Embedded audio system in distributed acoustic sources

#This invention relates to an audio system. In one aspect, this invention relates to the conversion of otherwise non audio systems such as office furniture, walls, ceilings and floors into distributed audio sources for active noise control solutions for acoustical privacy.

#The office workspace has undergone significant changes in the last 30 years where work areas have become smaller with increasing emphasis on collaboration.

#Sound control is a vital aspect of worker efficiency. Significant effort is expended in the design of the workspace in order to control the acoustics, reducing the environmental noise that interferes with a worker's concentration. In addition, public spaces are often plagued with environmental noise. It is desirable to reduce the perception and effect of environmental noise in public areas such as airports, subways, and trains.

#In the drawings, which illustrate exemplary embodiments of the invention:

#FIG. 1 is a block diagram of the overall system of the invention.

#FIG. 2 is a view of prototypical office furniture having installed therein acoustic transducers

#Referring first to FIG. 1 the acoustic system 10 is generally described as an acoustical soundboard panel or body 120 and an acoustic momentum type transducer 100. In the preferred embodiment, said transducer 100 is in acoustic association with said soundboard 120. A power amplifier 110, and means for processing a sound signal 130, at least one input acoustic signal 408 and a power supply 106 complete the basic system 10. In the preferred embodiment, means to process is a Digital Signal Processor. The system 10 may include an active acoustic source 12 such as background music or masking noise. The acoustical soundboard 120 comprises a traditionally non acoustic body or geometric definition and is typically comprised of, but not limited to, gypsum wallboard, wood sheet goods, fiber reinforced composites, structural panels comprising of skins and core, consolidated organic fiber, paper, steel, aluminum, glass, wood, consolidated mineral fibers, plastic and other materials where the mechanical bending impedance varies from 10 to 100,000 N·m. The momentum type transducer 100 is an acoustical exciter that transforms electrical energy into mechanical displacement. The momentum type acoustic transducer 100 is in acoustic association with the acoustic soundboard 120 where the mechanical output (displacement) is input into the acoustical soundboard 120. The mounting location of the acoustic transducer 100 is non specific relative to the geometry of the acoustic soundboard 120. The power amplifier 110 is in the preferred embodiment a digital amplifier.

#In the present invention, the soundboard 120, inertial acoustic transducer 100 and the power electronics (110-130) work as a system. The soundboard 120 and acoustic transducer 100 properties are largely predetermined. Thus it is necessary to affect the overall acoustic output of the system 10 to result in a reduction of magnitude distortion. This affect is accomplished by causing preferential adaptation in the power electronics where its amplified signal is inversely distorted to improve the acoustic fidelity of the overall system.

#The proposed amplifier architecture in this invention may be configured such that the digital signal processor 130 will initialize an equalization algorithm when a microphone or other means for detecting sound is associated with said means for processing sound signal 130. Means for detecting sound 162 causes mans to process a sound signal 130 to initialize a series of test signals that can be, for example, white noise, filtered noise, MLS, swept sine or other stimulation signals. A frequency response analyzer is then utilized to compute the resulting acoustic frequency response of the system. Means to equalize 145 can equalize using conventional algorithms such as parametric, graphical or inverse Fourier Transform (F−1) filters.