In his last article, Ufuk Onen showed a neat trick to enable a stereo reverb to decay to mono as the reverb dies away. In this article, Ufuk shares a simple mono-compatible stereo widening trick that he uses all the time.

For years, I have been editing and mixing sound for films, documentaries, public service announcement videos, radio shows, podcasts - you name it! Especially when I am editing sound for documentaries, I get a lot of audio files, in varying qualities and formats, often digitized from old videotapes. The majority of these files sound horrible and 'dull' and are usually mono. I clean them up as best as I can and try to brighten them up a bit. Even if these processes work, the files still sound 'dull' most of the time. This is particularly true for music recordings, such as a live performance captured on an old VHS tape. I found out that a little bit of widening these mono music tracks helps to really liven them up.

A Mono Compatible Trick To Widen Mono Tracks

Here, I would like to share a simple stereo widening trick that I use all the time. Although I have been using this technique for audio post-production projects I have now started applying it in music projects.

And the best part of this trick? It is fully mono-compatible. Mono compatibility is especially critical for media productions, even in our day!

How It Works

Here is how I do it... My main DAW is Pro Tools, so I will use that to explain this technique, but, of course, you can use any DAW.

First, I create a stereo Auxiliary Input track and insert a 'multi-mono' delay plugin. I will explain below why I use a 'multi-mono' plugin.

Then I adjust the delay time to 5-15 millisecond for both the left and the right channel.

Here comes the critical part: On the plugin, I invert the phase of only one of the channels using the Phase Invert button.

For this example, I reversed the left channel phase; the right channel stayed as it was. To be able to do that, I pushed the Master Link button on the right top corner to break the link between the left and the right channel. This mode allows channels to work independently from each other. That was the reason why I used a 'multi mono' plugin in the first place.

Not all DAWs have this multi-mono plugin feature, but there are still other ways to do that. For example, in Studio One, to invert the phase of only one channel, you can insert the Mixtool plugin after the delay plugin, then push the Invert Left or the Invert Right button.

Hear It Yourself

You can compare the mono and the simulated stereo versions of the same music track in the video below. I prepared the simulated stereo version only using this simple stereo widening trick, no other plugin or processing have been added.