Page 9 - Vibrations

Even suns and planets have resonances.

A resonance begins with an excitation - usually a white

noise source such as an impulse.

An impulse contains all frequencies - some of these

frequencies will match the resonance frequencies and

will be excited.

If the excitation is a single impulse, the resonance will

decay - it only remains active providing energy is fed

into it.

Superposition Principle

When you have several acoustic

sources, at any point (where the

ear is) they will create single wave

front which is the sum of the

individual sources.

This can be illustrated by adding

several sine waves of different

frequencies.

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