Saturday, May 26, 2007

Acoustic labyrinth

As the name implies, a labyrinth design is intended to channel the speaker's back-wave through a series of tunnels/tubes/openings and so-forth (like a labyrinth) until practically all of the acoustic energy is absorbed. Very little sound is reflected back to the speaker and thus the system behaves like an infinite baffle.

It sounds nice in theory, but it's usually far from ideal in practice. At best, a knowledge of horn design principles can be used to design a box that absorbs energy in an effective manner. For example, one practical approach might be a spiral shaped column of air (think: sea-shell design). In the same way that horn loading increases a loudspeaker's efficiency, the same principle can be used to concentrate acoustic energy onto damping materials, thus making them more effective at absorbing energy. Anechoic chambers rely on this principle by using thin triangular wedges on the interior walls.

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