aliasing is: high frequencies masquerading as low frequencies due to undersampling

Did you know high-pitched sounds can trick your ears?

You're at a concert, and the singer's high notes sound strangely low. It's confusing and doesn't seem right.

Imagine you're drawing a smooth curve, but you only draw it in a few spots. When you try to fill in the gaps, it looks like a different shape. This happens with sound when you sample it too few times (undersampling), making high frequencies appear as low ones.

Example

At 44.1 kHz, a 20 kHz sound wave looks like a 4.1 kHz wave.

Remember this

High frequencies can masquerade as low frequencies due to undersampling.

Text adapted from Wikipedia, licensed under CC BY-SA 4.0.

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