I have a problem, maybe not the right forum but I try to ask here
my neighbour is able to to hear very quiet sounds (like breathing) through a drywall between us. I know because he does not keep it secret and makes a "counter noise" each time, some kind of stalking.
So I'm very interested in what he uses. I've tried an el. stethoscope once on a drywall and realized that's not possible with it, you would hear clear spoken conversations but not more, instead loud noise from the whole house eg water pipes.
So the drywall is thin, even without auxiliary means I can hear single loud spoken words on the phone when I'm 3 metres away from the wall and my neighbour uses the phone near the wall, maybe 2 metres away. I can also roughly locate him left and right when he makes louder noises eg. when he tidies up.
The sound might also travel partly through or underneath the two doors which are not on that wall.
So my question is: Apart from bugs in the same room, can a parabolic mic achieve that (ie hearing you breathing or very quietly moving on a sofa)? Usually you are told that you need a sight line for parabolic mics to work but how is that with the mentioned thin wall?
If one can listen up to 100 metres outside with a parabolic mic, I imagine it's possible for a few metres inside, with a wall, but also without any wind noise, I have no idea.
Any help of anyone who has used a parabolic mic would be greatly appreciated.
(if you don't have a drywall, can you hear through doors?)