Reproducing multichannel sound
AssigneeAnalog and Digital Systems, Inc.
InventorRichard E. DeFreitas
Life of this patent
Estimating the term…
Abstract
Apparatus for extracting recorded natural ambience from two audio channels while eliminating the cave-like quality of the sound of a soloist or announcer. The two channels are combined such that signals common to the two channels in a midrange of audio frequencies are cancelled, and the combined signal is time delayed.
Claims9
Apparatus for reproducing sound from a plurality of audio input channels, comprising:
- means for combining a first and second of said channels carrying a first signal and a second signal respectively such that signals common to the channels in a middle audio frequency range are attenuated, said means comprising
- means for phase shifting said first signal and
- means for summing said phase-shifted first signal with said second signal to produce an ambiance signal, and
- means for delaying said ambiance signal and providing said signal as an output.
A method for reproducing sound from a plurality of audio input channels, comprising the steps of:
- combining a first and second of said channels carrying first signal and a second signal respectively such that signals common to the channels in a middle audio frequency range are cancelled, by
- phase shifting said first signal and
- summing said phase-shifted first signal and said second signal to produce an ambiance signal, and
- delaying said ambiance signal.
Apparatus for reproducing sound from a plurality of audio input channels, comprising:
- means for combining a first and second of said channels carrying a first signal and a second signal respectively such that signals common to the channels in a middle audio frequency range are attenuated, said means comprising
- means for phase shifting said first signal and
- means for summing said phase-shifted first signal with said second signal to produce an ambiance signal, the audio frequency components of said first and second signals only being attenuated at or after summing by said means for summing, and
- means for delaying said ambiance signal and providing said signal as an output.
Apparatus for reproducing sound from a plurality of audio input channels, comprising:
- means for combining a first and second of said channels carrying a first signal and a second signal respectively such that signals common to the channels in a middle audio frequency range are attenuated, said means comprising
- means for phase-shifting said first signal wherein said means for phase-shifting only produces a relative phase shift between said first and second signals at frequencies at or below 3000 Hz so as to prevent attenuation of said common signals at frequencies above 3000 Hz and an increase in noise level in an ambiance signal,
- means for summing said phase-shifted first signal with said second signal to produce said ambiance signal, and
- means for delaying said ambiance signal and providing said signal as an output.
Dependencies are inferred from the claim text.