Mono Compatibility, Part 1

Today we’re talking about mono compatibility. This one is going to be super nerdy deep dive.

What is "mono compatibility"?

When audio is mono compatible, it means that your audio sounds substantially similar when played back through both a single speaker (mono), and also two speakers (stereo).

When it comes to the width of the stereo field, be careful with using only your intuition during music production.

We all want a nice expansive and wide sound, but if you only go with what sounds good to you, you can actually make your music sound worse when played back, especially if you're mixing on headphones.

This is why it's important to use proper metering and monitoring during music production, in addition to your ears and intuition.

Use both of these, not one or the other. Many old school analog recording consoles have “phase correlation meters” built right into their hardware, for this very reason.

When is audio not “mono compatible”?

Making a mix that is stretched extremely wide (i.e. not mono compatible), is when you have large amounts of important audio information panned hard left and/or hard right in the stereo field.

If you're wearing headphones, this would be when you can hear a certain part only in one ear with no (or very minimal) information in the opposite ear.

Of course, this is going to happen sometimes-feel free to use the advantages of stereo sound and move stuff around the stereo field!

But, also use moderation when doing so.

If you use lots of hard pans too often (larger than about 9-3 on the dial), and those pans contain lots of bass, low mids, or mid range information, you might start to notice the following negative effects on your music:

-Loss of 3D depth.

-Loss of the feeling of natural space and ambience.

-Phasey, tinny sounding synthesizers, especially when hard panned.

-Thinner, tinnier, inconsistent sounding vinyl pressings and cassettes. If a mix is extremely wide (out of phase), with too much bass information spread out, it can make the needle jump right out of the groove when playing back a record.

A cutting engineer will usually catch this before manufacturing starts, but it could require a remix/remaster before your vinyl could be pressed.

-Thinner sounding playback on phone and laptop speakers.

Even more reason to pay attention to mono compatibility

Instruments that are hard panned incorrectly can disappear completely when played back in mono. So, if your music is not mono compatible, it's possible that someone listening on an Amazon Echo or other small bluetooth speaker could be hearing completely different music that has missing parts.

Many smaller smart speakers and cheap phones only have a single speaker built into the hardware, so they always play back in mono, even when streaming a stereo file.

Mono compatibility is also a requirement in many traditional video broadcasting situations.

So, if you're planning on licensing your music to be used in a movie or commercial, you might be in remix and/or remaster territory if your original recordings aren't mono compatible.

We go over some practical techniques for managing mono compatibility during the mix process in our Mixing Cheat Sheet. Worth a look for all you aspiring engineers out there!

Next time in this series: how to make great mono compatible mixes, using techniques you can do at home.