Mid/Side Problem

Cubase
#1

I’m having a curious issue with an MS decoding. I did a standard mic setup with cardioid and figure-8, then copied the the f-8 audio file onto an additional track and reversed the polarity on it, panned the sides tracks hard L&R and the mid track centered. But when the mixing bus sums these signals, the right channel level ends up about 2dB hotter than the left. (The reverse polarity side track is panned to the right.) Here’s the interesting part: if I “mirror reverse” eq the side tracks, boosting on one side and cutting on the other, exactly, the mix bus channel levels start to even out–with more extreme cut/boost levels producing more evening out. This suggests to me that the mid track summing with the left, non-polarity reversed side channel is producing some phase cancellation at the mix bus stage. Is there something I’m missing in the M/S decoding process?

Thanks,
Peter

#2

What’s the Pan Law set to in Prefs?

#3

The Pan Law was set to the default -3dB. I tried equal power and the other dB settings, but with no change in the disparity of the mix channel levels.

I’ve messed around with it quite a bit now, and it’s definitely when the polarity reversed SIDE channel is added in that the mix channel levels take on that approx. 2dB difference. For example, if I feed the MID track panned C and the two SIDE tracks panned L & R with no reverse polarity applied, the mix channel levels are dead-on equal. But when I polarity-reverse either side track, the 2dB disparity appears. I use the TT Dynamic Meter plug-in, so it’s very easy to view the difference.

#4

Well, the purpose of a stereo recording is, to capture a stereo audio, which means left and right channel are usually not identical. I´d start to worry, If I had a stereophonic recording, with two identical channels

#5

maybe its a DC offset problem.
on the original file remove any DC offset and then copy the file and do all processing regarding MS decoding.
give it a try.

#6

Or the original M/S was recorded badly!