4 Ohm vs. 8 Ohm Speakers: Audio Impedance Explained

If you’re hunting for quality speakers, choosing between 4 Ohm vs. 8 Ohm speakers can present a dilemma because audio impedance is more than just circuitry.

Like other audio components, your home stereo and car audio speakers are part of a larger electrical circuit. They are made of several electrical components, including capacitors, resistors, conductors, voice coils, magnets, internal wiring, and much more.

When an electrical current flows through a conductor from one terminal to another, it completes an electrical circuit. If there is an audio signal, the voice coil enables moves the speaker drivers back and forth in response to the signal input, thus creating sound. However, several factors affect the quality and loudness of sound delivered by your speaker. That’s why it is important to dig deeper into 4 Ohm vs. 8 Ohm speakers characteristics, efficiency, applications, and differences to help you make an informed decision between both speakers.

What is Impedance?

To understand what audio impedance is all about, we need to go back to Ohm’s Law. This law looks deeper into the nature of the relationship between the amount of electricity flowing through an electric conductor (current), the voltage (power), and the opposition to the flow of current experienced by the speaker elements (resistance/impedance).

Impedance is a measure of the resistance to the flow of current experienced by a material when an electric current is passed through it. Many people often use the terms impedance and resistance interchangeably, but according to experts at Audio Curious, these two terms have a slight variation.

Resistance is used in reference to a direct current. For example, an electrical current from the battery experiences some electrical opposition when it travels through electrical wires to the speaker. Your multimeter will show different readings depending on the material used to make the speaker and electrical wires, the setup (parallel or series connection), the output level, and the type of amplifier or receiver, among other factors.

On the other hand, impedance refers to the same opposition to the flow of an electric current but on an alternating current. Impedance and resistance lead to a loss of energy in the form of heat. Manufacturers usually rate speakers and amplifiers/receivers in terms of “nominal impedance,” which is an average impedance at different outputs.

Although much can be said about speaker impedance, it’s still a very important factor to consider since it has a direct impact on the amplifier/receiver’s efficiency. For starters, it helps you figure out how to wire your speakers without overloading the amplifier. It also enables you to mix and match different speakers and still obtain decent sound from your system.

More About 4 Ohm vs. 8 Ohm Speakers

4 Ohms and 8 Ohm speakers are some of the most popular options today. You’ll find them on your home theater, entertainment unit, and car stereo. Although manufacturers will always have an impedance rating indicated on the product box, you should never rely on this figure alone to determine the better option between the two. Here are a few facts about 4 Ohm and 8 Ohm speakers:

4 Ohm Speakers

4 Ohm speakers are designed to work efficiently with low-voltage amplifiers. They are mostly used in car audio systems. These speakers draw more power from the amplifier/receiver than speakers with higher impedance ratings. On the downside, it’s more difficult to find the perfect 4 Ohm speakers for your amplifier.

And even if you do, your 4 Ohm speakers are more likely to hit lower volume than other speakers with a lower rating because they consume less power. But on the bright side, the low power consumption means better sound quality than lower impedance speakers, including those rated at 2 Ohms.

8 Ohm Speakers

8 Ohm speakers also fall within the most preferred speaker categories for home stereos and car audio. However, most people install these speakers in their car audio systems. 8 Ohm speakers consume less power compared to 4 Ohm speakers. They also emit less heat from the voice coil and deliver high-quality sound. In addition, these speakers get to live longer and experience very few instances of distortion provided you pair them with an excellent receiver or amplifier.

Technically speaking, a low impedance speaker consumes more power than a higher impedance speaker. The relationship between voltage, current, and resistance in an electronic circuit implies that the lower the impedance for a given voltage, the higher the current. This means that a 4 Ohm speaker siphons more power from the amplifier than the 8 Ohm speaker.

Remember, you can connect as many speakers as you want to your amplifier as long as their collective impedance doesn’t fall below that of the amplifier. It would also be best to choose your amplifier wisely. The amplifier plays an essential role in the overall performance of the entire system. If you have a top-quality amplifier, it won’t matter whether you have 4, 6, or 6 Ohm vs. 8 Ohm speakers.

4 Ohm and 8 Ohm Speaker Impedance Matching

A lot has to be taken into consideration when it comes to the overall impedance of the speakers. For instance, your amplifier has a specific rating the same way your speaker does. This means that your 4 Ohm speakers should be used with the 4 Ohm outputs on the amplifier. Similarly, your 8 Ohm speakers should work efficiently with the 8 Ohm outputs on the amplifier.

When mixing and matching different speakers, wiring affects the total load imposed on the amplifier. How you wire your speakers (in series or in parallel) imposes a bigger or smaller load on the amplifier. You must be careful because a mismatch leads to poor sound quality. It could also bring costly damage to the amplifier.

Wiring in Parallel

For starters, wiring in a parallel sequence reduces the speakers’ collective resistance. For example, when you take two 8-Ohm speakers and wire them in a parallel setup, the total load falls to 4 Ohms. Similarly, wiring two 4-Ohm speakers in parallel gives you a total impedance of 2 Ohms.

It is very easy to calculate the total load when both speakers are of the same impedance. But what if you have one or more speakers with a different rating? One way to calculate the total impedance imposed on the amplifier is by multiplying the two impedances and dividing the result by the sum of the two impedances.

Speakers wired in parallel tend to maintain the quality of sound.

Wiring in Series

Unlike parallel wiring, series wiring is much simpler. Connect the positive output on the amplifier to the positive terminal on the speaker. Next, connect the negative terminal on the speaker to the positive terminal on the next speaker. Each positive terminal goes to a negative terminal on the next speaker. Do this for all the speakers on the system and finally, hook your last negative terminal on the last speaker to the negative output of the amplifier.

When two or more speakers are wired in series, you’ll add the individual impedances to calculate the total load on the amplifier.

Speakers wired in a series struggle to produce high-quality sound. Even worse, they are not so good at maintaining sound quality. As more and more speakers are added to the system in a series connection, the total impedance rises. This affects the crossovers through what we call a “crossover shift.” A crossover shift is a situation where the crossovers allow unwanted frequencies to pass through as more and more speakers are added to the system.

Parallel and Series Combination

This method is preferred when working with multiple speakers with different impedances. Remember, you don’t want to deliver a load that’s too low since it will only overwork your amplifier and gradually lead to damage. Instead, you want to focus more on a consistent load that’s not too much for the amplifier to bear.

Say you have four speakers; A, B, C, and D. All your speakers have the same impedance rating. Start by connecting the negative terminal on speaker A to the positive terminal on speaker B. Next, connect the negative terminal on speaker C to the positive terminal on speaker D.

Take the positive terminal on speaker A and connect it to the positive terminal on speaker C. Finally, the negative terminal on speaker B goes to the negative terminal on speaker D. And there you have it!

Consider the Amplifier’s Capacity to Handle Various Loads

Your amplifier must be capable of overcoming the 4 Ohm load to deliver good quality music at high volumes. An amplifier with a higher power rating is capable of delivering more power to the speaker with a lower rating.

High-end amplifiers usually have no issues with high and low impedance loads. However, if you only have a modest amplifier, you need to concern yourself with its capacity to handle varying loads. Otherwise, you risk frying your amplifier.

Remember, most amplifiers are not designed to handle a load above 16 Ohms or below two Ohms. When speakers are wired in series, more speakers mean more resistance. As the impedance goes up, the acoustic output goes down. Therefore, regardless of how many output channels you have on your amplifier, always keep the total resistance load for each channel below 16 Ohms.

It is also essential to calculate how much power each speaker will receive. This way, you can track the amp’s performance and spare your system from costly damage.

Final Thoughts

4 Ohms vs. 8 Ohms is an endless discussion. Many assume that a 4 Ohm speaker is better than an 8 Ohm speaker and vice versa. However, it all depends on the equipment designs, the purpose behind the particular product, your past experiences with similar speakers, and much more. On top of that, 8 Ohm and 4 Ohm speakers work differently on different amps. Consider all these factors before making your final decision.