I don't think this has been posted before, if so I'm sorry to repeat it.
I think it fits perfectly into the " unusual " category , what else can you call a painting that radiates sound ?
Sound planes were invented here in Argentina, then the inventor sold his patent, but the technology was not fully exploited. Perhaps it was one of those cases in which you buy to leave a product in oblivion, eliminating a competitor? I have items from those years in some corner of the house, I'll see if I can find them.
I advance what the Wiki says :
" Sound plane (speaker)
The sound plane is a type of high power speaker (from 60 to 100 W per channel) whose main characteristic is its small size compared to boxes or baffles capable of delivering the same power. The speaker is essentially a panel of rigid plastic foam, not housed in any enclosure but simply placed in a frame, like a painting. The foam panel is moved by means of a device called an "acoustic hammer". The speakers manufactured in Argentina were marketed with a decorative cloth and a frame with the idea of hanging them on the wall. This makes its main difference with the boxes with common speakers, the sound plane is compact and lightweight. It was invented by the Argentine Juan Bertagni in 1970 who came to market some models in his country, but in 1975 he moved to the United States to continue producing his invention.1
Traditional speakers are mounted in a large box to produce the lowest sounds. The problem with such a cabinet is that it does not allow free propagation of sound, thus making fully omnidirectional sound (in all directions, ie 360°) impossible. Instead, the sound plane is essentially a panel of rigid plastic foam, which is not housed in any enclosure, but simply placed within a frame, like a painting. The frame could measure 24 inches high by 15 inches wide with a thickness of no more than 5 inches, framed in simulated oak or walnut. The foam panel is moved by means of a device called an "acoustic hammer" by Bertagni. By modifying certain features of this hammer, as well as cutting grooves in the back of the panel, BES (Bertagni's company) achieved better frequency response in their loudspeakers. The sound plane by doing without a speaker makes its design much more compact, in fact the first copies made in Argentina came with a decorative image with the idea of hanging the speaker on the wall, like a painting. In a 1985 New York Times publication, he notes that the "BES SM-80 uses novel methods to achieve a happy combination of low price and high performance." In 1982 the Bertagni company introduced the $400 SM-100. dollars a pair, with "omnipolar" sound dispersion, meaning the same from any position in a room. The new low-priced Bose model mentioned above uses a multi-directional array of drivers to recreate a balance of reflected and direct sound energy. A fin or "direct power control" changes the radiation pattern of the tweeter. Bose also has an updated version of their 501 model, a $680-per-pair system in a floor-standing cabinet.3
Currently Live Wall continues to sell the product.4 "
DOS PLANOS SONOROS MARCA BERTAGNI 60W . SE PUEDEN COLGAR EN LA PARED. MEDIDAS: 80x60x10 CMPOR SER UN PRODUCTO MUY FRÁGIL NO HAGO ENVIOS
articulo.mercadolibre.com.ar
/)
es.wikipedia.org
www.larsenhifi.com
