Electrical audio signal processing systems and devices – Binaural and stereophonic – Pseudo stereophonic
Reexamination Certificate
1997-05-19
2001-05-22
Harvey, Minsun Oh (Department: 2747)
Electrical audio signal processing systems and devices
Binaural and stereophonic
Pseudo stereophonic
C381S019000
Reexamination Certificate
active
06236730
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to a sound enhancing system and more particularly to a system and method for providing full sound image coverage when a listener has less than the full compliment of speakers required to hear all of the available sound.
BACKGROUND OF THE INVENTION
There are sound systems available which provide a listener with a full sound experience such that the reproduced sound appears to come to the listener as though it were being played “live” in the presence of the listener.
The DOLBY (a trademark of Dolby Labs) surround systems are typical of such systems where a listener can enjoy a full range of sound spread out in a three dimensional pattern around the listener. One major drawback to such systems is that they require more than the traditional two (left and right) speakers. Typically, these systems require at least three (the third being a center speaker for speech and other “centered” sounds) and usually also require two rear speakers. For maximum enjoyment at least one sub-woofer is also required so that the listener can hear and perhaps even feel sounds in the range from 100 Hz and below. In addition, most existing surround systems provide the same sound to both rear speakers. An example of a system in which the rear speakers have the same sound signals is Dolby ProLogic.
New systems are coming on the market whereby an improvement has been made in that the rear speakers actually receive different sound signals thereby creating a left and right effect to the rear of the listener. An example of a prior art system in which the rear speakers have different sound signals is Dolby Digital (AC3).
The above-described systems assume a very import parameter that simply is not true in most situations. The assumption is that listeners of the sound system will have the five (or more) speakers necessary to take advantage of the full range of the sound systems. Most people simply can not afford to, or choose not to, install in their listening area the number (and quality) of speakers necessary for enjoyment of these full sound systems. Also, most people have more than one location from which they wish to listen to music, the TV, etc., and the need for five (or more) speakers limits their listening options considerably.
Furthermore, computer enthusiasts are precluded from taking advantage of the surround sound systems described above where use of more than two speakers is awkward.
Accordingly, a need exists in the art for a system which can accept the five sound signal inputs (left front, right front, center front, left rear and right rear) for a surround sound system and to convert those signal inputs for presentation to left and right front speakers while still maintaining the full sound experience for the listener.
A further need exists in the art for such a system in which the sound signal inputs for the rear speakers can be either the same or different for each speaker.
SUMMARY OF THE INVENTION
These and other objects and features of our invention are achieved by a system and method whereby in a first embodiment the five sound signal inputs from a full sound system (left front, right front, center, left rear, right rear) are converted to sound signals for presentation to left and right front speakers while preserving for the listener the perception that the sound is coming from fully around the listener. The system is designed such that speech and other front center speaker sounds still are perceived as coming from the center front while sounds which would be directed to the left and right rear speakers appear to the listener as coming from the same area as the “missing” rear speakers.
In an alternate embodiment, we have designed a system and method which will accept five sound signal inputs where the rear sound signals can be identical for both rear speakers or can be different for the two rear speakers.
In a second alternate embodiment, we have designed a system and method which will accept the five sound signal inputs and expand the sound from the front and rear pairs of speakers so that the sound appears to a listener to be coming from locations beyond the physical boundaries of the rive speakers.
The embodiments discussed above take advantage of sound expansion techniques known in the art and on techniques based on copending patent application entitled METHOD AND SYSTEM FOR SOUND EXPANSION. The prior art techniques for sound positioning are disclosed in U.S. Pat. Nos. 5,105,462 and 5,208,860 issued to Lowe et al. on Apr. 14, 1992, and May 4, 1993, respectively, which are hereby incorporated by reference herein, and which are illustrations of systems for positioning sound images at any desired location around a listener. The Lowe patents take a monaural sound image input and position that sound image at a selected location. The systems discussed in the above-identified patents is herein referred to as the Q1 system.
Techniques for stereo expansion are disclosed in U.S. Pat. No. 5,440,638 issued to Lowe et al. on Aug. 8, 1995 and incorporated by reference herein. The system discussed in the above identified patent is herein referred to as the QX system.
Thus, it is one technical advantage of our system and method that a five input sound signal system can be processed in a manner that will allow the sound to be expanded so that it will appear to a listener as though it emanates from five speakers while only two speakers are used.
It is a further technical advantage that the system will operate properly in situations where the sound signal inputs which would be directed to the two rear speakers have the same content and when they have different content.
It is a still further technical advantage of our system that it can be used in situations where the listener has five speakers placed around a listening area or when the listener has only two speakers and the sound input for the rear speakers is monaural or stereo.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
REFERENCES:
patent: 5436975 (1995-07-01), Lowe
patent: 5546465 (1996-08-01), Kim
patent: 5610985 (1997-03-01), Ten Kate
patent: 5822438 (1998-10-01), Sekine
patent: 5857026 (1999-01-01), Scheiber
patent: 13002 (1975-02-01), None
patent: 116202 (1977-09-01), None
patent: 42495 (1981-04-01), None
patent: 70100 (1984-04-01), None
patent: 9212 (1985-01-01), None
Arthur John
Cashion Terry K.
Cowieson Brian
Williams Simon
Fulbright & Jaworski L.L.P.
Harvey Minsun Oh
QSound Labs, Inc.
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