How do directional speakers work?
There are several ways of producing a directional effect, all of which have advantages and disadvantages.
The Audio Spotlight from Holosonic uses ultrasound to carry the beam which results in a very tight beam with a range of up to 200m. However, the frequency range is restricted to the higher levels, which means that the audio content has to be carefully chosen to get the best results.
The Dakota Audio range uses digital signal processing (DSP) which allows a much fuller sound, but with less absolute directionality than the Audio Spotlight.
The Panphonics range of Sound Shower speakers use planar wave technology which results in an aural spectrum similar to the Audio Spotlight.
Depending on your application and the levels of ambient sound in the installation space, either will work well.
More detailed explanantions of the technology is found here: