You can use 4 ohm speakers with your AV receiver or modern power amp at low volumes without any issue. However, you must be careful not to accidentally overdrive your receiver or amplifier sending more power to your speakers than the receiver is capable of delivering on a continuous basis.
If you intend to run the power amp/AV receiver at high volumes for long periods, you need to match the impedance of the receiver/amp and your speakers. Otherwise, you will risk damaging your receiver or amp.
You may be asking this question because traditionally, speakers are designed to be 8 ohms. At 8 ohms, speakers provide just enough load to pull a reasonable amount of current from most receivers or power amps without damaging it.
On the other hand, at 4 ohms, a speaker may pull more current than the reciever or amp can comfortably deliver unless you get a receiver that supports 4 ohm speakers. Keep in mind as well that if two 8 ohm speakers are connected in parallel, the resulting impedance will be 4 ohms.
However, there are more factors to consider regarding this and we discuss these factors below.
What is Speaker Impedance?
Firstly, we need to understand speaker impedance What does ‘4 ohms’ really mean? This is a common question that many people who want to match their speakers and amplifiers or receivers for the first time struggle to understand.
Nonetheless, speaker impedance simply refers to how much the speaker resists current. The lower the impedance of a speaker, the more power the speaker will draw from your receiver or amp.
This is why a 4 ohm speaker is considered more “power hungry” and will demand more power from your amp or reciever more than a 6 ohm or 8 ohm speaker. In other words, if a speaker presents a 4 ohm load, it needs twice the current as compared to a 8 ohm load.
Some individuals use impedance and resistance interchangeably, but that is not quite right. We use ‘resistance’ to refer to the difficulty of sending electronic signals when a circuit uses direct current (DC). On the other hand, we use ‘impedance’ when a circuit uses an alternating current (AC).
Both impedance and resistance are measured in ohms (Ω).
When Can You Use 4 Ohm Speakers with AV Receiver or Power Amp?
4 ohm speakers are very common in home theater systems as well as 6 ohm or 8 ohm speakers.
It is important to note that the impendence of speakers is usually indicated as an average figure.
So, if you buy a home theatre speaker with an impendence of 4 ohm, the actual impendence will be slightly higher or lower than the stated figure due to the speaker’s reactance.
Reactance refers to the opposition of a speaker to an electrical current. It is similar to impedance but takes into account opposing forces and frequency.
This means a speaker rated at 4 ohms can vary from 4 to 12 ohm, depending on the frequency at which you measure the resistance. Additionally, a speaker rated at 8 ohms may actually vary from 5 to 20 Ω.
Now, most but not all AV receivers on the consumer market will tend to work with speakers within the 6 to 16-ohm range. In this case, if you are using a lower impedance speaker, a separate amp is often recommended to avoid overheating the receiver.
This means the impedance of your 4-ohm speakers can often match with your power amp/receiver if the actual impedance does not dip too below 4 ohms. In general, you will find that receivers and amps are designed to function with a wide variety of loudspeakers.
Volume Setting When Using 4 Ohm Speakers with AV Receiver or Power Amp?
So of course, the higher you turn up the volume, the more power your 4 ohm speaker will demand. The more power it demands, the more electrical current it will pull.
Since 4 ohm speakers naturally pull more current, you need to be careful when turning up the volume because it is easier to overdrive or “clip” an amplifier with 4 ohm speakers than with speakers with a rating of say 6-16 ohms.
What Can Happen if you Turn Up the Volume Louder Than Recommended?
If you turn up the volume incredibly loud, as long as you have a modern receiver or amp, it will shut down.
These devices are designed with protection circuitry to respond quickly and prevent too much damage. With a receiver, the device will shut down and you will see a red blinking light on the Standby indicator.
This is also a common reason why amps may go into protect mode when the volume is turned too high and there’s some form of electrical fault. Amplifiers often go into protection due to overdriving with low resistance speakers.
Nonetheless, you need to be careful because there are a few instances when they don’t detect the fault quickly enough and shut down after getting damaged.
Why 4 Ohm Low Impedance Speakers Can Damage Receivers or Amps
Remember, most modern amplifiers and receivers have high impendence and consume little electric energy.
If you connect a low resistance speaker to the amp or receive, this speaker will demand too much current, more than the amp or receiver is capable of handling.
Thus, the receiver or amplifier will draw more power than it is designed to deliver to meet the unusual increase in demand.
This may make the amp/receiver to overheat because much current will run through the AV receiver’s output transistors, causing it to shut down. This mechanism also protects the speakers from exploding.
Too much current will run through the AV receiver’s output transistors, causing the receiver to overheat and shut down.
So, even though you can use your 4-ohm speakers with your receiver or power amp, you must do due diligence by keeping the volume low.
If that is not the kind of music that can suit your needs, you must learn to match your speaker’s and power amps/receivers’ impendence as we explained.
How to Match the Your Speakers and Amp/Receivers’ Impedance
We hope you understand the risks involved when hooking up a 4 ohm speaker to your receiver or amp. So, one of the most important things you need to do is to match your receiver or amplifier impedance to your speaker impedance.
The fact is that low 4 ohm impedance speakers need a powerful amp because they pull a lot of current.
This can make them quite a headache to match with a modern AV receiver. You need to do before making your buying decision is to check the impedance range on the amp/receiver’s specification.
If the stated impedance is between 4 and 8 ohms, it is best to go for a receiver or amp to handle the common impendence rating for home theatre speakers, which is 4, 6, and 8 ohms.
If the amplifier/receiver’s impedance ranges between 6 and 8 ohms, you need a 6 to 8 ohm speaker.
In the case of say 4 to 6 ohms, you can still use it with your 4-ohm speaker, but you need to keep the volume low to avoid damaging your receiver or amp. You don’t want to overload the power supply or damage your speaker.
If the indicated power rating is 8 ohm, we wouldn’t risk it. It’s better to get the 8 ohm-speakers and not 4 ohm speakers in this case. However, if you choose to, just remember to keep the volume low.
What If The Speaker Impedance is A Static 4 Ohms or Lower?
We have seen that you can use your 4-ohm home theatre speaker with amplifiers and amps that are designed to drive the lower-impedance speaker. You may be asking whether there is something that you can do when the speakers’ impedance remains static at 4 ohm or drops.
If that is the case, let us start by considering that:
If the impendence reduces, your speaker will have a lower resistance to electric signals, meaning it will consume much more power than 4-ohm speakers. However, it will still have a lower average resistance than 8-ohm speakers and others with higher impedance.
So, if you have a power amp/receiver, the connected impedance load will determine whether you can use the speaker with it.
The listed impendence refers to the optimum speaker impedance that the amplifier or receiver can comfortably drive.
In other words, if the reciever or amp lists 4 ohms, you can connect your 4-ohm speaker to the amp and get some quality sound. However, if the speaker’s resistance is even lower than 4 ohms, the sound system may still work seamlessly and meet your needs as long as you keep the volume low.
Can You Change the Impedance Settings of Your AV Receiver?
If you have a modern AV receiver, you can use the settings feature in the setup menu to change the impedance setting, depending on your needs.
The idea is that if you are using a 4-ohm speaker, you can adjust the setting to 4-ohms and get the desired sound quality without putting your devices at risk.
However, many audiophiles will tell you that you should leave the impedance setting at 8-ohms, which is the default. This is because changing the impedance setting on the receiver can distort signals and damage the speakers.
Best AV Receivers For 4 Ohm Speakers
In general, AV receivers from Onkyo and Yamaha tend to be rated for 4 ohm speakers. The Onkyo TX-NR616 and Yamaha RX-V773 are two great examples. In terms of amps, the Pyle PD1000BA is a good choice.
To use your 4 ohm-speakers with an AV receiver or power amp, you should keep the volume as low as possible to prevent damaging your receiver or amp. You should also get a reciever that supports 4 ohm speakers.
However, you are assured of the best experience and can increase volume as you want if you properly match the impedance of the speakers and your AV receiver/power amplifier.
Most AV receivers are rated to deliver power to speaker systems with an impedance of 6 ohms to 16 ohms.