I don’t think this is mains hum, as I’ve just installed and tried “de-hum” (a triumph in itself - the installation, I mean ).
This buzzy noise is present on this cam all the time, so I’d be very grateful for any suggestions to improve it. I’ve already done Amplification (because the owls were far too quiet) and Noise Reduction.
If you had to boost the volume enough, you may be listening to the camera cooling fan or other internal workings. The first thing I thought about when I heard it was you are listening to the noise the building or structure was making. Conduction could be sluicing noise into the camera from a cooling fan 40 feet away by conduction, not sound in the air.
There’s another killer problem with shoots like this. I would tell you to put headphones on the camera and listen live while you made changes to position, location, contact with other things, etc. You may not be able to do that because it never gets loud enough to hear it in real life.
That leaves you with the desperation method. Start a long recording. Announce the conditions and let it run for ten seconds. Change something. Like put the camera in the car and say you did that out loud. If the noise is still there, then the camera is making the noise. If the noise vanishes, then there’s something about the location or your mounting. If you have it running while you moved the camera, you might be able to hear the environment changing.
It can’t take you more than a couple of days to run it down. This is not ha, ha weird by the way. This is exactly how I found a mains hum noise in my studio. I had a bass cabinet that failed to go off when I switched it off. mmmmmmmm
I’m not a movie-maker, I’m an online raptor-watcher. This is a webcam on a Great Horned Owl’s nest on Skidaway Island, Savannah - I screen-capture it (in this case, with Bandicam) 24/7 in one-hour segments to make it manageable, and go thru checking for “events”. The area, the equipment, and the already-frail tree, were devastated by Hurricane Matthew and the stream is now “faulty”. To make matters worse, I’m having to use a weak netbook for recording this nest, due to diminishing resources
I record in mp4 because it’s the easiest to edit in my very basic editor/converter, which doesn’t do wav, I suppose I’d have to convert it in Audacity but that wouldn’t be raw any more, would it?
The notch filters did each work when I tried them individually. I thought they would be applied successively if in a list.
But you’re right : only the last one on my list is being applied.
I’m sure I’ve used a list of notch filters in the past, and all were applied, [ I did tick the box for the “Legacy” syntax ].