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Fixing an off-center recording

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WiFiJeff:
A friend recently sent me a file of a nice piano recital he taped from the extreme right side of the house, with the sound quite definitely coming from the left side of the headphones.  The average volume for the left and right track is quite close, in fact the right channel measures marginally louder.  Clearly there must be timing issues here as well accounting for the perceived placement of the piano off to the left (which it was).  Is there any suggested delay that might correct this, has anyone successfully tried this?

Gutbucket:
Likely just a millisecond or two, but whatever works.  Will need to listen and adjust for best effect.  Good technique to try 1st.

Alternately, I made some stereo recordings nicely listenable that were very annoyingly "everything of interest over to one side" by treating them as Mid/Side.  Assign the the channel with the stronger primary content as Mid and the other channel as Side.  Dial in ratio to taste.  Places the primary content channel dead center and splits the other channel out to either side.  Centers the off center content while preserving stereo room reverb.  The biggest potential problem is it can cause deep bass to skew left due to the right channel receiving the polarity inverted side channel.  However, that might not be a problem with solo piano, or an ensemble that doesn't have heavy deep bass content.

boomfizzle:
I've used Gutbucket's suggestion for M/S in the past on recordings with problematic stereo images to great success, but before I go that far these days, I usually start with Izotope RX's Azimuth module. The Suggest button usually does a great job matching level (left side of module) and if I know I'm feeding it an off-center image, I'm more likely to let it suggest a delay (right side of module) as well.   If your fileset is broken into chunks, feed it your most consistent chunk and use those same suggested levels on all the fileset chunks. 
I never use Adaptive matching on the level side because the artifacts seemed weird to me on previous attempts.  I never use Adaptive delay unless the mic stand was really swaying during the show or something.   YMMV but it might be worth a render to hear for yourself. 

voltronic:
Another thing you can try is to delete the first few samples from the left channel and shift it to line up the start with the right. Yes, this amounts to a delay, but now you're working at the sample level rather than the millisecond level. It may be just enough.

WiFiJeff:
Thanks for the suggestions.  I ended up going with a 7ms delay to the left channel, which may have been overkill but I liked the centering this produced.  While fooling around I noticed that generally with centered piano recordings I was seeing a consistently louder right channel, which given that the sound is coming more from the open body off rightish and not the keyboard on the left is reasonable.  Raising the right channel by the observed 2.5 dB I measured from another centered recording did not help, however, the time delay seems to account for the perceived shift.  On speakers the whole thing is not a big deal, but on headphones (and I guess most people do a lot of listening this way, I certainly do) the difference is major.

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