The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 23, 1988
Filed:
Feb. 14, 1986
David S Hall, Palo Alto, CA (US);
Velodyne Acoustics, Inc., Santa Clara, CA (US);
Abstract
Improvements in a moving-coil loudspeaker system of the type incorporating motional feedback. An accelerometer mounted on the loudspeaker coil to develop the feedback signal is enclosed within an air-tight shield can to avoid low-frequency instability. High-frequency stability is enhanced by various means including use of a 'trumpet' shaped speaker cone, an inverted (concave) dust cap, and theta-dependent cone variations such as providing clusters of holes through the speaker cone to alter the propagation of sound waves radially in selected sectors of the cone. Also disclosed is the use of weights placed on the loudspeaker coil in selected locations circumferentially with respect to the accelerometer to minimize instability effects.