Patent ID: 6498852
Filing Date: 2002-12-24
Classification: H04S

Abstract:
A signal derivation processor for automatically deriving an audio LFE signal in multichannel soundtracks, said processor comprising:a plurality of main audio input channels; a plurality of audio output channels, one each corresponding to each of said main audio input channels; a low frequency effect output channel; a detector for one of each of said main audio input channels, said detector having programmable low frequency thresholds, said detector for analyzing the low frequency content of the incoming main channel signal and having at least one detector output signal; a variable shelving network for one of each of said main audio input channels for variable low frequency attenuation of the input signal when said programmable low frequency threshold of the signal is exceeded, said variable shelving network having an output signal; at least one variable gain amplifier for amplifying the input signal when said programmable low frequency threshold is exceeded, said variable gain amplifier under the control of said at least one detector output signal, said variable gain amplifier having an output signal; and a plurality of summing networks in series, said plurality being one less in number to the number of main channels, said summing networks summing the output signals of said variable gain amplifiers and having a signal to an LFE summing network, said LFE summing network feeding said low frequency effect output signal.