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:
Dec. 06, 1994
Filed:
Jun. 01, 1993
QSound Labs, Inc., Calgary, CA;
Abstract
A system for processing an audio signal for playback over headphones in which the apparent sound source is located outside of the head of the listener processes the input signal as if it were made up of a direct wave portion, an early reflections portion, and a reverberations portion. The direct wave portion of the signal is processed in filters whose filter coefficients are chosen based upon the desired azimuth of the virtual sound source location. The early reflection portion is passed through a bank of filters connected in parallel whose coefficients are chosen based on each reflection azimuth. The outputs of these filters are passed through scalars to adjust the amplitude to simulate a desired range of the virtual sound source. The reverberation portion is processed without any sound source location information, using a random number generator, for example, and the output is attenuated in an exponential attenuator to be faded out. The outputs of the scalars and attenuators are then all summed to produce left and right headphone signals for playback over the respective headphone transducers.