Running 8-Ohm Amp or Receiver to 6-Ohm Speakers
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Poor impedance matching between your receiver-or-amplifier and your speakers can result in excessive clipping and damage your entire audio system.

Sometimes, if you want to get quality sound, it may force you to keep the volume extremely low. However, in some cases, you simply dot have the perfectly matched equipment.

For example, what should you do if you have a 8 ohm amp or receiver but only 6 ohm speakers? Is it safe to run an 8-ohm amp/receiver to 6-ohm speakers?

It is generally OK to run 6 ohm speakers in series with 8 ohm amplifiers or receivers typically because 8 ohm isn’t far from 6 ohm. However, you need to be mindful and run your system too hard (don’t run it at high volumes and do not run the speakers in parallel).

In addition, you should check the amplifier or receiver ratings as some receivers and amps will pump out more power at lower speaker ohms ratings. Some receivers and amplifier allow a range of impedance, for example they may be rated at 8 ohms but allow a minimum of 6 ohms.

Quick Intro to Impedance

Impedance is the degree to which an electronic device like a speaker, amp, or receiver resists current flow. It’s measured in ohms and symbolized by the Greek letter omega (Ω).

running speakers at lower impedance

In simpler terms, impedance means that the lower your speaker’s impedance, the more power it will draw from your amp/receiver. At the same time, the higher the receiver/ amplifier’s impedance, the lower amount of power it can supply to your speakers. This is why it is OK to run 8 ohm speakers on 4 ohm amps. However, this doesn’t mean 4 ohm speakers are better than 8 ohm speakers.

With this information, it’s now much easier to see what happens when running 8-hm amp/receiver to 6-ohms speakers.

I hope you can see from the above explanation that an 8-ohm amp or receiver will typically supply slightly less power than a 6-ohm speaker will typically require. Is the inadequate supply of power harmful? 

Not necessarily, but you need to take precautions. Let’s see more about nominal impedance to answer this in detail.

Nominal Impedance

The term ‘nominal impedance’ refers to the reality that the impedance indicated on your speaker, receiver, or amp is an average.  

When your audio system is operating, its impedance changes depending on factors such as the frequencies it’s producing. Other reasons for impedance variation are:

  • Every speaker driver has a unique resonance frequency: The driver moves freely at its resonance frequency. As it moves, it creates the back electromotive force, which results in a significant increase in impedance.
  • Variation in the voice coil’s inductance: At higher frequencies, the inductance increases and may cause the impedance to go up. The opposite is true at lower frequencies.

These are the main factors, but many others that sound engineers consider before arriving at the nominal impedance you see on your electronic devices exist. Given that impedance is an average, the actual figure keeps fluctuating.

So, when we say our speakers’ impedance is 6-ohm, what do we mean?  We mean the speaker’s impedance will be able to dip below 6 ohms at some point. It can also increase to 8 ohms or more, depending on the frequencies being produced and other factors.

This means you can run your 8-ohm amp/receiver to 6-ohm speakers. Despite that the impedance difference is not ideal, it is within an acceptable range. This does not necessarily mean that 8 ohm speakers are better than 6 ohm speakers, it is matter of your equipment ratings.

It’s important to note that we are dealing with high amp/receiver impedance. This means it supplies less power than your speakers require.

Assuming that the impedance fluctuation is minimal, the argument that the current resistance difference is slight may not hold. This implies you should not run your 8-ohm amp/receiver on these speakers. That may not be true if you can properly hook up the speakers to the receiver/amp.

Best Tips to Wire 6-Ohm Speakers to 8-Ohm Amplifier/Receiver

To wire the speakers as required and get quality sound, you need to do the following.

1. Secure Modern Speakers

You need modern speakers to help you lessen the risk of using a speaker that pulls more power than you require.

Modern speakers are designed to do this because their frequency fluctuations are tighter.

So, if you go for the right speaker, you’ll still get quality sound. In addition, they have higher speaker sensitivity than the older versions. Remember, we can increase speaker impedance, as we shall see next.

2. Wire Your Speakers in Series

Remember, your chosen speaker wiring method can increase or reduce impedance.

With series wiring, you add up the impedance of your speakers. This means that if you have two 6-ohm speakers, you increase the impedance to 12 ohms. In other words, you reduce the power requirement by half.

wire speakers in parallel 6 ohm

There are instances when you can opt for parallel wiring. However, it would be best if you didn’t try this here. By wiring two speakers in parallel, you reduce the overall impedance by half. This means you double the speaker power requirement.

In our case, if we do the wiring in parallel, we reduce the impedance to 3 ohms. Here is the calculation:

Total Impedance = Product of Impedances / Sum of Impedances 

                            = 36 / 12 = 3

This means your two speakers will likely be demanding more power than your receiver or amp can supply. It can be dangerous, especially if you keep the volume high. The demand for power increases as the volume increases.

You can also run different speakers of different impedance together as well. Just make sure that the total impedance is not lower than 6 ohms in this case. So, you can run 8 ohm and say 12 ohm speakers but, it will be risky to run 6 ohm vs 8 ohm speakers and even more risky to run 8 ohm vs 4 ohm speakers in parallel. 

Just ensure you do the calculation as shown above to see exactly what you are working with.

You should avoid parallel wiring, especially if you want to get quality sound at a high volume.

Otherwise, the heat may build up and blow your speakers and receiver/amplifier. Sometimes, you may experience excessive clipping before that happens.

Check and Adjust Your Receiver Impedance Settings

Many receivers have settings that you can use to match their impedance with your 6-ohm speakers.

All you need to do is to reduce the impedance to 6 ohms. Other receivers have an allowable range of impedance, for example a receiver may be rated at 8 ohms but allow a minimum of 6 ohms.

Check this out below:

Adjust Your Receiver Impedance Settings 8 ohms 6 ohm minimum

This is option may not help you in some cases. Considering that the figures we are talking about here are nominal values, changing your receiver’s setting manually may reduce the system’s overall performance. This usually happens if you choose lower impedance settings.

When appropriate, you can go with higher impedance settings and get better sound quality.

Overall, using the impedance settings limits the receiver’s ability to assign the most suitable impedance at different times.

Why Does Power Capability Matter?

When talking about impedance, we can’t forget about current and power. It matters.

A proper understanding of current will help you avoid spending a lot of time trying to understand the complex impedance specifications that others present.

Current is the most critical thing your amp/receiver provides and the speakers need. If your amp/receiver is a high current design delivering at least 100 watts per channel without distorting the sound, you have nothing to worry about regarding over-powering your 6-ohm speakers.

If you have a high-quality amp/receiver, it will get the required voltage from the wall outlet and feed your speakers with the necessary current. By doing this consistently, you’re guaranteed to get high-quality sound at all times.

Wrapping Up

When running an 8-ohm amp or receiver to 6-ohm speakers, you should opt for series wiring. It increases speaker overall impedance. 

More importantly, if you don’t want to get lost in the weed of impedance, remember to choose high-quality speakers and a receiver-or-amp capable of delivering the current the speakers require.