Coherence of Sound Waves: Myth or Reality?

[Glenn]

Can sound waves be created that are coherent in the same way that laser light is coherent?

I would guess not, because sound is a compression of the air in which it travels and could not be directed. Does anyone know for sure?

Thanks!

 

[8LPF16]

Glenn

Korg has a nifty new "monotone generator" (synthesizer); without the limitations of strings/or airflow, sustain is infinite. This even produces sounds above & below our range of hearing. Technically, any instrument capable of playing one note at a time is producing "coherent" vibration.

LPF

 

[turin]

Originally posted by Glenn
Can sound waves be created that are coherent in the same way that laser light is coherent?

If you hear a pure sine wave, then you are hearing coherrent sound. A pure sine wave is completely absent of timbre. From the spectra that I've seen, a flute produces the most timbre absent sound. If you remember the Atari, it has a very timbre free tone generator (not all of its sounds, but some). If you know how to use Matlab, you can write a vector whose components depend sinusoidally on the index, and then use the ?SOUND? (I think that's the command, use the help command to find out for sure) command to make your computer play it. Once you've heard a pure sine wave, the timbre is unmistakeable. The point is, any timbre in the sound is a deviation from the monochromonance. The stringed instruments have a very rich spectrum. The piano and harpsicord are exceptionally timbre rich.