohms does a 4+4 Ω subwoofer give?
With a single 4+4 Ω DVC: coils in parallel give 2 Ω and coils in series give 8 Ω.
Which subwoofer should you choose for an amp stable at 1 Ω?
It depends on the number of subwoofers. With a single subwoofer, a 2+2 Ω DVC is, for example, very convenient for getting 1 Ω. With two subwoofers, two 4+4 Ω DVCs can be wired to get a final 1 Ω.
Is it dangerous to use 4 Ω on an amp stable at 1 Ω?
Generally, no. The amplifier will simply deliver less power at 4 Ω. Always check the manufacturer's specifications.
Parallel = ohms go down. Series = ohms go up.
You don't need to know all the electrical formulas to choose your subwoofer.
Simply start by looking at your amplifier's minimum impedance, then choose the winding of your subwoofer or subwoofers allowing you to get the right final impedance.
Don't know which winding to choose?
You have an amplifier but you don't know
if you need a 1+1 Ω, 2+2 Ω or 4+4 Ω subwoofer?
Contact Sound Auto Concept with
your amplifier's model number
and the desired number of subwoofers.
We can guide you to the right wiring.
Sound Auto Concept
1 Rue de la Manufacture Semely, 34120 Pézenas
09.85.13.66.35
fabrication@soundautoconcept.com