Thread: Why is a drum round not square?

Hey, I was asked to research this for an assignment in my Maths Class. I googled it, and advanced googled it however I only found 1 site which gave a whole array of answers and weren't all that mathematical. I was wondering if anyone could give me a mathematical answer? (That is easy to understand but not too easy (if that makes any sense).

Why is a drum round and not square?

The only thing I can think of is something to do with the resonance of the sound and being lost in the corners of the drum and the round shape creating a more even 'surface' for the sound to reverberate from. ???

If anybody could help me out I would very much appreciate it, thanks.

My guess is that it would be difficult to keep tension even across a square drum. It's the same principle as a table with three legs, versus four, five, six, etc. The more legs the more stable and even. A drum with 4 sides would have more uneven tension than one with 5, 6, 7, 10, 100... eventually as a shape has more sides (approaching infinity) it just becomes a circle, right?

Also, on the inside you would have two opposing faces that could reflect waves back against each other, causing distorted sound.

Just a guess, but that's my theory.

I think that as the drum is round and it's edges are equidistant from the centre i.e radius is constant. If we hit at the centre the waves are produced and will reflect from the boundary of the drum and again all waves meet constructively and hence producing a rythimic sound. Where as in non circular figure waves would not be reflected evenly at the edges and there would be both constructive and destructive interference and thus producing a sound which is not in rythm.

Originally Posted by Astar

Hey, I was asked to research this for an assignment in my Maths Class. I googled it, and advanced googled it however I only found 1 site which gave a whole array of answers and weren't all that mathematical. I was wondering if anyone could give me a mathematical answer? (That is easy to understand but not too easy (if that makes any sense).

Why is a drum round and not square?

The only thing I can think of is something to do with the resonance of the sound and being lost in the corners of the drum and the round shape creating a more even 'surface' for the sound to reverberate from. ???

If anybody could help me out I would very much appreciate it, thanks.

1. Google for Ernst Chladni

2. Have a look here: WasserKlangBilder, Klangfiguren, A. Lauterwasser, Klangwellen, Überlingen You can switch to an English version.

Thanks for all the help, this will definitely help me.