Two Speaker Interference, 3B55.10

Topic and Concept:

• Wave Motion, 3B55. Interference and Diffraction of Sound

pira200 Listed

Location:

• Cabinet: Waves and Sound (WS)

• Bay: (A1 Right)

• Shelf: T

Abstract:

Two speakers driven from a common source are mounted at the ends of a 1 m rotatable bar.

Important Setup Notes:

• N/A

Setup and Procedure:

1. Place stand on tabletop.
2. Using a right-angle bracket, connect the 1 m bar with mounted speakers at the center to the stand.
3. Plug in the function generator nearby.
4. Connect the speakers to the function generator using BNC cables. Only one speaker needs to be connected (the two are connected internally).
5. Choose a function (sine works well) and frequency.
6. You can move locations of constructive and destructive interference by rotating the 1 m (need to loosen right-angle clamp first).

Cautions, Warnings, or Safety Concerns:

• N/A

Discussion:

Sound waves obey the principle of superposition. When two sound (pressure) waves encounter one another, they interfere. Spatially, the resultant wave has alternating spots of constructive and destructive interference.

Videos:

• Lecture Demonstration's Youtube Channel

References:

• Wikipedia - Interference

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