Hi!
I just finished working on my Bonnaroo recordings (
https://taperssection.com/index.php?topic=192327.0) and wanted to share an insight. Most of these raw recordings sounded terribly off-center – almost unlistenable on headphones. I’d run into this issue in the past and have tried to correct it with a combination of boosting one channel and EQ’ing the channels separately. This time, it was unfixable.
Earlier in this thread, Gutbucket gave the solution to fixing this issue in the field when he said “rotate the array away from the visual center and towards the closer side of the stage / closer PA speaker”. But what about fixing it in post? It turns out that adding a small delay in one of the channels miraculously moves the soundstage to the center!
The two other factors that can cause recordings to sound off-center (as mentioned earlier in this thread) are EQ and balance. I adjust EQ, balance, and timing as follows:
First, split the channels and adjust the EQ of one channel to match the other, especially in the low frequency region. Voxengo’s free spectrum analyzer, SPAN is very useful routed as “dual mono” with “right underlay”.
https://www.voxengo.com/product/span/.
Then carefully adjust the channel balance so they match in volume.
To adjust the timing, Voxengo’s free Sound Delay VST plugin works well in real-time
https://www.voxengo.com/product/sounddelay/. Again, select “dual mono” routing (channels do not have to be split). Then spin the “Audio Delay x0.1” dial. This dial gives you up to “a foot” of delay (1 msec) and that will probably be sufficient (unless you have really widely spaced mics…) If adding delay makes things worse, switch from Left to Right.
If you can run simultaneous VST plugins (Audacity can’t…), then Voxengo’s Correlometer
https://www.voxengo.com/product/correlometer/ is useful (aim for positive correlation across the frequency range as you dial in the delay). MAAT’s 2BusControl
https://www.maat.digital/2buscontrol/ is also handy as it has a button to “flip” left and right – your soundstage should stay centered. Use the “mono” button to reference your center.
All of these plugins are free, and they’re the ones I stumbled upon and got working. I’m sure there are dozens of others that will get you to the same endpoint.
Looking back, this was the first time I used AKG C568EB short shotguns pointed just outside the stacks and apparently, these mics made the off-center situation worse since the stereo information in each channel is not as “smeared” as it would be with the standard cardioids that I’ve used in the past.
Examples? Attached below are samples of the raw file and finished recording from Courtney Barnett’s performance.