Reverberators for use in wide band assisted reverberation systems
A multi-channel reverberation system has a substantially constant multi-channel power gain at audio frequencies and comprises multiple signal inputs, one for each input channel, a number of comb filter networks connected to each signal input, each comb filter network including a feed forward stage, a cross-coupling network cross-coupling the comb filters to increase the reverberation echo density, and multiple signal outputs, one for each output channel. Preferably the feed forward stage of each comb filter provides a substantially constant multi-channel power gain at audio frequencies and the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.
1. A multi-channel reverberation system comprising:
multiple signal inputs, one for each input channel;
a number of feed back comb filter networks connected one to each signal input, each comb filter network including a feed forward stage to provide a substantially constant multi-channel power gain at audio frequencies;
a cross-coupled network cross-coupling the comb filters to increase the reverberation echo density;
and multiple signal outputs, one for each output channel.
2. A multi-channel reverberation system according to claim 1 , wherein the feed forward stage of the comb filters provides a transfer function matrix which is unitary at each frequency in the audio range.
3. A multi-channel reverberation system according to claim 1 , wherein the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.
4. An assisted reverberation or room acoustic enhancement system, comprising:
multiple microphones positioned to pick up reverberant sound in a room,
multiple loudspeakers to broadcast sound into the room, and
a multichannel reverberator, comprising:
multiple signal inputs, one for each input channel and which receive similar bandwidth signals from the microphones;
a number of feed back comb filter networks connected one to each signal input, each comb filter network including a feed forward stage to provide a substantially constant multi - channel power gain at audio frequencies;
a cross - coupling network cross - coupling the comb filters to increase the reverberation echo density;
and multiple signal outputs, one for each output channel.
5. An assisted reverberation or room acoustic enhancement system according to claim 4 , wherein the feed forward stage of the comb filters provides a transfer function matrix which is unitary at each frequency in the audio range.
6. An assisted reverberation or room acoustic enhancement system according to claim 4 , wherein the cross- coupling matrix is an orthogonal cross - coupling matrix cross - coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi - channel allpass comb filter with a unitary transfer function matrix at all frequencies.
7. A multi- channel unitary reverberator comprising:
multiple signal inputs, one for each input channel,
a number of feedback comb filter networks connected one to each signal input, each comb filter network including a feed forward stage to provide a substantially constant multi - channel power gain at audio frequencies, wherein there is one multiplier in each channel residing in both the feed forward and feedback networks,
a cross- coupling network cross coupling the comb filters to increase the reverberation echo density, and
multi signal outputs, one for each output channel.