Do parabolic mics work through thin walls?

[Pano]

Good point Kevin!

Anyhow, it's probably not a parabolic mic. Just a parabolic neighbor.

[Andrew Eckhardt]

Sounds like a job for a pile of bass shakers (find the studs), some 3" drywall screws, and infrasonic signal generator. Play around with it until you can get stuff to rattle on his side of the building. Whenever he gives you the "signal" you can return the favor. If the floor joists run across both rooms you can put some on there too. Or put a surface mic on the wall and send the output through a cheap delay/reverb unit to the power amp and turn up the gain just under the point of feedback. Just for fun, let it actually feed back once in a while. You could even run a line in from the bathroom. See how he appreciates that.

[trecker4]

Ok, thanks for the answers.

Maybe it depends on the actual implementation, shape of the deflector and type of (directional) microphone and amp.

the most probable alternative imo, is, he found a hole in the wall or made one and put a simple electret microphone with a wire just before the wallpaper. A cheap amp would suffice then. But a parabolic mic would be easiest because it leaves no traces plus one might get directional information (?).

White noise generator is a good idea but it will go on my nerves. I would prefer sound proofing but then again it would be useful to know what type of microphone is used because it's expensive...Until then: Hip-Hop


ps authorities won't believe you if you have no proof. They will think you're insane then which can be even further exploited by harassing neighbors. The only solutions in such a case are, if you think about it, defense (ie sound proof or moving away) or to take equal measures, that's the creepy thing.
Of course eavesdropping is a huge waste of time for everyone involved. I also suppose the person who does it gets an irrational feeling of superiority over time and can't stop it, it could be like a drug.

[dfidler]

How to Protect Your Home From Listening Devices | eHow.com

[tomtt]

Originally Posted by trecker4

My neighbour is able to to hear very quiet sounds (like breathing) through a drywall between us.

(if you don't have a drywall, can you hear through doors?)

i lived in this building for a while (the larger one) -



a stout building,

all concrete, and steel.

it's truly amazing what can be heard,

especially at night.

sometimes i'd lay in the bathtub, water covering my ears.

and just listen.

refrigerators turning on, sound much like the 8-track,

in those soundesign receivers.





at night -

[Pano]

Jeez Tom, I didn't know you were that old! Did you park your Flivver out front?

[jneutron]

Yes, a parabolic mike will indeed work through a thin wall.

A parabolic reflector is designed to take a planar wavefront and reflect it into a focal point with time coherence. If a wall is vibrating as a result of sound energy, wherever it is vibrating in a planar fashion, the reflector will work correctly.

What will be lost is the directivity information if the wall acts like a piston source. In general, it will not be possible to discern the origion point of the source on the other side of the wall. But the parabola will need to be pointed directly at the wall, as any angle will destroy the pickup ability, with hf being lost first as a result of wavelength issues.

Cheers, John

[Rembrant]

As others have previously noted, there are simple and effective ways to end your problem. My suggestion involves the early hours of the morning and a couple of packs of black cat fire crackers. If you really want to be creative, you can use a metal trash bin as the blast protection device and a sound "enhancer"..

[sergedebois]

You can get a pretty cheap contact mic with built in amplifications, like the device at Listen Through Walls Device. I have one - works great on brick and drywall.

[DF96]

Would a sufficiently thin wall act more like a planar array of sources, excited by the incoming wavefront, rather than a piston? There would be the problem of reflection, and some phase shift at the edges becuase they would be less free to move, but I would expect a parabolic system to work reasonably well. You might even be able to achieve partial cancellation of reflections by using another mike and a time delay.

You could check for a mike in the wall by using a metal detector, such as those used by electricians to stop them drilling through wires.

Just one question: you are the recipient of this unwanted attention, and not the perpetrator seeking better technology?