Claims
- 1. In an apparatus for audio reproduction wherein multidirectional source signals are transmitted in two channels suitable for monaural and stereo loudspeaker presentation and having the multidirectional signals encoded in said two channels with predetermined amplitude and phase relations indicative of source directions and adapted to be decoded for formation from the signals in said two channels of more than two loudspeaker presentation signals having source signals corresponding to every source direction appearing in a plurality of such presentation signals but in differing relative amplitude, the improvement comprising
- means for transmitting said multidirectional source signals encoded in at least one auxiliary channel with predetermined amplitude and phase relations differently indicative of source directions relative to the amplitude and phase relations of the multidirectional signals encoded in said two monaural and stereo compatible channels,
- means for decoding the signals of all of said transmission channels to form multidirectional presentation signals wherein said decoding of all of said transmission channels is carried out by decoding said two monaural and stereo compatible channels to provide a first set of more than two loudspeaker presentation signals for presentation at more than two listening space bearing angles and having source signals corresponding to every source direction appearing in plurality of such presentation signals but in different relative amplitude and decoding said auxiliary channel or channels to provide a second set of a plurality of presentation signals for presentation at listening space bearing angles corresponding to the listening space bearing angle presentation directions of said first set of presentation signals, and
- means for adding to each of said first set of presentation signals the signal of said second set of presentation signals for the corresponding listening space bearing angle to provide a plurality of output signals for the presentation directions corresponding to the presentation directions of said first set of presentation signals but with a sharpened directionality pattern with respect to that of said first set of presentation signals.
- 2. Reproduction apparatus in accordance with claim 1, wherein there are apparatus for transmitting four encoded audio input signals representing an orthogonal directional array and wherein apparatus is provided for including at least three of said four audio input signals in each of said two monaural and stereo compatible channels.
- 3. Reproduction apparatus in accordance with claim 2, wherein said apparatus for transmitting four encoded audio input signals comprises apparatus for transmitting encoded signals corresponding to source directions of front, back, right and left, with the signals being of the type wherein said predetermined amplitude and phase relations of said source signals in said two monaural and stereo compatible channels, designated T.sub.L and T.sub.R for left and right transmission channel, respectively, are
- T.sub.L =S.sub.L +0.707 S.sub.F.angle.+ 45.degree.+0.707 S.sub.B .angle.-45.degree.
- T.sub.R =S.sub.R +0.707 S.sub.F .angle.-45.degree.+0.707 S.sub.B .angle.+45.degree.
- where S.sub.F is the source signal from the front direction, S.sub.R is the source signal from the right direction, S.sub.B is the source signal from the back direction and S.sub.L is the source signal from the left direction.
- 4. Reproduction apparatus in acordance with claim 2, wherein said apparatus for transmitting four encoded audio input signals comprises apparatus for transmitting encoded signals corresponding to source directions of left front, left back, right front and right back, with the signals being of the type wherein said predetermined amplitude and phase relations of said source signals in said two monaural and stereo compatible channels, designated T.sub.L and T.sub.R for left and right transmission channel, respectively, are
- T.sub.L =0.924 S.sub.LF .angle.+221/2.degree.+0.383 S.sub.RF .angle.+671/2.degree.+0.383 S.sub.RB .angle.-671/2.degree.+0.924 S.sub.LB .angle.-221/2.degree.
- T.sub.R =0.383 S.sub.LF .angle.-671/2.degree.+0.924 S.sub.RF .angle.-221/2.degree.+0.924 S.sub.RB .angle.+221/2.degree.+0.383 S.sub.LB .angle.+671/2.degree.
- where S.sub.LF is the source signal fom the left front direction, S.sub.LB is the source signal from the left back direction, S.sub.RF is the source signal from the right front direction and S.sub.RB is the source signal from the right back direction.
Parent Case Info
This is a continuation, of application Ser. No. 578,078, filed May 16, 1975, now U.S. Pat. No. 3,970,788.
This application is a continuation-in-part of my copending application filed Oct. 6, 1971, Ser. No. 187,065.
US Referenced Citations (7)
Non-Patent Literature Citations (3)
Entry |
"Multichannel Stereo Matrix Systems", by Eargle in Journal of Audio Engr. Soc., Jul.-Aug. 1971, vol. 19, No. 7. |
"On the Processing of Two-and Three-Channel . . . ", by Eargle in Journal of Audio Engr. Soc., Apr. 1971, vol. 19, No. 4, pp. 262-266. |
"Further Improvements in Discrete Four-Channel . . . " by Owaki et al, in Journal of Audio Engr. Soc., Jun. 1972, vol. 20, No. 5, pp. 361-369. |
Continuations (1)
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578078 |
May 1975 |
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Continuation in Parts (1)
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187065 |
Oct 1971 |
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