Do interference effects occur for sound waves

Acoustic waves


The term "interference"

The superposition of waves is called interference. Two cases are of particular importance: constructive interference and destructive interference. In the case of constructive interference, the individual waves are amplified; in the case of destructive interference, the waves cancel each other out.

As a rule, interference phenomena can occur with all wave phenomena, i.e. not only with sound waves but also with water waves and light. In the case of sound, constructive interference leads to higher volume, destructive interference to silence.

Two source interference

In the simplest case there are only two transmitters (sources) from which waves emanate. One speaks here of two-source interference (ZQI). In the field of acoustics and sound waves, the transmitters are usually two loudspeakers from which elementary waves emanate.

To simplify matters, we want to assume that the waves under consideration are harmonic and have the same amplitude, frequency and direction of oscillation. This is fulfilled, for example, if two loudspeakers emit a tone of \ (440 \, \ rm {Hz} \).

Two important cases

Are the two loudspeakers (transmitter p1 and S.2) on a wall and are directed into the room, the loudspeakers generate two circular wave systems. The receiver E, which is somewhere in the room some distance from the transmitters, can be a microphone or your ear. The receiver registers the superposition of the two waves emanating from the loudspeakers. When the sound waves are superimposed, the following two extreme cases occur at different locations.