Yeah I've noticed this a fair bit actually. Running a Zoom H1n for most of my sessions and there's definitely a pattern where you get this short crackle or burst right before anything interesting turns up on the playback. At first I put it down to interference from my phone or something mundane like that, but it kept happening even after I started leaving all devices in the car.
My current thinking - and I'm no expert so take this with a pinch of salt - is that whatever energy is involved in producing an EVP might cause some kind of electromagnetic disturbance first. Like a build-up before the actual event. A bit similar to how ley line intersections are supposed to concentrate energy in a spot, maybe the same principle applies here?
I've been recording out at a couple of old sites in Northumberland and the static bursts seem more frequent at locations where there's already some reported activity. Could be confirmation bias on my part, honestly.
Has anyone tried running a separate EMF meter alongside the recorder to see if the two correlate? I keep meaning to do it properly but haven't got round to setting that up yet. Would be curious whether the meter spikes at the same moment as the static.
What recorders are people using? Wondering if it's more noticeable on certain devices or if it's a universal thing regardless of kit.