Musical sounds are vibrations which are strongly regular. When you hear a regular vibration, your ear detects the frequency, and you perceive this as the pitch of a musical tone.
Non-musical sounds are a complex mix of different (and changing) frequencies. Your ear still follows these vibrations, but there is no strong regularity from which you can pick up a musical tone.
Many sounds are a mixture of both, such as drums and other percussion instruments. You can usually decide which of two drums has the higher pitch, even if it might be difficult to decide exactly what that pitch is.
Most sounds have some regularity in them (even a door slamming) but not enough for your ear to detect a specific pitch.
Create Music with Songtrix
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