I had this idea for a method of sound-proofing in November; time to file it and share it.
Sound proofing is difficult because the energy of the wave needs to be dissipated, and almost every surface will absorb, and so transmit sound, normally filtering this into a low frequency wave. The key to sound proofing is to reflect the sound cleanly and absorb as little as possible, such as a ceramic chamber with hard and heavy walls, which should transmit very little, but of course, this would create a lot of internal echoes.
The current methods for soundproofing a room or areas involve solid wooden boards with air gaps, often several layers, and the thicker and heavier, and more layers, as well as more isolated from anything else (as the sound will travel along anything these boards touch), the better. This can be a huge disruption to a space, perhaps 30 or 50cm deep of extra wall. I wondered if a better system could be designed.
My concept here is to use ceramic or metal tiles to reflect as much of the sound as possible. These would be small, perhaps 2cm, and angular rather than flat so that the sound is defected sideways to some degree. After considering this shape, I thought that a randomly grooved, and randomly shaped, star-cone would break up the sound best, in the way that the small and random marks in a gong or cymbal break up the sound frequencies. A wall of these would look something like a wall of barnacles.
A solid surface of these would be mounted on a sheet of rubber, ideally a very bouncy material like zectron, the substance used to make super-balls. The tiles should be able to very slightly angle upon touch; it is this loss of energy which will ultimately dissipate the sound energy. The rubber sheet would be mounted on a solid board.
It might be that the rubber is not needed and that the random geometry alone would produce better results, as the rubber would inevitably absorb some sound and therefore transmit low frequencies. A barnacle material of piezo-electric crystals on a solid wall may dissipate the energy by converting it into electricity, and a material that converts vibrations into light or other energies would be also be good to experiment with.
Two boards like this would face each other with an air gap. Any sound would inter-reflect inside this air gap, being trapped until it dissipates.
The result would look like a strange opposite to the 'egg box' echo protection found in recording studios; here the aim is maximum inter-reflection.
The shapes, thickness of the possible rubber, thickness of the board (a solid board, even metal, to aid reflection the sound should work best), and thickness of the air gap can be experimented with. It may be that the outer-facing surface, should perhaps absorb more than the 'back' surface designed to reflect it back. The principle is something like trapping light between two facing mirrors with one being semi-reflective.
