1. A method for simplifying a model of an acoustic environment (1), wherein said model comprises a set of transfer functions, each transfer function corresponding to the sound propagation (4, 5) from a sound emitting position (2) to a sound receiving position (3) in said acoustic environment (1), the method comprising, for each transfer function, the step of:
calculating a simulated reverberation of a first stimulus emitted at said sound emitting position as received at said sound receiving position by applying said transfer function to said first stimulus;
characterised in that the method further comprises the steps of:
selecting a subset (31, 32, 35) of a set of local maxima (31, 32, 33, 34, 35) in an intensity envelope (30) of the simulated reverberation; and
calculating a simplified transfer function which, applied to said first stimulus, provides a simulated reverberation with an intensity envelope matching said selected subset (31,32, 35) of local maxima (31, 32, 33, 34, 35).
2. A method as claimed in claim 1 where the number of said selected subset (31, 32, 35) of local maxima (31, 32, 33, 34, 35) is not higher than a predetermined maximum.
3. A method as claimed in claim 1, wherein said selected subset (31, 32, 35) of local maxima (31, 32, 33, 34, 35) is selected from among those above a time-intensity attenuation function.
4. A method as claimed in claim 3, wherein said attenuation function is an exponential attenuation function.
5. A method as claimed in claim 1, wherein said simplified transfer function is applied by convolution with said first stimulus.
6. A method as claimed in claim 1, wherein said simplified transfer function is expressed as a combination of a signal delay and a signal attenuation for each selected local maximum (31, 32, 35), and is applied to said first stimulus in a time domain operation.
7. A method for converting an first audio stream comprising N input channels into a second audio stream comprising M output channels, the method comprising, for each input and output channel, the steps of:
selecting, in a model of an M-channel acoustic environment (1) simplified using a method according to claim 1, a simplified transfer function associated with said input channel and output channel; and
processing an input signal from said input channel by applying said selected simplified transfer function to generate at least part of an output signal for said output channel.
8. A method as claimed in claim 7, wherein M>N.
9. A method as claimed in claim 7, wherein the selected subsets (31, 32, 35) of local maxima (31, 32, 33, 34, 35) matched by the simplified transfer functions are different for at least two of the M output channels, and preferably for all M output channels.
10. A method as claimed in claim 4, wherein said output signal comprises an early part (31, 32, 33, 34, 35) and a late part (91).
11. A method as claimed in claim 10 wherein only the early part (91) is generated using said simplified transfer function.
12. A method as claimed in claim 11, wherein the late part (91) is generated by algorithmic reverberation of the input signal.
13. A converter (50) for converting a first audio signal comprising N input channels (54) into a second audio signal comprising M calculated channels (55), using a method according to claim 7, the converter (50) comprising:
N inputs (54) and M outputs (55); and
a processor (51) for applying said set of simplified transfer functions to an audio signal received on an input channel (54) so as to obtain reverberation components of a calculated output channel (55); and
characterized in that the converter (50) also comprises a data carrier (52) with at least coefficients associated with said set of simplified transfer functions, for use by said processor (51).
14. A converter as claimed in claim 13, wherein said data carrier (52) is a transient computer memory connected to said processor (50).
15. A signal comprising a simplified model of an acoustical reference room (1) obtained by the method of claim 1.
16. A data carrier (81) comprising a signal according to claim 15.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A coupling comprising:
a pair of clutch end members, each said end member including a set of concentric V-grooves disposed on a respective face thereof;
a clutch centre member disposed between the clutch end members, the centre member being axially movable between the end members and including a pair of opposing surfaces, one of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of one of the end members, another of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of another of the end members; and
an actuator coupled to one of the end members and being configured to couple the end members and the centre member together by urging the V-grooves of the end members into engagement with the V-grooves of the centre member.
2. The coupling according to claim 1, wherein the actuator is configured to couple the end members and the centre member together by urging the face of the one end member against the one surface of the centre member until engagement of the another surface of the centre member with the face of the another end member.
3. The coupling according to claim 2, wherein the centre member has a radially outer end and a radially inner end, the opposing surfaces are disposed at an acute angle relative to each other such that the centre member is thinner at the outer end than at the inner end, and each end member face is parallel to the associated opposing surface.
4. The coupling according to claim 1, wherein each said V-groove comprises a root disposed between adjacent peaks, and the roots of the one opposing surface of the centre member are radially offset from the roots of the another opposing surface.
5. The coupling according to claim 1, further comprising a centering mechanism coupled to the centre member and configured to urge the center member away from the end members upon deactivation of the actuator.
6. The coupling according to claim 5, wherein the centering mechanism comprises one of a ball bearing and a spring coupled to a rotational shaft, the centre member has a radially outer end and a radially inner end, and the radially inner end is configured for mounting to the rotational shaft and comprises a recess configured for capturing the centering mechanism therein.
7. The coupling according to claim 6, wherein the recess comprises a V-shaped pocket.
8. The coupling according to claim 1, wherein the centre member has a radially outer end and a radially inner end, each said V-groove provided on the centre member comprises a root disposed between adjacent peaks, and the centre member comprises at least one oil passage configured to facilitate a cascading oil flow to the V-grooves of the end members.
9. The coupling according to claim 1, wherein the centre member has a radially outer end and a radially inner end, each said V-groove provided on the centre member comprises a root disposed between adjacent peaks, and the centre member comprises at least one oil passage extending radially through a plurality of the roots towards the inner end.
10. The coupling according to claim 9, wherein the centre member comprises a plurality of the oil passages each extending through a respective number of the roots in accordance with an angular position of the oil passage.
11. The coupling according to claim 1, wherein one of the end members has a radially outer end and a radially inner end, each said V-groove provided on the one end member comprises a root disposed between adjacent peaks, and the one end member comprises at least one oil passage configured to provide a flow of oil to the associated V-grooves of the centre member.
12. The coupling according to claim 1, wherein one of the end members has a radially outer end and a radially inner end, each said V-groove provided on the one end member comprises a root disposed between adjacent peaks, and the one end member comprises at least one oil passage, each said oil passage comprising a through-hole extending axially from one of the roots towards an opposite face of the one end member, and a slot provided in the opposite face and extending radially from the through-hole towards the inner end.
13. The coupling according to claim 12, wherein the one end member comprises a plurality of the oil passages disposed at varying radial positions around the one end member.
14. The coupling according to claim 1, wherein the centre member comprises a pair of clutch plates, and a spring disposed between the clutch plates and urging the clutch plates axially apart, the clutch plates being configured for rotation in unison about a common axis of rotation, one of the clutch plates being axially movable with respect to another of the clutch plates, the one clutch plate comprising one of the opposing surfaces, the another clutch plate comprising the another of the opposing surfaces.
15. A transmission drive-line stage comprising:
a transmission housing; and
a torque input member, a torque reactive member, a torque output member, and the coupling according to any one of claims 1 to 14 and configured to transfer torque between the torque input member and the torque output member,
wherein the torque input member, the torque reactive member, the torque output member and the coupling are disposed within the transmission housing, and the torque output member is coupled to the torque input member and the torque reactive member.
16. A transmission drive-line stage comprising:
a torque input member; a torque reactive member; a torque output member; and a pair of torque couplings, the torque output member being coupled to the torque input member and the torque reactive member, the torque couplings being configured to transfer torque between the torque input member and the torque output member, each said torque coupling being disposed within a transmission case and being configured to provide a respective gear ratio between the torque input member and the torque output member, each said torque coupling comprising:
a pair of clutch end members, each said end member including a set of concentric V-grooves disposed on a respective face thereof;
a clutch centre member disposed between the respective clutch end members, the centre member being axially movable between the respective end members and including a pair of opposing surfaces, one of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of one of the respective end members, another of the opposing surfaces including a plurality of concentric V-grooves configured to mesh with the set of V-grooves of another of the respective end members; and
an actuator coupled to one of the respective end members and being configured to couple the end members and the centre member together by urging the V-grooves of the respective end members into engagement with the V-grooves of the centre member;
wherein one of the end members of one of the torque couplings is coupled to the transmission case, the centre member of the one torque coupling is coupled to the torque reactive member, one of the end members of another of the torque couplings is coupled to the torque reactive member, and the centre member of the another torque coupling is coupled to the torque input member.
17. The transmission drive-line stage according to claim 16, wherein the actuator of the one torque coupling is operable independently of the actuator of the another torque coupling.
18. The transmission drive-line stage according to claim 16, wherein the actuator of the another torque coupling is configured to uncouple the end members and the centre member thereof in synchronism with activation of the actuator of the one torque coupling, such that an increase in torque between the end members and the centre member in the one torque coupling is accompanied by a corresponding decrease in torque between the end members and the centre member in the another torque coupling.
19. The transmission drive-line stage according to claim 16, wherein the actuator of the one torque coupling comprises a piston, and the actuator of the another torque coupling comprises a biasing spring urging the end members and the centre member thereof together, the piston and the biasing spring being configured to limit drive-line torque discontinuity during transition between the gear ratios.
20. The transmission drive-line stage according to claim 19, wherein the centre member of the one torque coupling comprises a pair of clutch plates, and the biasing spring is disposed between the clutch plates and urges the clutch plates axially apart, the clutch plates being configured for rotation in unison about a common axis of rotation, one of the clutch plates being axially movable with respect to another of the clutch plates, the one clutch plate comprising one of the opposing surfaces of the one torque coupling, the another clutch plate comprising the another of the opposing surfaces of the one torque coupling and further comprising one of the end members of the another torque coupling.
21. The transmission drive-line stage according to claim 20, wherein the actuator of the another torque coupling is configured to couple the end and centre members thereof together by urging the face of the one end member of the another torque coupling against the one surface of the centre member thereof until engagement of the another surface of the centre member thereof with the face of the another end member of the another torque coupling.
22. The transmission drive-line stage according to claim 21, wherein the centre member of the another torque coupling has a radially outer end and a radially inner end, the opposing surfaces thereof are disposed at an acute angle relative to each other such that the centre member of the another torque coupling is thinner at the outer end than at the inner end, and each end member face thereof is parallel to the associated opposing surface.
23. The transmission drive-line stage according to claim 20, wherein each said V-groove of the centre member of the one torque coupling comprises a root disposed between adjacent peaks, and the roots of the one clutch plate are radially offset from the roots of the another clutch plate.
24. The transmission drive-line stage according to claim 16, wherein the another torque coupling comprises a centering mechanism coupled to the centre member thereof and configured to urge the center member thereof away from the respective end members.
25. The transmission drive-line stage according to claim 24, wherein the centering mechanism comprises one of a ball bearing and a spring coupled to the torque input member, the centre member thereof has a radially outer end and a radially inner end, and the radially inner end of the centre member of the another torque coupling comprises a recess configured for capturing the centering mechanism therein.
26. The transmission drive-line stage according to claim 24, wherein the centre member of the another torque coupling is selectively coupled to the torque input member via one of a cone coupling and a synchromesh gear set.
27. The transmission drive-line stage according to claim 26, wherein the torque input member comprises a torque input shaft and a sun gear provided on the torque input shaft, the torque reactive member comprises an annular gear, and the torque output member comprises one of a planetary gear set and a coplanar reverted gear loop coupled to the annular gear and the sun gear.
28. The transmission drive-line stage according to claim 20, wherein the torque, reactive member comprises at least one axially-extending finger, and the clutch plates are mounted on the at least one finger and rotate with the torque reactive member, the one clutch plate being axially movable along the at least one finger, the another clutch plate being fixed to the at least one finger.
29. The transmission drive-line stage according to claim 28, wherein the end plates of the another torque coupling rotate with the torque reactive member and are axially movable along the at least one finger.