“Stereoizing” Mono Files – Widen your Sound!

Today it will be very basic. The creation of a simple “wanna be stereo effect” on VO tracks. Sometimes I use this method which helps to enhance the sound of mono files. I will show you how to use this technique and explain something about the theory behind it.

 As you maybe know, I use various pre set tracks for different sound purposes f.e. filters and eq settings. I also have a track for widen my VO. Here’s a basic how to set up these tracks.

• Create two mono tracks and name them, don’t forget to route them to your VO bus if you have one.

• Pan them hard left and right.

• Add a simple delay, which is able to adjust an exact delay time, on one of these two channels. Doesn’t matter if left or right. I usually use Short Delay II, which ships with older Pro Tools versions, but for this example I will use Mod Delay III. Works the same. You can also just push one of the files slightly to the right or left.

• Set the delay time to a value between 10 and 35ms. Don’t go above. Higher delay times result in wider sound.

• Add a stereo VO file and listen to the result. The delay pulls the vo out of the middle and adds a sense of wideness. I like to use it when I want to get the attention of the listener, so for example on a station id. I often use this for layering and add filters, distortion etc…

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But why does this effect work? 

The idea behind this is obvious: A mono file is heard in the middle of two speakers, because the signal is played back with the same level at the same time. So there is no difference in parameter between the two channels and will be heard from the phantom acoustic source. If we set up a delay on one channel this difference is created and we will hear different information at the same time.
And why can’t we go above 35ms?
Here comes the so called Haas Effect into the game. This effect, discovered by Mr. Haas in 1949, has something to do with directional hearing/localization and reverberation. Roughly potted, it says that two signals which are heard between 0ms and 35ms after each other, are perceived as one. So if you go above the 35ms you will hear it as an echo and the effect will be spotted. For example the Haas Effect is also used for delay lines at concerts.
So why can’t I go below 10ms?
You can and the 10ms are only a practical value, but in my opinion you shouldn’t. Try it on your own- I think the phase correlations are too high which results in a thin, strange sound.

Of course this is not real stereo, but if you’re working in between this range the signal stays one, is spread over two speakers and will expand your signal!