# The sound of a perfect square wave

1. Feb 18, 2015

### Mohd Abdullah

Hey guys,

It is stated that a 100% perfect square shaped wave have infinite odd harmonics and it is impossible to produced theoretically. But, assuming if a perfect square wave is produced, what would it sound like? I remember someone said it in Youtube it would actually sound like a clarinet instead sounding harsh and buzzy.

2. Feb 18, 2015

Staff Emeritus
It's a common alarm tone, and you can hear one yourself on the Wikipedia article on square waves.

3. Feb 18, 2015

### DrGreg

Human ears can't hear anything above about 20 kHz*, so you couldn't hear the difference between a "perfect" square wave and one with harmonics above 20 kHz removed.

*That's for healthy young ears. The limit could be much lower for older ears.

4. Feb 18, 2015

### rcgldr

In addition to the limitation of human hearing, wouldn't the air also limit the ramp rates on something close to a generated square wave?

5. Feb 18, 2015

### brainpushups

One fun thing you can try if you have access to Mathematica is to find the Fourier series for a square wave and then use the 'Play' function. You can add successive harmonics and try each one and then experience it for yourself.

6. Feb 20, 2015

### Mohd Abdullah

Thanks for the response. But recently I hear people saying that ultrasound can be heard if it is fed directly to the skull, I think it doesn't sound like any of the musical notes for example, the highest note of the piano. I think it sounds weird and unique. Thoughts?