Experiments with parametric and directional speaker systems have been going on since the early 1960s. Ultrasonic sound has much smaller wavelengths than regular audible sound making it much more directional than a traditional loudspeaker system.
Most speakers are designed to throw sound as far and loud as possible. Parametric speakers are more like a laser beam with the sound focused at high intensity into a relatively small area. The result is that two people can be standing only a few feet apart from each other yet only one of them will hear the directional audio waves emanating from the parametric audio source.
Parametric Speakers Have Many Uses
The affects of parametric speakers are not only a great demonstration of how sound propagates through air but also offer many useful applications. Some of the possible uses for this amazing technology are:
In areas with large groups of people such as subways, airports and other public places, it may be beneficial to have a message playing at escalator landings, door entrances and other places where only the people in that small area need to hear the announcement.
Parametric speakers like the Soundlazer have already been used in commercial advertising. A person standing under a billboard to large video screen is the only one able to hear a recorded message. The advantages to this are twofold. The ultrasonic waves, being focused will get the attention of the listener and the repeated message will not be heard by others. Patrons and store clerks that would normally be distracted by the same message repeating over and over on a daily basis will no longer be annoyed by advertising that uses parametric technology.
Security / Alarm Systems
Parametric speakers combined with high decibel sirens have been used to deter robberies and other criminal activities.
There are rumors surfacing on the web that some political candidates have used parametric arrays to beam live information directly into the ears of public speakers so that no earpiece or TelePrompTer is needed. While this hasn’t been confirmed, it does offer interesting possibilities.