Eli5 – Why are drums round? Is it something to do with the shape that determines the ability to hit something and get a percussive sound out of stretched materials?

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Eli5 – Why are drums round? Is it something to do with the shape that determines the ability to hit something and get a percussive sound out of stretched materials?

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Drums are round because it is easier to stretch the drum head over a round shape without collapsing the sides of the structure like a square or rectangular box would. And the head needs to be stretched in order to act like a spring and bounce back to flat after being stuck, thus creating the resonating sound with its bouncing.

A [Cajon](https://en.m.wikipedia.org/wiki/Caj%C3%B3n) is a decent instrument, but the striking ‘head’ is a thin, semi-rigid sheet, usually a plywood panel, so it doesn’t need to be stretched under tension to hold its shape.

Your premise is wrong. There ARE square drums: https://tqdrums.com/en/products/bass-drum-testa-quadra/

Having that said, we probably see many more round ones because, as mentioned before me, they are much simpler to make

My thoughts.

1. Easier to make and stretch evenly.
2. The membrane is mentioned to produce kind of a basic harmonic wave. Other formes of a drum will produce more complex sound spectrum.

On a round drumhead the stress is spread evenly when you hit it.

On a square drumhead about 70% of the stress is distributed into the corners, leading to a much weaker drum.

Since the drumhead should be round it follows that the rest of the drum tends to be round. Percussion instruments where the striking point is made out of different materials (such as laminated wood) tend to have other shapes since the stress is distributed differently in materials with a strong direction (like wood).