Multi-Channel Noise Reduction System with Direct Instrument Tracking

Abstract

A multi-channel noise reduction system provides improved noise reduction with direct instrument tracking of all channels. In a two channel noise reduction system, both channels detect and track the input level and dynamic range of the guitar directly with one channel of dynamic noise reduction between the guitar and the input of a guitar amplifier to eliminate the noise of the instrument and another channel of noise reduction connected in the effects loop of the guitar amplifier. Multiple channels of noise reduction can be implemented with separated threshold controls and with low level expansion and dynamic filtering being combined so as to detect and track the input level and dynamic range of the guitar directly. A buffer amplifier can be used to feed the direct guitar signal to the detectors of the noise reduction system and the input of a stereo guitar system.

What is claimed is: 
     
         1 . A method for reducing noise in a musical instrument sound system comprising the steps of:
 level detecting an instrument output signal to derive a dc control signal;   feeding the identical said instrument output signal to an instrument amplifier having an effects loop circuit; and   varying an output of the effects loop circuit in response to the dc control signal.   
     
     
         2 . A method according to  claim 1  further comprising the step of permitting user variation of a threshold for level detecting the instrument output signal. 
     
     
         3 . A musical instrument sound system noise reduction circuit comprising:
 means for detecting a level of an instrument output signal to derive a dc control signal;   means for amplifying the identical said instrument output signal, said amplifying means having an effects loop circuit; and   means for varying an output of the effects loop circuit in response to said dc control signal.   
     
     
         4 . A circuit according to  claim 3  further comprising means for permitting a user to vary a threshold of said level detecting means.