;)
The problem of sound pollution, the source of trouble of all kinds for discotheques, has been resolved with a revolutionary device.
In fact, in the research labs of Peecker Sound, an original system of loudspeakers in double line has been produced, which reduces radiation in the two directions. This layout of the transducers is called “Double Array” and makes it possible to have a sound beam which is very concentrated along the axis perpendicular to the plane on which the loudspeakers are situated. Placing a “Double Array” acoustic speaker above a dance floor, it is possible to reduce the sound off the floor by a minimum of 10 dB to a maximum of 20 dB. This means that, if a traditional system has a sound level of 105 dB on the dance floor and 80 dB at the outer perimeter of the dance hall, adopting a”Double Array” sound diffusion system, it can drop to as little as 60 – 70 dB.
It’s as plain as the nose on your face….
It is natural to wonder why somebody didn’t get there before. Well, for the simple reason that nobody had thought of it and then because the question was, objectively, rather complicated. The great problem for sound diffusion systems has always been to concentrate the sound where it is effectively necessary and keep it down elsewhere. Unfortunately, this wish has been hindered by the very nature of the sound waves, which tend to be quite directional at mid and high frequencies, but stay omnidirectional at low frequencies.
This explains the failure to diminish the bass notes, when trying to concentrate the sound on the dance floor with speakers up high and directed, or in the so-called “rain” layout. Nothing could be done: the low frequencies always “escaped” and still registered high decibel values even at considerable distances from the dance floor.
The situation was even worse for whoever tried to channel the sound onto the dance floor using “horns” placed in front of the speakers: the sound off the floor was reduced, but at the cost of sound quality, which proved to be terrible.
It seemed to be an insoluble problem, yet the technicians of Peecker Sound, led by Ing. Gandolfi, started from an observation: they noticed that the polar frequency diagrams of a single loudspeaker show an almost omnidirectional radiation (equal radiation in all directions) at a distance of one metre, but, when four loudspeakers were placed in line, they could obtain a considerable sound reduction on the various angles.
Increasing the number of loudspeakers, reduced the angle of sound emission even more. And if the loudspeakers were placed in a double row, that is in ” Double Array” ?
As we said, as plain as the nose…
