Why Does My Mono Sound Wide?

This post should be read in conjunction with the previous one.

Last week I invited you to test your hearing and perception.

I have now posted the final sound clip on Sound Cloud.

The question was… Is this sound effect Stereo or Mono?

The answer is, it was mono.

So why were your ears telling you it was stereo?

I added a stereo element to the mono sound, filtered pink noise.

http://player.soundcloud.com/player.swf?url=http%3A%2F%2Fapi.soundcloud.com%2Ftracks%2F23107927 In The Pink by Mark Ty-Wharton

You can hear the stereo quite easily, move your head around if you can’t. If you have a MONO button press it and the sound will collapse.

When placed behind a mono sound, this sound has the effect of tricking your mind into thinking the sound coming from each speaker is different and hence thinking the sound is stereo.

It is actually an old trick with a new twist.

It is quite well known that if I take a mono sound and use a graphic EQ to create a comb filter (turn up / down frequency bands in alternate speakers) that I can simulate stereo.

Even my mum knows about that. She used to tell me “the bass is in the left speaker and the saxophone is in the right”.

But if I do that the resulting sound gets hollow and weird, especially if I am nearer one speaker than the other.

I needed another solution for some extremely realistic 3D audio that I was making.

I found that by adding noise and faking it’s stereo, I can fool the brain’s spatial decoding system into thinking something is happening that isn’t.

And if you are concerned that there is no noise in your audio to mask this process, I would go as far as to suggest that if you isolate any sound recorded in the real world, there will be noise in the background of it.

There will be a level where you can use this and nobody will notice. And in my experience adding a little noise can actually work really well on quiet sounds and often makes them sound a lot more natural.

Here is a screen shot from the DAW session.

The left speaker’s faders are gray, the right speaker’s faders are orange. It is really easy to see the separation.

You can download this AU plug-in free from http://www.voxengo.com/product/marvelgeq

What surprised me the most was, the sound itself can be mono, so it seems it is that ever important background of noise that gives us human beings our spatial awareness.

So there you are, I discovered something really interesting about sound and how we perceive space and I wanted to share it with you.

Feel free to download the audio from SoundCloud to put in your DAW and play with.

Anurajyati (be in love!)

Mark Ty-Wharton

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