Hi Pitched squeal
 

Just reviewed an interview I shot recently. I don't know what caused the very high pitched sound (interference?) running under an otherwise fine audio track. I was monitoring using headphones, but it was an outdoor setting and the freq is so high I may not have been able to hear it with the background noise. Anyway, my question:

Any easy to do soloutions to fixing it in post? Cheap audio software programs to EQ out the noise? Other suggestions?

BTW re-shooting the interview is not possible.

Thanks

If it's a fixed frequency, or a pitch that has little movement, you might be able to zap it with a deep Q cut with an EQ. It will probably take several small passes to clear it.
If you have Audition or Sound Forge with Noise reduction, this will easily be nabbed and cut out cleanly. Sound Soap or Sound Soap Pro for the Mac or PC will also nail this, and Pinnacle's Clean can sometimes get this sort of noise. Sony's tool is top of the list, Audition and Sound Soap are very close behind. WAVES has a terrific plug too, just as good as Sony's, but it's twice the cost.

If it's a constant frequency or one that doesn't fluctuate too much, use a notch filter to zero in on the exact frequency and reduce its level. for example, to reduce the hum created by electrical cables, you'd first adjust the notch filter to 60hz.

If it's a changing frequency and if its low in volume, then a noise reduction filter will help.

if it's a changing frequency and high in volume, then a noise reduction filter is pretty much worthless because it'll affect the audio you want to keep. It'll make it sound hollow and metallic, as if it's coming from a tin can.

You're only viable option then will be to find out what's causing the squeal and cut it at the source.