Bundling

The term "focusing" refers to the ability of loudspeakers to concentrate certain frequencies in one direction.

A loudspeaker can bundle different frequencies to different degrees. This results in a difference in the sound perception of the individual frequencies, strongly bundled frequencies are received as direct sound, weakly bundled frequencies are radiated more spatially and therefore received as room sound.

The bundling ability changes with the frequency of the reproduced sound. As a rule, it increases with increasing frequency (decreasing wavelength).

Weak bundling leads to a broader, enveloping space perception, however, the detailed direction becomes blurred. Stronger bundling reduces the spatial impression, but allows more precise localization of the sound. [1]

Isobar representation of the bundling: Using the following plot, the bundling can be seen in terms of the loudness of a frequency at a given lateral angle. File:2Way-2SubsDirectivityHor.png