Bad Audio: What is this effect called? Why does it occur? And how can I avoid?

[Peter Groom]

have you posted a sample?
peter

Post Production Dubbing Mixer

[Mark Gibson]

For some reason I can’t upload the file, but here’s a link I think I’ve got the problem isolated down to a glitchy lavalier mic cord (to the transmitter), but I still don’t know why the problem, other than I guess wiring goes bad. Any thoughts?

[Mark Gibson]

Dang. I guess maybe it’ll have to be cut-and-paste : the URL is https://www.envisionarymedia.com/BDD.mp3

[Peter Groom]

Did you use an unbalanced cable.
Sounds like rf getting in
You’ll not get rid if it I’m afraid . It’s not vonstant but fluctuations.
You should have heard it within 1 second and acted then.
Peter

Post Production Dubbing Mixer

[Bruce Watson]

Definitely sounds like RF interference. Your mic is *never* the only wireless operating — there are cell phones everywhere (walls don’t stop them), and all kinds of electronic things are poorly behaved and generate lots of RF junk that they spread around the frequencies. Fixing it in post is difficult to impossible, because it’s being reproduced using the same audible frequencies that you are trying to capture. Removing it is like trying to remove the salt from a cake after you’ve baked it. Not hap’nin’.

To prevent in the future, always run a scan of available frequencies with your G3 receiver. There’s almost always a frequency or three that are completely open right were you are at the time. Use one of those, and monitor every second of your capture. If you hear anything like this again, stop, rescan, resync your transmitter and receiver, and proceed. It’s the price you pay for wireless I’m afraid.

Of course, if you can, use wires instead of radios. It’s nearly impossible to have this problem with balanced XLR cables running from a wired lav to your mixer, and your sound quality will be a bit better as a bonus.