I have just been checking a harp library that I'm using in Kontakt with a correlation meter. Some of the notes are fine and some aren't. And I can hear that those that show up negative on the meter seem weaker. I understand how to correct phase issues where the problem is consistent (e.g. a snare recorded with two mics), but can't think how to deal with a sampled stereo instrument where the phase correlation isn't consistent across multiple samples of different notes.

So far, I've considered putting the notes on two tracks and inverting the phase for one of the channels on one of the tracks, but this seems like a major pain.

Any suggestions?

EDIT: I seemed to remember having some success using M/S Eq to help with these problems before. I experimented a bit with this again. Lo and behold, when I cut Side frequencies below about 1300Hz by 10 dB the correlation was much better, but I still liked the sound of the instrument overall in both mono and stereo. Can anyone explain this for me? (I'll open a new question if that would be a better idea...)

BTW, I'm creating backing tracks that I suspect are mostly going to be listened to in mono, so that's why I'm trying to get a really good mono sound...

  • As soon as you get two notes playing together, you won't be able to fix it in the track. Can you get the individual files out & back in again without too much trouble? I don't know anything that would batch this, but IZotope RX has a one-at-a-time phase correction algorithm. [Otherwise, moan at the sampling company;)
    – Tetsujin
    Commented Apr 26, 2022 at 11:45
  • Yeah, having had issues like this before, I knew it had to be done before bouncing. I think I’m just gonna go with my original plan of putting different notes on different tracks. Commented Apr 26, 2022 at 12:24
  • BTW, if anyone is interested, I’ve noticed this problem on a few mallet instruments too. Presumably this is because the relative distance to the stereo mics changes as you move through the range. Commented Apr 26, 2022 at 12:25
  • Or simply use the left channel (or right if that sounds better).
    – ghellquist
    Commented Jun 21, 2023 at 11:56

1 Answer 1


Instead of splitting the stereo track into two mono tracks, you can insert into the stereo track a plugin that will invert one side.

Or, you can insert a stereo delay into the stereo track and add a minute amount of delay to only one side. (The delay output will be 100% wet.)

When you EQ'ed the Side channel you also introduced a phase shift with respect to the Mid channel. Along with the frequency cut, this phase shift may have contributed towards the restoration of the affected notes.

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