We honestly wanted to say “the easiest way to convert an 8-ohm speaker to a 4-ohm speaker is to throw your 8-ohm speaker out and buy a 4-ohm speaker.”
But we’re better than that.
This article will give you a better breakdown on how to convert 8-ohm speakers to 4 ohms than our initial thought.
THE EASIEST WAY TO DETERMINE YOUR IMPEDANCE
Getting your desired impedance the easy way takes a little math, but we promise, this type of math won’t leave you scratching your head.
There are 2 types of connections your circuit can be configured to.
Choosing the right one has caused the debate of parallel vs. series circuits.
The point of telling you this is by knowing which circuit you’re working, you can determine how much, and how to get your desired impedance.
To start, let’s talk about series circuits.
A series circuit is similar to a straight line. A series circuit has more than 1 resistor but only 1 path.
An easy way to tell if you have a series circuit is by turning a resistor off. Once you’ve turned off your resistor, does the whole circuit stop working?
If so, then you’ve got yourself a series circuit.
To find out the total impedance value of your circuit all you have to do is add up all the impedance values.
Once you know how much your impedance is worth, then you’ll know whether you need to adjust or stay where you are.
How do I determine if I have a parallel circuit?
A parallel circuit has many paths for electrons to get from one end to the other. This is the main difference between a parallel and resistor circuit which only has 1 pathway.
To figure out the impedance value of a parallel circuit you’re going to need a calculator.
The formula goes like this:
1/R = 1/R (1st speaker) + 1/R (2nd speaker)…etc.
You need to keep adding “1/R” the more speakers you have. This formula helps you determine how much impedance for a parallel circuit has.
As a reminder, the “R” in this case stands for resistance.
Now that you know the impedance levels, let’s show you how to calibrate your impedance.
HOW TO CONVERT AN 8 OHM SPEAKER TO 4 OHMS
We explained how to determine your impedance so it’s easy for you to adjust. Just like it’s easy to determine a series circuit’s impedance, it’s also easy to adjust.
The basic principle to adjust impedance is to play around with your drivers and the way they’re set up.
In a series circuit, we already know there’s only 1 pathway.
A pair of 4-ohm speakers in a series circuit equals a system impedance of 8 ohms. To convert an 8-ohm speaker to 4 ohms, all you need is to adjust what type of ohms your speakers have.
For example, if your system impedance is 8 ohms made up of a pair of 4-ohm speakers, consider taking out your 4-ohm speakers and implementing 1 4 ohm speaker.
Voila! You’ve converted an 8-ohm speaker to 4 ohms.
What’s harder is dealing with a parallel circuit.
Understanding a parallel circuit
To give you an example of how confusing this is, imagine 2 8 ohm speakers. A parallel wiring turns those 2 8 ohm speakers into a system of 4 ohms total.
A parallel wiring of 4 16 ohm speakers has a system of 4 ohms total as well.
To simplify parallel wiring, pretend your speaker system has a total of 2 speakers with 16 ohms each. What you do next is figure out how many speakers there are (2) and divide the 16 by 2.
Figuring out the total ohms for parallel wiring is taking the ohms of 1 speaker and dividing it by the total number of speakers.
The third type of wiring is a combination called series-parallel wiring.
With this type of wiring, all you have to do to figure out total impedance is figure out how much ohms 1 speaker has. Once you do that you’ll figure out total ohms for the system.
Now that you understand how to figure out how much resistance your circuit has, let’s figure out how you can either do series/parallel wiring.
But instead of jumping straight into it, we need to understand some terms.
Electrical circuit terminology
There are 2 important terms we should’ve told you earlier.
What is loading?
Think of “loading” as a storage for electrical power. In a nutshell, that’s all it is.
The second-order effects of loading are understanding what loading effects.
The 2 components it affects are voltage and current. And if you’ve been paying attention, voltage, current, and resistance are all interconnected.
To compartmentalize, there are 2 types of “phases”.
The first one we want to go over is called the “single-phase ac”. The ac, in this case, stands for alternating current. An alternating current is a current which constantly flips directions.
A single-phase delivers current and voltage every minute. In that minute, both direction and magnitude can change directly affecting current and voltage.
Likewise, a 3-phase system does the same exact thing except the timing of the delivery is more constant.
The key difference between a single-phase and 3-phase is the rate of delivery.
If you have to provide a lot of power and have a lot of speakers to power then we recommend a 3-phase system because it acts as an insurance system.
If one of the signals doesn’t pan out then you have 2 other voltage signals which cover you.
Not only is alternating current switching directions, but it also changes the direction of voltage. Again, understanding both current and voltage helps us understand resistance better which in turn helps us convert an 8-ohm speaker to 4 ohms.
We don’t want to give you extra vocab lessons but it’s necessary for preparing you for wiring.
8 OHM SPEAKER TO 4 OHMS WIRING
Obviously, there are different ways to wire a circuit.
We’ll go over all 3 so you can decide which way you want to wire.
Don’t worry, this won’t be too difficult as long as you pay attention to each detail.
Series speaker wiring
This is funny because it’s obvious, but the main component you’ll need whether you decide on series wiring or parallel wiring is speaker wire.
There are 2 options you can go with for wiring. The first is bare wire, and the other is using a protector like banana plugs.
If you use bare wires then all you need to do is connect the positive wire (red) to the positive terminal of your amplifier. For the negative wire (black), connect it to the negative terminal of your amplifier.
Another part of connecting the wire is twisting the wire to create a single strand. This makes it easier to fit into the terminal.
For those who went the extra mile and got banana plugs, insert the wire into them. Banana plugs also have markings which let you know where to put the wire.
Once you’ve inserted it, make sure the wire is spread over the plug. After that, place the cover of the banana plug over and insert it into the terminal of the amp.
Parallel speaker wiring
Parallel wiring is easy because all positive speaker leads go with other positive speaker leads and the same for negative speaker leads.
Keep in mind, adding speakers in parallel decreases overall resistance of the circuit.
If resistance decreases, then current has no opposition and that causes the amp to overload and burn out.
Otherwise, there isn’t much difference comparing parallel wiring to series wiring.
Series & parallel wiring
A series & parallel wiring is just speakers with parallel wiring configured as series speakers.
WHY CHANGE OHMS?
There are different laws when it comes to electricity which helps us understand how changing one component will change another component.
One example of this is when current meets resistance.
When current meets resistance, power is multiplied. This is the case because current times resistance equals power.
Another formula which affects power is voltage times current. Whether the voltage or current increases doesn’t matter, power increases regardless.
If you don’t remember, ohms means resistance.
If we were to manipulate the formula of current times resistance equaling power, we can divide power by current which now equals resistance.
Since we are converting an 8-ohm speaker to 4 ohms, let’s pretend the R in the equation goes down.
The only way resistance goes down is by power getting smaller, or current getting bigger.
In this case, bringing resistance down to 4 ohms will net us bigger current, or lower power.
If you lower your ohms this is what you’d get. If you were to strengthen your resistance then expect the opposite.
For your information, power is also known as watts.
But changing ohms doesn’t only affect current or power. We also have to look at amplifiers and how they relate to ohms.
WHAT’S THE RELATIONSHIP BETWEEN OHMS AND AMPLIFIERS?
The relationship between ohms and amplifiers is about balance.
The key for the amplifier is to drive a load as the same impedance with an amplifier’s output impedance.
What happens when speaker impedance is higher than an amplifier’s?
Sound quality suffers.
On the other hand, what happens when speaker impedance is lower than an amplifier’s?
The amplifier is less durable.
As you can tell by these 2 reasons, the only way for an amplifier to thrive is to have balance.
And the balance comes with impedance. To state another way, resistance from the speaker needs to match an amplifier to make sure the amplifier is at its best.
All of this balancing and figuring out how to make your speaker sound good starts with knowing how much ohms your speaker is packing.
HOW DO YOU MEASURE OHMS?
Another way ohms is represented is by this symbol:
The key tool you’ll need when measuring ohms is a multimeter.
There are 2 different type of multimeters.
The first one is digital, and the second one is analog.
If you’re using a digital multimeter then what you need to do first is set the resistance to the highest range possible. Then make the 2 probes touch each other. You’ll know it’s right if your meter displays 0 ohms of resistance.
If you’re using an analog multimeter you need to set the highest range possible for resistance.
When you put the 2 probes together then you should see the meter go all the way up. If this happens, then you did it right.
Another tool you’ll need are resistors.
Some resistors display their value by their color. An example of this is a black resistor showing the number 10.
Other resistors have no color to denote their value. Resistors with no value are marked with a +/- 20%.
The final step to measuring ohms is to connect your probes to the resistor and finding out how much resistance you have.
CAN YOU USE 8 OHM SPEAKERS ON A 4 OHM STEREO SYSTEM?
The general answer to this question is yes.
But we want you to know why.
Remember, resistance, current, and voltage working together is all about balance. Lowering speaker impedance by switching from 8 ohms to 4 ohms lowers resistance.
And lower resistance means more current which leads to potential problems like burn out.
Also, this answer depends on how many speakers you have. The more speakers mean you have to spread the power out more evenly. This could lead to worse sound quality.
The best way to find out if your stereo system can handle lowering impedance is to use a multimeter and measure the ohms before even doing anything.
If the present ohms is rated at 16 ohms, then we suggest only going as low as half of that.
For example, if the stereo system total is 16 ohms, then going to 8 ohms should be your limit.
Anything lower and you risk damage to your amplifier.