FabFilter

In the past, I have noticed a bit of unexpected behavior when using Mid/Side EQ, that has caused myself a bit of confusion. I have a feeling this is not necessarily a bug, but a misunderstanding of how this plugin works. I'll try and explain as best I can with an example.

I have white noise hard panned Left, and sent to a stereo bus. When I add an EQ to the bus, and a side EQ-band and give a little boost, I would expect everything to just get louder. The content is ALL side information so to speak, nothing is hitting both channels. What happens, is I start to see content appear in the other channel. It seems apparent that it is adding the inverse polarity to the Right channel, adding some width. However, this destroys the directionality of the sound.

This example is a very specific implementation, but I see similar effects when I am attempting to use Mid/Side EQ on busses. Is this a problem with my definition of "Side?" I feel I am missing something, and any help or resources would be greatly appreciated.

Your white noise signal, panned 100% left, is not all side information. It is all LEFT information.

Try using a goniometer/stereo meter plugin. A signal panned 100% left will apear as a diagonal line, -45 degrees off from vertical. A signal panned 100% right will also appear as a diagonal line, this time +45 degrees off from vertical. A signal with only a mid channel present, i.e. a mono signal or a stereo signal whose channels have been summed to mono, will appear as a vertical line. A signal with only a side channel present, i.e. a stereo signal whose channels have been subtracted from eachother, will appear as a horizontal line.

So, in other words, that's just how stereo works.