Abstract: An acoustical enclosure for isolating high-frequency noise produced by automatic business machines, such as typewriters and teletypes. A top paper-feed housing is removable and a midsection is hinged to permit access to the enclosed machine. An exhaust fan removes heated air from the enclosure and an air-intake lip at the front of the enclosure permits ambient-temperature air to be taken into the enclosure.

Abstract: A self-contained sound masking package including a housing having an interior forming a loudspeaker enclosure in the bottom of which is disposed an electric circuit arranged to be connected to an associated source of electrical power for producing a voltage having a predetermined frequency range within the audible spectrum and with the frequencies at predetermined relative decibel levels, the voltage being applied to a transducer such as a loudspeaker having a coil supported in the housing interior adjacent the top of the housing for introducing an audible sound of the predetermined frequency range and decibel levels into the area surrounding the housing, together with means for connecting a remote signal source to the circuit to provide a supplementary audible output from the loudspeaker into the area and the electric circuit being preferably in the form of a printed circuit board and having filter means which may be selectively activated to provide an audible output from the loudspeaker throughout at least