It is not a new or novel idea. I've toyed with such a parabolic microphone years ago. It is amazing the clarity of conversations it picked up across the road. Just reverse the application with the tweeter at the focal point, turn it around to project sounds far away.
Instead of a dish, one can also use a cylindrical shape parabolic reflector to project the sound energy forward as a beam. Seen below is an application of a cylindrical parabolic solar collector to heat water.
Easier to build than a dish, so this is my favorite DIY choice for a long range caller.
Scaling up its size, I believe it can handle alot more power than a 'bazooka' horn.
By sitting it on a rotating table & also tilt on the vertical axis, the combination can be automated to scan the sky in all directions - like a radar!
Of course, what is the over-powering effect of the high SPL (Sound Pressure Level) at short range?
I have thoughts about its solution too.
This is just a conceptual model.. yet to be tested and proven; one that I have been thinking for a while now. I am pretty sure it will work. The effective range is of course dependent of the applied sound power and physical laws governing sound transmission through air.
Anyone out there game enough to try? I have several more ideas in the pipe line, may sound like science fiction or could be stupid ideas to some! No rocket science actually, all based on applying existing know how.
If the reflector shape is appropriately modified, it could be used for external call sounds to provide a wider beam and reduce noise pollution to the neighborhood.. think about it!
4 comments:
hi,
using reflected s pressure your efficiency will drop.
Yes, Mike. You are correct. Of course selecting the right material can reduce the loss.
Also I have other tricks up in my sleeve too.
Entirely unnecessary in my opinion. You should not be building a Bhouse away from the natural flight path of these birds anyway. Natural flight paths rely much on the terrain and contours and the vegetation below. Best to observe closely before building.
Good point, Tuck Fook. In my case, two main nucleus are 15km & 30 km away. In between are mostly flat terrains & which are feeding grounds. From the top of my BH, I can can easily see 15km to 30 km away. That's my rational of having a "super" long range caller. I know many think I am crazy. I've did some homework and it is feasible. So I am going to build it!
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