Patent ID: 7548854

Claim:
A method of producing masking sound within a space for masking distracting noise and providing enhanced speech privacy within the space, said method comprising the steps of: (a) providing at least one transducer arranged to project sound directly into the space; (b) determining a desired spectrum for masking sound to be produced within the space; (c) producing a first noise signal; (d) subjecting the first noise signal to a pre-filter having substantially the same spectrum as the desired spectrum determined in step (b) to produce a first masking signal; (e) amplifying the first masking signal; and (f) driving the at least one transducer with the amplified first masking signal to produce within the space a first masking sound having substantially the desired spectrum determined in step (b), wherein the desired spectrum and the spectrum of the pre-filter have consistently decreasing negative dB slopes of between −2 dB per octave and −6 dB per octave within a predetermined frequency range.