Phase inverted surround - calculation question

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RobC
Posts: 1833
Joined: 10 Mar 2018

13 Apr 2018

My tetris knowledge seems to clear up every brick - then I will be finally ~ ready.

Here's an interesting one:

If you invert the phase of either channel in a stereo signal, the result will be the sound appearing to come from behind, or maybe "in your skull". Here, it's a really good idea to factor in mono compatibility.

Question is: what is the most optimal stereo positioning, that doesn't cancel out too much in mono, but also doesn't lose too much of the surround effect?

The following can be flawed!!!

If in the center, the sound will totally cancel out in mono.
If hard panned, there will be no surround effect, and in mono, it will be 6 dB quieter - 50% less of the original audio level.
Panning law: if you move the sound left, the right channel decreases its audio level (so that there's no extra pressure added to the left ear). I think decreasing the right channel by 6 dB will sound like it went 50% to the left if I remember correctly.

If everything is true, when 50% to the left -> in mono, there will be the left channel plus the inverted right channel (which will cancel out 50%) added, resulting in about 25%, since both channels also get reduced by another 6 dB when summed.


EDIT: Tested it, correct!

Aaand my brain is burning here. Maybe if panned 75% to the left would be optimal, which wouldn't be too lossy, yet still had a noticeable surround effect? One thing is for sure: no matter what, the total summed signal won't be more than 50% of the original audio level with these rules.

This makes such an awful feeling in my head... Dx Somebody give me the right brick!

All in all, yes. xD Problem solved, haha.

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