The Power Of (Real) Mono

You've probably heard the term "checking mono compatibility". It refers to the act of listening to your mix in mono to make sure the balance is correct, and there are no weird artifacts when the left and right channels are combined.

Even when it might seem that stereo is now used everywhere, there are still many places where your song might be reproduced in mono (like phone speakers, mall PA, or clubs), and you need to make sure your mix delivers its full power through those too.

That would be reason enough to incorporate "listening in mono" into your bag of usual techniques, but switching to mono can become a powerful tool that helps you in many other ways while mixing. Let's see some of those.

Are you listening to real mono?

But first, listening in mono does not mean summing your left and right channels and listening to the resulting signal using your TWO speakers.

If you really want to experience monoaural sound reproduction, you should use only one speaker. You can achieve this by either panning both left and right channels to full left or full right or by using a utility plugin like this free Stereo Tool by Flux.

The goal here is to listen to both left and right channels summed together, but using only one sound source. Why?

For starters, if you use two speakers, differences in the exact response of each speaker's drivers and electronics, and their position in the room, can cause some boosts and/or attenuations that will not be present when listening to only one speaker.

It is true that you'll end up hearing a signal with no stereo spread in the center point between the speakers (assuming they are correctly aligned), but this is a mono signal being reproduced by two speakers.

Also, when listening to mono using two sources, your brain is creating a "phantom" image in the middle of the monitors. This image tends to be less focused or precise than listening to the signal being created by only one source.

Try it for yourself. Play any song while listening to both L and R channels summed in mono using two speakers, and then pan both to either left or right and listen to the differences (be aware that depending on the pan law your DAW uses, you might also notice a change in level).

So how can you use mono to your advantage?

The right balance

Listening in mono is a trick some engineers use when they are unsure about the balance in levels between instruments.

Let's say you can't decide whether the snare is too loud compared to the vocals. Switch to mono and check the balance of both while listening that way. If the snare is overpowering the vocals in mono, you might want to tame its level a bit.

Of course, this applies to any instrument. Is the kick too low? Are the guitars on the sides loud enough? Switch to mono and check.

In general, when in doubt as to balances in level, it is safe to trust balance decisions done while listening to mono.

EQ separation

Clashes in EQ also tend to be more apparent while listening in mono.

Maybe you panned the piano to the right, and it seems to not compete with the vocals while in stereo, but switching to mono might reveal that some EQ moves are actually needed.

Not only that, listening in mono tends to make the decisions about EQ easier in terms of finding what areas need to be attenuated or boosted in order to make two instruments find their own space in the mix.

Of course, making ALL the instruments sit together nicely in mono is harder than doing it in stereo, but that extra work is what will make your mix sound even better in stereo.

Starting the mix in mono

That's why some engineers start every mix while listening in mono. They build the main balance and processing in mono, and only when they are happy with the result, they do switch to stereo.

Once all the instruments have their own space in mono, opening up their position in the panorama will only increase their space and separation, so that extra work at the beginning provides huge dividends.

Starting the mix in mono can provide huge dividends

If you've ever tried this, you know how good it feels to start panning instruments off the center and finding out you have a pretty solid mix already.

Also, you might find that listening in mono is less fatiguing than using two speakers, so starting the mix in mono can help in mixing longer hours every day if you need to.

New perspective

Lastly, if you've been working on your mix while in stereo, switching to mono can be helpful in providing a new perspective on the work done so far.

We've already seen how the switch to mono might reveal some problems in balances and/or EQ, but the mono version will also provide a new view on the mix that can feel both fresh and useful.

For example, you might find that the space you've created in the stereo mix is not as good and "open" in mono, maybe some delays stick out too much (or too little), some of the main instruments are not loud enough, and many other details.

Summary

• In order to experience real monophonic sound reproduction, you need to use only one sound source. You can achieve this by panning both L&R channels to one side or by using a special utility plugin in your DAW.
• There are still many places where your mix will be played in mono, like phones, PAs, and clubs, so you need to make sure your mix translates correctly in those.
• Listening in mono can be useful when deciding level balances, can reveal EQ clashes that are not apparent in stereo, and you may also find it easier to EQ this way.
• Many mixing engineers like starting a mix in mono because they find the workflow is faster in the long-run, and listening to only one speaker tends to cause less ear fatigue, so your working hours can be longer if needed.
• switching to mono can provide a fresh perspective on your mix, and might, of course, reveal some artifacts and problems like phasing, hollowed-out instruments, etc.

How About you?

Do you use monophonic listening regularly? How do you use it? Did you find this article useful? Drop us a few lines!