If you are searching for speakers for your home theater system, you will notice that most speakers are rated between 4 and 8 ohms impedance. When we talk about a speaker’s impedance we are talking about its electrical resistivity or its resistance to electrical current.
So, are 4 ohms speakers better than 8 ohm speakers? A 4 ohm speaker will demand more power from your amplifier than an 8-ohm speaker to produce the same sound volume. This is because speakers of lower impedance will pull more current. This can be explained by ohms law which states that for a given voltage, a lower impedance will pull more current and so consume more power. This means a 4 ohm speaker will offer good sound quality once you have a powerful amplifier.
Speakers come in a wide variety of impedance ratings, and matching your speakers’ and amp’s impedance ensures that your audio and video systems produce better sound quality.
However, on whether 4-ohm speakers sound better than 8-ohm speakers, there is no direct answer, so before answering it, we need to consider how impedance impacts efficiency and sound quality.
Quick Intro to Speaker Impedance
Speaker impedance refers to the resistance that speakers offer to the electric signals that amplifiers supply.
Note that an amp’s output current is AC, meaning speaker impedance is the combination of AC reactance and DC resistance.
To put it simply, a speaker’s impedance is the force that affects how the speaker draws electric current from the amp/ receiver.
Impedance is measured in ohm, and it uses the Omega symbol (Ω). Unlike resistance, which is measures on ohm as well, it changes with frequency.
As a result, manufacturers always indicate the nominal impedance of speakers. In other words, the figures you see on speakers are the average of their lowest impedance.
Why Does Speaker Impedance Matter?
Speaker impedance determines the type and size of the amp that you can use. So, before connecting an amp to speakers, you must verify their impedance.
Most current Hi-Fi amplifiers are designed for 4 to 16 ohm speakers. This range shows that they allow a minimum of 4 ohms. Therefore, for your amp to be happy, you need to supply it with a speaker rated 4Ω, 6Ω, 8Ωm, or 16Ω depending on where it is rated within that range.
It is important to note that the higher the impedance, the lower the electric signals flowing through the speaker, and the lower the available power. The opposite is also true.
This means more current flows through 4-ohm speakers than 8-ohm speakers. Given that lower impedance speakers are more power-hungry, they cannot give you the best output if you fail to meet their high energy demands.
So, can you use 4 ohm speakers with your power amplifier? Yes, if the amp can provide the power that the speaker will require. Some amps will specify different power outputs for 8 ohm and 4 ohm speakers. For example, the Outlaw 7125 can push 125-Watts for 8 ohm speakers and 190-Watts for four Ohms. In fact, many Emotiva and Outlaw amps have this functionality. To find out more, check out our Emotiva vs Outlaw comparison.
Speaker impedance matters more when you connect more than one speaker to an amp. Consider that if you connect four 4-ohm speakers across your amplifier in parallel, you will get a total load impedance of only 1-ohm.
So, to get the right sound quality, you may have to use a speaker selector with impedance matching or impedance protection.
Which One Guarantees Better Sound Quality, 4 Ohm vs 8 Ohm?
Using 4-ohm speakers without a compatible amp can damage the speakers. Many amps are rated 8 ohms, which cannot meet the power demands of 4 ohm speakers.
In most cases, your amp or receiver will always shut off as soon as you power it on to protect your audio system from further damage.
This is especially likely to happen when you turn up the volume too high. In this case, the amp may go into protect mode to avoid damage.
Of course, you are more highly likely to find good 8-ohm speakers than 4-ohm speakers. This means in most cases, 8 ohm setups will sound better than 4 ohm setups but this only applies if you do not have a supporting AV receiver or amp for 4 ohm speakers. The fact is, receivers that support 4 ohm speakers and amps that support 4 ohm speakers are sometimes more difficult to find than the higher impedance alternatives.
However, did you know that there are amps that give double the power for 4 ohms, depends upon the design. So, they produce 100w at 8 ohms and 200w at 4 ohms.
Even though most amps and receivers are rated 8 ohms, you can find lower impedance receivers and amps if you do some homework.
In fact, we have a list of the best modern 4 ohm certified amps and the best receivers that support 4 ohm speakers.
You can connect these to your 4 ohm speaker and 8 ohm speaker and get adequate volume and quality for your living room.
So, what is the difference in sound quality that 4-ohm and 8-ohm speakers deliver? It’s hard to say since there are many other factors to consider, like sensitivity. You cannot always consider impedance alone to judge the performance of your speakers. However, the bottom line is that there is no direct answer as to which sounds better between 4 ohm and 8 ohm speakers. This is because the issue is not so much with the speaker, but what it is connected to. If you have a powerful amplifier, you can use a 4 ohm speaker and get excellent sound quality because the speakers are power-hungry. However, if your amp is struggling to pull deliver the power the speaker demands, the sound output won’t be great. The only benefit of low impedance 4 ohm speakers is that low impedance may also help you to notice the fine-tuning that the designers do when manufacturing speakers.
Since speaker impedance changes depending on frequency, the areas of high impedance in a 4-ohm speaker can reduce your music quality if you choose a low-quality speaker.
Speaker engineers typically use electrical circuitry to flatten these areas to guarantee consistent sound throughout the audio range, but it’s not always perfect.
Is There a Clear Winner Between 4 Ohm and 8 Ohm Speakers?
We have compared the performance of 4 ohm and 8 ohm speakers. Which one of them guarantees the best sound quality?
Let’s cut some corners and quickly answer a clear winner here – it largely depends on whether your amp/receiver can drive the 4-ohm speakers properly. Remember that no home theatre system is immune to impedance issues.
As we have seen, 4-ohms speakers need amplifiers with the ability to drive the high 4-ohms load. When that happens, they give good quality sound.
This is why speaker designers and manufacturers prefer to use selective ohm resistance in their flagship or top-end models, which are often expensive.
Provided you have a high-quality amp/receiver, you can choose 4-ohms speakers whenever you want a boost in performance and natural sound. Nonetheless, an 8-ohm speaker with higher sensitivity is as effective as a 4-ohm speaker. For that matter, you can get the same quality of music with either a low or high impedance speaker provided you choose the right one and have a compatible receiver/amplifier.
As an example, the Yamaha’s RX-V673 7.2-Ch Receiver is rated at 4 ohms:
Keep in mind however that 8 ohm speakers are more sensitive than 4 ohm speakers and so offer the benefit of not fully loading the amplifier and driving the speakers with good sound levels at minimal power.
However, if you are tight on budget, it is safer to go for 8-ohm speakers so that your AV receiver is not overburdened.
Amplifier Power Based On Impedance Example
To give a clear example of how amplifier power changes with the impedance of attached speakers, let’s take the popular power amplifier Crown XLS1000 as an example.
This amp is dual channel and if we assume both are in use at the same time, the maximum power output of the amplifier changes as the speaker impedance changes in this way:
- With an 8 ohm speaker, the maximum output power will be 215 watts.
- With a 4 ohm speaker, the maximum output power will be 350 watts.
As you can see, the 4 ohm speaker will demand much more power from the amplifier. In other words:
Low impedance → more current → greater load → more power
High impedance → less current → smaller load → less power
Can an Impedance Switch Improve Sound Quality?
Some AV receivers and amplifiers feature an impedance switch that you can use to switch between ohm settings.
For example, if you have 4-ohm speakers but lack a compatible receiver, you can use the switch to eliminate the risk of damage or improve the sound quality.
However, they are not the perfect solution. The problem with using the switch is that impedance is a curve that varies. It is not a flat setting.
This means when you use it to “match” the equipment to the speakers, you intentionally cripple your receiver or amp’s full capacity. For that matter, it is much safer to leave the impedance on its highest setting and find compatible speakers for optimal performance.
In some cases, four-ohm speakers typically give better sound if connected to the right amps/receivers, but you can buy an 8-ohm speaker with higher sensitivity and get the same quality. In general, however, the most important aspect is the rating of the amp or reciever that the speakers are connected to. 4 ohm speakers will perform well with amps/receives rated for 4 ohm and the same goes for 8 ohm speakers.