Virtually positioned head mounted surround sound system

• US 5,841,879 A
• Filed: 04/02/1997
• Issued: 11/24/1998
• Est. Priority Date: 11/21/1996
• Status: Expired due to Term

• Current Assignee: IMAX Corporation
• Original Assignee: Sonics Associates, Incorporated (IMAX Corporation)
• Inventors: Scofield, William Clayton, Saunders, Stevan Otha
• Primary Examiner(s): Kuntz, Curtis A.
• Assistant Examiner(s): Mei, Xu
• Application Number:
  US08/832,377
• Time in Patent Office: 601 Days
• Field of Search: 381/25, 381/74, 381/1, 381/17-18, 381/24, 381/26-28, 381/183, 381/187, 381/309-311
• US Class Current: 381/309
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10
• CPC Class Codes: H04S 1/005 For headphones
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 3/004 For headphones
• CPC Class Codes: H04S 5/00 Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation

Abstract

A sound system has a receiver (204) for receiving individual decoded speaker signals comprised of three independent speaker signals (226) for driving associated speakers (208-214) disposed in predetermined relative positions about the listener. Head mounted speakers (58, 50) are fixed in position relative to the head (26) of the listener. A virtual positioning system (264) receives and then positions the three individual decoded signals (226) from the receiver (204) relative to the listener as virtually positioned speaker signals (266) representative of the predetermined relative positions of the associated speakers. The virtually positioned speaker signals (266) are transmitted proximate to the right and left ears (66, 68) of the listener through the right and left head mounted speakers (58, 60), but are actually perceived by the listener as being at the predetermined relative positions of the three independent speaker signals and their associated speakers (208-214). A combiner (268) receives the virtually positioned speaker signals (266) from the virtual positioning system (264), and combines the virtually positioned speaker signals (266) such that all of the virtually positioned speaker signals (266) drive the right and left head mounted speakers (58, 60). A cross-over (274) extracts a predetermined portion of the speaker signals, and then a summation circuit (290) sums together the extracted portions of the speaker signals as a composite signal for output to an external speaker (296).

Claims

1. A sound system for an individual listener, comprising:

a receiver for receiving the individual decoded speaker signals for a sound system comprised or at least three independent speaker signals designed for driving associated speakers disposed in predetermined relative positions about a listener;

a head mounted speaker system having a right head mounted speaker disposed proximate to the right ear of the listener and a left head mounted speaker disposed proximate to the left ear of the listener, each of said right and left head mounted speakers fixed in position relative to the head of the listener and for all positions thereof;

a virtual positioning system for positioning each of said three independent speaker signals relative to the listener as virtually positioned speaker signals representative of the predetermined relative positions of the associated speakers such that said virtually positioned speaker signals can be transmitted proximate to the right and left ears of the listener through said right and left head mounted speakers, but are actually perceived by the listener as being at the predetermined relative positions of said three independent speaker signals and their associated speakers;

an external speaker disposable relative to the listener;

an audio signal conditioner for extracting predetermined portions of said speaker signals;

a combiner for combining non-extracted portions of said virtually positioned speaker signals such that all of said non-extracted portions of said virtually positioned speaker signals are combined to drive said right and left head mounted speakers; and

a summation circuit for summing together said extracted portions of said speaker signals as a composite signal for output to said external speaker.

2. The sound system of claim 1, wherein said audio signal conditioner is connected between said virtual positioning system and said head mounted speakers, such that said extracted portions of said speaker signals are extracted from said virtually positioned speaker signals.

3. The sound system of claim 1, and further comprising a video device for containing an encoded sound system audio track with sound speaker signals comprised of said at least three independent speaker signals encoded therein and a decoder for decoding said sound speaker signals from said audio track for input to said receiver.

4. The sound system of claim 1, wherein said extracted portions of said speaker signals comprise bass frequency signals.

5. The sound system of claim 1, wherein said right and left head mounted speakers are disposed proximate to the zygomatic arch on respective sides of the head of the listener and directed rearward toward the respective ears of the listener.

6. The sound system of claim 1, wherein said receiver is further operable to receive a center speaker signal in addition to said at least three independent speaker signals and said virtual positioning system is operable to position said center speaker signal as a virtually positioned center speaker signal such that it can be transmitted proximate the right and left ears of the listener as a virtually positioned center speaker signal through said right and left head mounted speakers, but is actually perceived by the listener as being at the intended position of said center speaker signal, and said combiner is operable to combine said virtually positioned center speaker signal with said non-extracted portions of said virtually positioned speaker signals.

7. The sound system of claim 1, wherein said receiver is further operable to receive a center speaker signal in addition to said at least three independent speaker signals, and said summation circuit is operable to combine said center speaker signal with said extracted portions of said speaker signals comprising said composite speaker signal for output to said external speaker.

8. The method of claim 7, wherein the step of extracting the predetermined portions of the speaker signals occurs after the step of virtually positioning the three independent speaker signals.

9. The method of claim 7, wherein the extracted portions of the speaker signals comprise bass frequency signals.

10. The method of claim 7, wherein the step of disposing the head mounted speaker system upon the head of the listener comprises disposing the right and left head mounted speakers proximate to the zygomatic arch on respective sides of the head of the listener and directed rearward toward the respective ears of the listener.

11. The method of claim 7, wherein:

the step of receiving the individual decoded speaker signals includes receiving a center speaker signal;

the step of virtually positioning the speaker signals includes virtually positioning the center speaker signal as a virtually positioned center speaker signal such that it can be transmitted proximate the right and left ears of the listener as a virtually positioned center speaker signal through the right and left head mounted speakers, but is actually perceived by the listener as being at the intended position of the center speaker signal; and

the step of combining the virtually positioned speaker signals includes combining the virtually positioned center speaker signal with the non-extracted portions of the virtually positioned speaker signals.

12. The method of claim 7, wherein:

the step of receiving the individual decoded speaker signals includes receiving a center speaker signal; and

the step of summing together the extracted portions of the speaker signals includes summing together the center speaker signal with the extracted portions of the speaker signals to provide the composite speaker signal for output tot he external speaker.