US20170103744A1 - Multi-Channel Noise Reduction System with Direct Instrument Tracking - Google Patents
Multi-Channel Noise Reduction System with Direct Instrument Tracking Download PDFInfo
- Publication number
- US20170103744A1 US20170103744A1 US15/383,001 US201615383001A US2017103744A1 US 20170103744 A1 US20170103744 A1 US 20170103744A1 US 201615383001 A US201615383001 A US 201615383001A US 2017103744 A1 US2017103744 A1 US 2017103744A1
- Authority
- US
- United States
- Prior art keywords
- guitar
- noise reduction
- amplifier
- channel
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000009467 reduction Effects 0.000 title claims abstract description 92
- 230000000694 effects Effects 0.000 claims abstract description 42
- 230000004044 response Effects 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 8
- 238000001914 filtration Methods 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 230000006872 improvement Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 210000003254 palate Anatomy 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H3/00—Instruments in which the tones are generated by electromechanical means
- G10H3/12—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument
- G10H3/14—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument using mechanically actuated vibrators with pick-up means
- G10H3/18—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument using mechanically actuated vibrators with pick-up means using a string, e.g. electric guitar
- G10H3/186—Means for processing the signal picked up from the strings
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/181—Low frequency amplifiers, e.g. audio preamplifiers
- H03F3/183—Low frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H2210/00—Aspects or methods of musical processing having intrinsic musical character, i.e. involving musical theory or musical parameters or relying on musical knowledge, as applied in electrophonic musical tools or instruments
- G10H2210/155—Musical effects
- G10H2210/311—Distortion, i.e. desired non-linear audio processing to change the tone color, e.g. by adding harmonics or deliberately distorting the amplitude of an audio waveform
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H2210/00—Aspects or methods of musical processing having intrinsic musical character, i.e. involving musical theory or musical parameters or relying on musical knowledge, as applied in electrophonic musical tools or instruments
- G10H2210/155—Musical effects
- G10H2210/315—Dynamic effects for musical purposes, i.e. musical sound effects controlled by the amplitude of the time domain audio envelope, e.g. loudness-dependent tone color or musically desired dynamic range compression or expansion
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H2250/00—Aspects of algorithms or signal processing methods without intrinsic musical character, yet specifically adapted for or used in electrophonic musical processing
- G10H2250/295—Noise generation, its use, control or rejection for music processing
- G10H2250/305—Noise or artifact control in electrophonic musical instruments
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/102—A non-specified detector of a signal envelope being used in an amplifying circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/372—Noise reduction and elimination in amplifier
Definitions
- the present invention relates generally to a method and system for providing improved tracking for musical instrument noise reduction systems and more particularly concerns such tracking in high gain guitar noise reduction systems.
- Noise reduction has continued to evolve and improve for many years providing the musician ongoing improvements in sound quality and reduced noise in live performances.
- Numerous patents have been issued for improvements in the area of noise reduction technology, including many of my inventions covered under U.S. Pat. Nos. 4,647,876, 4,696,044, 4,881,047, 4,893,099, 5,124,657, 5,263,091, 5,404,498 and 5,493,617.
- One benefit of my recently issued U.S. Pat. No. 6,944,305 is tracking the envelope of the input signal to provide a variable release response based on tracking the decay of the input signal.
- noise gate or noise reduction system The most common place to inset a noise gate or noise reduction system is in the effects loop of the instrument amplifier, which allows the noise reduction system to improve the dynamic range of the post distort signal. While this will reduce the background noise of the system, it also requires switching the noise reduction out of the signal path when the musician changes from a high gain distortion setting to a clean un-distorted sound. If the noise reduction system is not switched out, the threshold of the noise reduction system will be set so high that low-level signals will be undesirably truncated or attenuated.
- the improvements of the '305 patent finally allow the guitarist to eliminate the common problem of squealing feedback between short staccato notes caused by using extremely high gain in the guitar preamplifier if the noise reduction system is used between the guitar and the input of the amplifier.
- Noise reduction systems based on the '305 patent if connected between the instrument and the preamplifier, will allow extremely quick response reducing the gain of the instrument before feedback occurs by tracking the wide dynamic range of the guitar.
- the noise reduction system is inserted between the instrument and the input of the preamplifier, there is no effect of reducing the noise at the output of the high gain preamplifier.
- an object of this invention to provide a noise reduction system which does not track the small dynamic range at the output of a high gain guitar preamplifier. It is also an object of the invention to provide an improved multi-channel noise reduction system in which the level detection circuit for all channels tracks the instrument directly and allows one noise reduction channel to be placed between the instrument and the input of the guitar preamplifier and a second noise reduction channel to be inserted in the effects loop of the typical guitar amplifier. Another object of the current invention is to allow the guitar amplifier to be switched from a high gain setting to a low gain or clean setting without any need to change the threshold setting of the noise reduction system.
- a system and method for improving multi-channel noise reduction allowing all channels to detect and track the instrument directly.
- the musical instrument output signal is level detected to derive a dc control signal and also to an instrument amplifier which has an effects loop circuit.
- the output of the effects loop circuit is varied in response to the do control signal.
- the user may vary the threshold for level detection of the instrument output signal.
- the musical instrument output signal is fed via a first audio path to an instrument amplifier having an effects loop circuit connected to a second audio path and the outputs of the first and second audio paths are both varied in response to the dc control signal.
- the musical instrument output signal is fed via a first audio path to an instrument amplifier having an effects loop circuit connected to a second audio path and the outputs of the first and second audio paths.
- the musical instrument output signal is twice level detected to derive first and second dc control signals.
- the outputs of the first and second audio paths are varied in response to the first and second dc control signals, respectively, so that separate threshold controls can be applied in each audio path.
- the instrument output signal is fed to an instrument amplifier having a right effects loop circuit connected to a first audio path and a left effects loop circuit connected to a second audio path.
- the outputs of the first and second audio paths are varied in response to the dc control signal with a single level detection threshold control.
- the instrument output is level detected directly and the derived control signal applied to the effects loop circuit.
- FIG. 1A is a block diagram of a prior art system incorporating a noise reduction system used in the effects loop of a typical guitar amplifier;
- FIG. 1B is a block diagram of a prior art system incorporating a noise reduction system used between the guitar and the input of a typical guitar amplifier;
- FIG. 1C is a block diagram of a prior art system incorporating a stereo noise reduction system with one channel used between the guitar and the input of a typical guitar amplifier and a second channel inserted in the effects loop of the typical guitar amplifier;
- FIG. 2 is a block diagram of a first embodiment of the invention in which a single level detection circuit controls multiple channels of noise reduction with one channel of the noise reduction system between the guitar and the input of the guitar amplifier and a second channel of the noise reduction system inserted in the effects loop of the typical guitar amplifier;
- FIG. 3 is a block diagram of a second embodiment of the invention in which dual level detection circuits control multiple channels of noise reduction incorporating both low level expansion and dynamic filtering, with one channel of the noise reduction system used between the guitar and the input of the guitar amplifier and a second channel of the noise reduction system inserted in the effects loop of the typical guitar amplifier; and
- FIG. 4 is a block diagram of another embodiment of the invention for use in a true stereo guitar system in which the guitar plugs directly into the noise reduction system and a buffered output drives both the input of the stereo guitar system and an internal level detector for controlling multiple channels of noise reduction which are used after the guitar signal is split for stereo.
- FIG. 1A a block diagram of a prior art system is shown.
- the typical guitar amplifier used today is either a guitar head, which incorporates the circuitry shown as the guitar amplifier 20 , or a combo amplifier, which will also include the speaker in the cabinet together with all the components of the guitar amplifier 20 .
- the output of the guitar 10 is connected to the input 21 of the guitar amplifier 20 .
- the guitar amplifier 20 includes a preamp 23 , an effects loop circuit 25 and a power amplifier 27 serially connected as shown.
- the noise reduction system 40 is connected into the effects loop circuit 25 of the guitar amplifier 20 with the send output 29 of the guitar amplifier 20 connected to the input 41 of the noise reduction system 40 .
- the noise reduction input signal 41 is buffered by a buffer amplifier 43 and drives both the level detector 45 and the input of the audio path 47 which incorporates a VCA configured as a low level downward expander.
- the circuitry used for the noise reduction system 40 is well known to those skilled in the art and is disclosed in many of my previous patents listed in the background of the current invention.
- the output 49 of the level detector 45 is adjusted by a threshold control 51 .
- the detector output signal is applied to a voltage-controlled amplifier in the audio path 47 .
- the output 53 of the audio path 47 is fed to the return input 31 of the guitar amplifier 20 . While this system is effective at removing noise from the guitar 10 and gain noise generated by the high gain preamplifier 23 , it suffers from several problems in operation.
- the preamplifier 23 when set for high gain use, will provide compression of the signal to the guitar amplifier 20 and as a result will greatly reduce the dynamic range of the guitar signal appearing at the output of the preamplifier 23 . This requires the noise reduction system 40 to operate with the greatly reduced dynamic range that appears at the output of the preamplifier 23 .
- the threshold of the noise reduction system 40 becomes critical for correct operation of the noise reduction system 40 and any change in the gain or tone of the preamp 23 will require an appropriate change in the threshold 51 of the noise reduction system 40 .
- the noise reduction system 40 needs to be re-adjusted or switched out of the signal. This configuration is not extremely effective at eliminating the typical squealing feedback that is associated with the extremely high gain guitar amplifiers or worse, provides little impact if the guitarist uses an external overdrive pedal or circuit between the guitar 10 and the input 21 of the guitar amplifier 20 .
- the noise reduction system 40 is inserted in the signal path between the guitar 10 and the guitar amplifier 20 .
- the output of the guitar 10 is connected to the input 41 of the noise reduction system 40 and the output 53 is connected to the input 21 of the guitar amplifier 20 .
- the noise reduction system 40 detects the larger dynamic range of the guitar signal before any compression of the signal that would take place in the preamp 23 and allows the musician to change settings on the guitar amplifier 20 without requiring any changes in the noise reduction threshold 51 .
- Noise reduction systems which incorporate the advantages of the improved tracking response of the invention described in my '305 patent will also eliminate the common high gain squealing feedback associated with playing staccato notes.
- the noise reduction circuit 40 is before the output of the high gain preamplifier 23 , it will not be effective at reducing the noise of the preamp circuit 23 .
- a stereo noise reduction system 60 is used in conjunction with a typical guitar amplifier 20 .
- the channel 1 audio path 65 A is inserted between the guitar 10 and the input 21 of the guitar amplifier 20 and the channel 2 audio path 65 B is inserted in the effects loop circuit 25 of the guitar amplifier 20 .
- the guitar 10 is connected to the input 61 A of the noise reduction system 60 and the send output 29 of the effects loop circuit 25 .
- Two separate threshold settings 71 A and 71 B are required and the channel 2 noise reduction circuit will require a change in the setting of the threshold 71 B if the guitar preamplifier 23 settings are changed from high gain to low gain or if the tone of the preamplifier 23 is changed by the user.
- the detector output signals 49 A and 49 B control the audio outputs 73 A and 73 B.
- the output 73 A of the channel 1 audio path 67 A is connected to the input 21 of the guitar amplifier 20 .
- the output of the channel 2 audio path 67 B is connected to the return input 31 of the effects loop circuit 25 .
- Most musicians will switch the effects loop circuit 23 in when they are using a high gain setting and out when using a lower gain setting.
- FIG. 2 a first embodiment of the invention is shown.
- the guitar 10 is connected to the input 81 A of the noise reduction system 80 .
- the input signal is buffered by a buffer amplifier 83 A and the output signal of the buffer amplifier 83 A drives both the input of the channel 1 audio path 87 A and its audio level detector 85 .
- Audio level detectors described in detail in my above listed patents and known by those of ordinary skill in the art, are discussed only at the block level in this description. Various types of level detectors can be used, including peak, averaging and RMS detectors.
- the output 87 A of the level detector 85 is varied by the threshold control 91 , allowing the user to define the threshold level at which noise reduction begins.
- the output 87 A of the level detector 85 feeds the control port of both the audio paths 87 A and 87 B.
- Audio paths 87 A and 87 B each consist of a VCA (voltage controlled amplifier) configured as a low-level downward expander. Voltage controlled amplifiers, known by those of ordinary skill in the art and described in detail in my previous patents, are discussed only at the block level for this description. One of the most common voltage controlled amplifiers in use is part number 2181LC by THAT Corporation.
- the output 93 A of the channel one audio path 87 A is connected to the input 21 of the guitar amplifier 20 .
- the output of the preamp 23 in the guitar amplifier 20 feeds the effects loop circuit 25 , which allows the user to connect an external signal processing device such as a noise reduction system.
- the output 29 of the effects loop 25 is connected to the input 81 B of the noise reduction system 80 , buffered by a buffer amplifier 83 B and fed to the input of the channel 2 audio path 87 B.
- the output 93 B of the channel 2 audio path 87 B feeds the return input 31 of the effects loop circuit 25 in the guitar amplifier 20 .
- the output of the effects loop circuit 25 feeds the input of the power amplifier 27 .
- the output of the power amplifier 27 will drive an external speaker cabinet preferred by the guitarist in order to provide audible sound.
- the output level of the guitar 10 is detected by the audio level detector 85 , which converts the audio input signal into a DC signal 89 to control the voltage controlled amplifiers in the audio paths 89 A and 89 B.
- the threshold adjustment 91 of the level detector 85 allows the guitarist to set the threshold of the noise reduction system 80 so as to eliminate all background noise from the guitar 10 and any preamplifier high gain noise in the preamp 23 . Since the audio level detector 85 detects and tracks the signal direct from the guitar 10 and generates the control voltage 89 used to control the downward expanders in both audio paths 87 A and 87 B, changes in the gain and or tone of the preamp 23 will not require any user adjustment of the setting of the threshold 91 .
- he level detector 85 will detect the large dynamic range available from the guitar 10 , making the operation of the channel 2 audio path 87 B of the noise reduction circuit 80 connected in the effects loop circuit 25 far more responsive signal from the guitar 10 .
- the embodiment may also include the teachings of my —305 patent, which will make the release response characteristic of the noise reduction system 80 responsive to the decay envelope of the guitar 10 and will also add considerable transparency to the noise reduction system 80 .
- a multi-channel noise reduction system 100 incorporates the effect of both low level downward expansion and dynamic low pass filtering with dual channel level detectors 105 A and 105 B and threshold controls 111 A and 111 B.
- a detailed description of the operation of dynamic filtering is disclosed in my U.S. Pat. Nos. 4,647,876, 4,696,044, 5,124,657 and 5,596,646.
- Each of the channel level detectors. 105 A and 105 B includes two level detectors, the first for controlling the response of the dynamic filters 106 A and 106 B, respectively, and the second for controlling the response of the voltage controlled amplifiers 108 A and 108 B, respectively.
- single threshold controls 111 A and 111 B can be implemented for each pair of level detectors.
- the output of the guitar 10 is fed to the input 101 A of the noise reduction system 100 and buffered by the buffer amplifier 103 A.
- the output of the buffer amplifier 103 A feeds the input of the channel 1 audio path 107 A, which includes both the dynamic filter 106 A and the voltage controlled amplifier 108 A.
- the output of the buffer amplifier 103 A also feeds the inputs of both groups of level detectors in the channel level detectors 105 A and 105 B.
- the threshold controls 111 A and 111 B allow the user to adjust for the threshold set points of the level detectors 105 A and 105 B, respectively.
- the output 113 A of the channel 1 audio path is connected to the input 21 of the guitar amplifier 20 and fed to the input of the preamp 23 .
- the send output 29 of the effects loop circuit 25 feeds the input 101 B of the noise reduction system 100 .
- the signal at the input 101 B is buffered by the buffer amplifier 103 B and fed to the channel 2 audio path 107 B.
- the output 113 B of the channel 2 audio path 107 B is connected to the return input 31 of the effects loop circuit 25 .
- the output level of the guitar 10 is buffered by the buffer amplifier 101 A and then detected by audio level detectors contained in the channel detectors 105 A and 105 B to provide DC control voltages 109 A and 109 B which control the dynamic filters 106 A and 106 B, respectively, and DC control voltages 110 A and 110 B for controlling the voltage controlled amplifiers 108 A and 108 B, respectively.
- the threshold adjustment 111 A allows the guitarist to adjust the threshold set point for the level detector 105 A. The guitarist can, therefore, set the noise reduction threshold of the channel 1 audio path 107 A so as to eliminate all background noise, hum and buzz from the guitar 10 before the signal is fed to the input 21 of the guitar amplifier 20 .
- the channel 1 audio path 106 A of the noise reduction system 100 will also allow the guitarist to set this threshold 111 A so as to eliminate high gain squealing that may occur when playing short staccato notes with a high gain setting for the preamp 23 .
- the threshold adjustment 111 B allows the guitarist to adjust the threshold set point for the level detector 105 B. The guitarist can, therefore, set the noise reduction threshold of the channel 2 audio path 107 B so as to eliminate any high gain noise, hiss and hum present in the output of the preamp 23 .
- the embodiment of FIG. 3 allows the user to more precisely set the threshold for both the operation of the channel 1 audio path 107 A for reducing noise picked up directly by the guitar 10 and the threshold for the operation of the channel 2 audio path 107 B, which controls the noise produced by the guitar preamp circuit 23 . Since both the channel 1 and the channel 2 level detectors 105 A and 105 E track the input of the guitar 10 directly, both noise reduction channels respond to the full dynamic range of the guitar 10 , allowing the user to make adjustments to the guitar amplifier 20 without any need to change the threshold settings of the noise reduction system 100 .
- the embodiment of FIG. 3 may also include the teachings of my '305 patent, which will make the release response characteristic of the noise reduction system 100 responsive to the decay envelope of the guitar 10 and will also add considerable transparency to the noise reduction system 100 .
- FIG. 4 another embodiment of the invention allows operation with a true stereo guitar system 220 .
- the embodiment of FIG. 4 is illustrative and one of ordinary skill in the art will understand that there are endless possible configurations of equipment that can be used in a custom guitar system. For years guitarists have built high performance stereo guitar systems using separate components. Typically these consist of 19 inch rack-mount components such as guitar preamplifiers, compressors, equalizers, effects processors and many other separate components. In some systems the musician will also use multiple guitar preamplifiers to generate a stereo signal. As shown in FIG.
- the output of the guitar 10 is connected to the input 241 of the noise reduction system 240 and buffered by a buffer amplifier 243 A which allows the noise reduction system 240 to capture the high impedance input signal 244 of the guitar 10 to feed the input of the audio level detector 255 .
- the noise reduction system 200 may also include multiple level detectors and multiple threshold controls as shown in FIG. 3 , multiple threshold controls, and may further implement both processes of downward expansion and dynamic filtering as shown in FIG. 3 .
- the output 245 of the buffer amplifier 243 is connected to the input of the guitar preamp 223 of the stereo guitar system 220 .
- the output of the preamp 223 feeds two separate effects paths including right effects circuit 225 A and left effects circuit 225 B.
- the effects circuit 225 A and 225 B may include any number of guitar and or studio processors.
- the output of the right effects circuit 225 A is fed to the input 246 A of the noise reduction system 220 , buffered by the buffer amplifier 247 A and fed to the channel 1 audio path 249 A.
- the output 251 A of the channel 1 audio path 249 A is connected to the input of the right amplifier 226 A of the stereo guitar system 220 .
- the output of the left effects circuit 2258 is fed to the input 246 B of the noise reduction system 220 , buffered by the buffer amplifier 247 B and fed to the channel 2 audio path 240 B.
- the output 251 B of the channel 2 audio path 249 B is connected to the input of the left amplifier 226 B of the stereo guitar system 220 .
- the outputs of the right and left amplifiers 226 A and 226 B are connected to speakers 227 A and 227 B, respectively, to provide audible sound for the guitar system.
- the output of the guitar 10 is buffered and fed to both the input of the level detector 255 and the input of the stereo guitar system 220 .
- This allows the stereo guitar system 220 to process the guitar signal and generate stereo output signals to feed the two audio path inputs 246 A and 2468 of the noise reduction system 220 .
- the user adjustable threshold 261 will be set based on the type of guitar used and preferences of the guitarist using the system. Once the threshold is set the user can make changes to the guitar preamp 23 as well as the right and the left effects circuits 225 A and 225 B without any required changes in the threshold adjustment 261 .
- a further advantage of this embodiment is that the level detector 255 will detect the full dynamic range available from the guitar 10 , making the operation of both the channel 1 and channel 2 noise reduction circuits far more responsive to the guitar signal than would be possible with prior art systems.
- the embodiment shown in FIG. 4 may also include the teachings of my '305 patent, which will make the release response characteristic of the noise reduction system 220 responsive to the decay envelope of the guitar 10 and will also add considerable transparency to the noise reduction system 220 .
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.
Description
- This application is a continuation of U.S. application Ser. No. 13/154,183, filed Jun. 6, 2011, which is a continuation of U.S. application Ser. No. 11/302,296, filed Dec. 13, 2005, now U.S. Pat. No. 7,957,546.
- The present invention relates generally to a method and system for providing improved tracking for musical instrument noise reduction systems and more particularly concerns such tracking in high gain guitar noise reduction systems. Noise reduction has continued to evolve and improve for many years providing the musician ongoing improvements in sound quality and reduced noise in live performances. Numerous patents have been issued for improvements in the area of noise reduction technology, including many of my inventions covered under U.S. Pat. Nos. 4,647,876, 4,696,044, 4,881,047, 4,893,099, 5,124,657, 5,263,091, 5,404,498 and 5,493,617. One benefit of my recently issued U.S. Pat. No. 6,944,305 is tracking the envelope of the input signal to provide a variable release response based on tracking the decay of the input signal.
- While these improvements have offered a major advance in the overall performance of noise reduction for musicians, and in particular the guitarist, there has been a lack of improvement available in reducing the noise, particularly in extremely high gain applications. When the noise reduction system has the ability to track the level and wide dynamic range of the instrument directly, it's easy to have a controlled, and accurate response from the noise reduction system. However, typical modern guitarists use extremely high gain and distortion as a major part of their sound palate. When driving any guitar preamplifier into extreme distortion, the output signal becomes highly compressed and the dynamic range is reduced to as little as 5 to 10 decibels. This reduction in dynamic range makes it extremely difficult, if not impossible, for a noise reduction system to determine the difference between the background noise and the desirable instrument signal. The most common place to inset a noise gate or noise reduction system is in the effects loop of the instrument amplifier, which allows the noise reduction system to improve the dynamic range of the post distort signal. While this will reduce the background noise of the system, it also requires switching the noise reduction out of the signal path when the musician changes from a high gain distortion setting to a clean un-distorted sound. If the noise reduction system is not switched out, the threshold of the noise reduction system will be set so high that low-level signals will be undesirably truncated or attenuated. The improvements of the '305 patent finally allow the guitarist to eliminate the common problem of squealing feedback between short staccato notes caused by using extremely high gain in the guitar preamplifier if the noise reduction system is used between the guitar and the input of the amplifier. Noise reduction systems based on the '305 patent, if connected between the instrument and the preamplifier, will allow extremely quick response reducing the gain of the instrument before feedback occurs by tracking the wide dynamic range of the guitar. However, when the noise reduction system is inserted between the instrument and the input of the preamplifier, there is no effect of reducing the noise at the output of the high gain preamplifier. Using two channels of noise reduction will improve this problem but, as described above, requires the noise reduction system at the output of the preamplifier to operate with as little as 5 to 10 decibels of dynamic range and also requires the system to be switched out to avoid the side effect of chopping off any low level signal in a low gain setting.
- It is, therefore, an object of this invention to provide a noise reduction system which does not track the small dynamic range at the output of a high gain guitar preamplifier. It is also an object of the invention to provide an improved multi-channel noise reduction system in which the level detection circuit for all channels tracks the instrument directly and allows one noise reduction channel to be placed between the instrument and the input of the guitar preamplifier and a second noise reduction channel to be inserted in the effects loop of the typical guitar amplifier. Another object of the current invention is to allow the guitar amplifier to be switched from a high gain setting to a low gain or clean setting without any need to change the threshold setting of the noise reduction system. Yet another object of the invention is to provide a system where both low-level downward expansion and dynamic low pass filtering as a composite noise reduction audio processing block for multiple channels can track the instrument directly. Yet another object of the current invention is to provide the ability to have multiple audio channels of noise reduction for use in a stereo or multi-channel guitar system where all of the audio channels detection circuit track the instrument directly and the audio signal can be inserted after the use of a high gain preamplifier.
- In accordance with the present invention, a system and method is disclosed for improving multi-channel noise reduction allowing all channels to detect and track the instrument directly.
- The musical instrument output signal is level detected to derive a dc control signal and also to an instrument amplifier which has an effects loop circuit. The output of the effects loop circuit is varied in response to the do control signal. The user may vary the threshold for level detection of the instrument output signal.
- In one embodiment, the musical instrument output signal is fed via a first audio path to an instrument amplifier having an effects loop circuit connected to a second audio path and the outputs of the first and second audio paths are both varied in response to the dc control signal.
- In another embodiment, the musical instrument output signal is fed via a first audio path to an instrument amplifier having an effects loop circuit connected to a second audio path and the outputs of the first and second audio paths. The musical instrument output signal is twice level detected to derive first and second dc control signals. The outputs of the first and second audio paths are varied in response to the first and second dc control signals, respectively, so that separate threshold controls can be applied in each audio path.
- In yet another embodiment the instrument output signal is fed to an instrument amplifier having a right effects loop circuit connected to a first audio path and a left effects loop circuit connected to a second audio path. The outputs of the first and second audio paths are varied in response to the dc control signal with a single level detection threshold control.
- In every embodiment, the instrument output is level detected directly and the derived control signal applied to the effects loop circuit.
- Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
-
FIG. 1A is a block diagram of a prior art system incorporating a noise reduction system used in the effects loop of a typical guitar amplifier; -
FIG. 1B is a block diagram of a prior art system incorporating a noise reduction system used between the guitar and the input of a typical guitar amplifier; -
FIG. 1C is a block diagram of a prior art system incorporating a stereo noise reduction system with one channel used between the guitar and the input of a typical guitar amplifier and a second channel inserted in the effects loop of the typical guitar amplifier; -
FIG. 2 is a block diagram of a first embodiment of the invention in which a single level detection circuit controls multiple channels of noise reduction with one channel of the noise reduction system between the guitar and the input of the guitar amplifier and a second channel of the noise reduction system inserted in the effects loop of the typical guitar amplifier; -
FIG. 3 is a block diagram of a second embodiment of the invention in which dual level detection circuits control multiple channels of noise reduction incorporating both low level expansion and dynamic filtering, with one channel of the noise reduction system used between the guitar and the input of the guitar amplifier and a second channel of the noise reduction system inserted in the effects loop of the typical guitar amplifier; and -
FIG. 4 is a block diagram of another embodiment of the invention for use in a true stereo guitar system in which the guitar plugs directly into the noise reduction system and a buffered output drives both the input of the stereo guitar system and an internal level detector for controlling multiple channels of noise reduction which are used after the guitar signal is split for stereo. - While the invention will be described in connection with several preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the, invention as defined by the appended claims.
- Turning first to
FIG. 1A , a block diagram of a prior art system is shown. The typical guitar amplifier used today is either a guitar head, which incorporates the circuitry shown as theguitar amplifier 20, or a combo amplifier, which will also include the speaker in the cabinet together with all the components of theguitar amplifier 20. In either case, the output of theguitar 10 is connected to theinput 21 of theguitar amplifier 20. Theguitar amplifier 20 includes apreamp 23, aneffects loop circuit 25 and apower amplifier 27 serially connected as shown. Thenoise reduction system 40 is connected into theeffects loop circuit 25 of theguitar amplifier 20 with thesend output 29 of theguitar amplifier 20 connected to theinput 41 of thenoise reduction system 40. The noisereduction input signal 41 is buffered by abuffer amplifier 43 and drives both thelevel detector 45 and the input of theaudio path 47 which incorporates a VCA configured as a low level downward expander. The circuitry used for thenoise reduction system 40 is well known to those skilled in the art and is disclosed in many of my previous patents listed in the background of the current invention. - Continuing to look at
FIG. 1A , theoutput 49 of thelevel detector 45 is adjusted by athreshold control 51. The detector output signal is applied to a voltage-controlled amplifier in theaudio path 47. Theoutput 53 of theaudio path 47 is fed to thereturn input 31 of theguitar amplifier 20. While this system is effective at removing noise from theguitar 10 and gain noise generated by thehigh gain preamplifier 23, it suffers from several problems in operation. Thepreamplifier 23, when set for high gain use, will provide compression of the signal to theguitar amplifier 20 and as a result will greatly reduce the dynamic range of the guitar signal appearing at the output of thepreamplifier 23. This requires thenoise reduction system 40 to operate with the greatly reduced dynamic range that appears at the output of thepreamplifier 23. Setting the threshold of thenoise reduction system 40 becomes critical for correct operation of thenoise reduction system 40 and any change in the gain or tone of thepreamp 23 will require an appropriate change in thethreshold 51 of thenoise reduction system 40. When the musician changes or switches the settings of theguitar amplifier 20, thenoise reduction system 40 needs to be re-adjusted or switched out of the signal. This configuration is not extremely effective at eliminating the typical squealing feedback that is associated with the extremely high gain guitar amplifiers or worse, provides little impact if the guitarist uses an external overdrive pedal or circuit between theguitar 10 and theinput 21 of theguitar amplifier 20. - Considering
FIG. 1B , in an alternative prior art method thenoise reduction system 40 is inserted in the signal path between theguitar 10 and theguitar amplifier 20. In this configuration, the output of theguitar 10 is connected to theinput 41 of thenoise reduction system 40 and theoutput 53 is connected to theinput 21 of theguitar amplifier 20. Thenoise reduction system 40 detects the larger dynamic range of the guitar signal before any compression of the signal that would take place in thepreamp 23 and allows the musician to change settings on theguitar amplifier 20 without requiring any changes in thenoise reduction threshold 51. Noise reduction systems which incorporate the advantages of the improved tracking response of the invention described in my '305 patent will also eliminate the common high gain squealing feedback associated with playing staccato notes. However, since thenoise reduction circuit 40 is before the output of thehigh gain preamplifier 23, it will not be effective at reducing the noise of thepreamp circuit 23. - Turning to
FIG. 1C , in yet another prior art method, a stereo noise reduction system 60 is used in conjunction with atypical guitar amplifier 20. Thechannel 1audio path 65A is inserted between theguitar 10 and theinput 21 of theguitar amplifier 20 and thechannel 2audio path 65B is inserted in theeffects loop circuit 25 of theguitar amplifier 20. Theguitar 10 is connected to theinput 61 A of the noise reduction system 60 and thesend output 29 of theeffects loop circuit 25. Two separate threshold settings 71A and 71B are required and thechannel 2 noise reduction circuit will require a change in the setting of the threshold 71B if theguitar preamplifier 23 settings are changed from high gain to low gain or if the tone of thepreamplifier 23 is changed by the user. This is done by use of twoaudio level detectors buffer amplifiers audio outputs output 73A of thechannel 1 audio path 67A is connected to theinput 21 of theguitar amplifier 20. The output of thechannel 2audio path 67B is connected to thereturn input 31 of theeffects loop circuit 25. Most musicians will switch theeffects loop circuit 23 in when they are using a high gain setting and out when using a lower gain setting. - Looking at
FIG. 2 , a first embodiment of the invention is shown. Theguitar 10 is connected to theinput 81A of thenoise reduction system 80. The input signal is buffered by abuffer amplifier 83A and the output signal of thebuffer amplifier 83A drives both the input of thechannel 1audio path 87A and itsaudio level detector 85. Audio level detectors, described in detail in my above listed patents and known by those of ordinary skill in the art, are discussed only at the block level in this description. Various types of level detectors can be used, including peak, averaging and RMS detectors. Theoutput 87A of thelevel detector 85 is varied by the threshold control 91, allowing the user to define the threshold level at which noise reduction begins. Theoutput 87A of thelevel detector 85 feeds the control port of both theaudio paths 87A and 87B.Audio paths 87A and 87B each consist of a VCA (voltage controlled amplifier) configured as a low-level downward expander. Voltage controlled amplifiers, known by those of ordinary skill in the art and described in detail in my previous patents, are discussed only at the block level for this description. One of the most common voltage controlled amplifiers in use is part number 2181LC by THAT Corporation. Theoutput 93A of the channel oneaudio path 87A is connected to theinput 21 of theguitar amplifier 20. The output of thepreamp 23 in theguitar amplifier 20 feeds theeffects loop circuit 25, which allows the user to connect an external signal processing device such as a noise reduction system. Theoutput 29 of theeffects loop 25 is connected to theinput 81B of thenoise reduction system 80, buffered by abuffer amplifier 83B and fed to the input of thechannel 2 audio path 87B. Theoutput 93B of thechannel 2 audio path 87B feeds thereturn input 31 of theeffects loop circuit 25 in theguitar amplifier 20. The output of theeffects loop circuit 25 feeds the input of thepower amplifier 27. In use, the output of thepower amplifier 27 will drive an external speaker cabinet preferred by the guitarist in order to provide audible sound. - Continuing to look at
FIG. 2 , in operation, the output level of theguitar 10 is detected by theaudio level detector 85, which converts the audio input signal into aDC signal 89 to control the voltage controlled amplifiers in the audio paths 89A and 89B. The threshold adjustment 91 of thelevel detector 85 allows the guitarist to set the threshold of thenoise reduction system 80 so as to eliminate all background noise from theguitar 10 and any preamplifier high gain noise in thepreamp 23. Since theaudio level detector 85 detects and tracks the signal direct from theguitar 10 and generates thecontrol voltage 89 used to control the downward expanders in bothaudio paths 87A and 87B, changes in the gain and or tone of thepreamp 23 will not require any user adjustment of the setting of the threshold 91. Furthermore, he leveldetector 85 will detect the large dynamic range available from theguitar 10, making the operation of thechannel 2 audio path 87B of thenoise reduction circuit 80 connected in theeffects loop circuit 25 far more responsive signal from theguitar 10. The embodiment may also include the teachings of my —305 patent, which will make the release response characteristic of thenoise reduction system 80 responsive to the decay envelope of theguitar 10 and will also add considerable transparency to thenoise reduction system 80. - Turning to
FIG. 3 , in a second embodiment of the invention a multi-channelnoise reduction system 100 incorporates the effect of both low level downward expansion and dynamic low pass filtering with dualchannel level detectors 105A and 105B and threshold controls 111A and 111B. A detailed description of the operation of dynamic filtering is disclosed in my U.S. Pat. Nos. 4,647,876, 4,696,044, 5,124,657 and 5,596,646. Each of the channel level detectors. 105A and 105B includes two level detectors, the first for controlling the response of the dynamic filters 106A and 106B, respectively, and the second for controlling the response of the voltage controlledamplifiers 108A and 108B, respectively. It will be apparent to those of ordinary skill in the art that single threshold controls 111A and 111B can be implemented for each pair of level detectors. In operation, the output of theguitar 10 is fed to theinput 101A of thenoise reduction system 100 and buffered by the buffer amplifier 103A. The output of the buffer amplifier 103A feeds the input of thechannel 1audio path 107A, which includes both the dynamic filter 106A and the voltage controlledamplifier 108A. The output of the buffer amplifier 103A also feeds the inputs of both groups of level detectors in thechannel level detectors 105A and 105B. The threshold controls 111A and 111B allow the user to adjust for the threshold set points of thelevel detectors 105A and 105B, respectively. Theoutput 113A of thechannel 1 audio path is connected to theinput 21 of theguitar amplifier 20 and fed to the input of thepreamp 23. Thesend output 29 of theeffects loop circuit 25 feeds the input 101B of thenoise reduction system 100. The signal at the input 101B is buffered by the buffer amplifier 103B and fed to thechannel 2audio path 107B. Theoutput 113B of thechannel 2audio path 107B is connected to thereturn input 31 of theeffects loop circuit 25. - Continuing to look at
FIG. 3 , in operation the output level of theguitar 10 is buffered by thebuffer amplifier 101 A and then detected by audio level detectors contained in thechannel detectors 105A and 105B to provideDC control voltages 109A and 109B which control the dynamic filters 106A and 106B, respectively, andDC control voltages amplifiers 108A and 108B, respectively. The threshold adjustment 111A allows the guitarist to adjust the threshold set point for thelevel detector 105A. The guitarist can, therefore, set the noise reduction threshold of thechannel 1audio path 107A so as to eliminate all background noise, hum and buzz from theguitar 10 before the signal is fed to theinput 21 of theguitar amplifier 20. Thechannel 1 audio path 106A of thenoise reduction system 100 will also allow the guitarist to set this threshold 111A so as to eliminate high gain squealing that may occur when playing short staccato notes with a high gain setting for thepreamp 23. Similarly, the threshold adjustment 111B allows the guitarist to adjust the threshold set point for the level detector 105B. The guitarist can, therefore, set the noise reduction threshold of thechannel 2audio path 107B so as to eliminate any high gain noise, hiss and hum present in the output of thepreamp 23. - The embodiment of
FIG. 3 allows the user to more precisely set the threshold for both the operation of thechannel 1audio path 107A for reducing noise picked up directly by theguitar 10 and the threshold for the operation of thechannel 2audio path 107B, which controls the noise produced by theguitar preamp circuit 23. Since both thechannel 1 and thechannel 2level detectors 105A and 105E track the input of theguitar 10 directly, both noise reduction channels respond to the full dynamic range of theguitar 10, allowing the user to make adjustments to theguitar amplifier 20 without any need to change the threshold settings of thenoise reduction system 100. The embodiment ofFIG. 3 may also include the teachings of my '305 patent, which will make the release response characteristic of thenoise reduction system 100 responsive to the decay envelope of theguitar 10 and will also add considerable transparency to thenoise reduction system 100. - Looking now at
FIG. 4 , another embodiment of the invention allows operation with a truestereo guitar system 220. The embodiment ofFIG. 4 is illustrative and one of ordinary skill in the art will understand that there are endless possible configurations of equipment that can be used in a custom guitar system. For years guitarists have built high performance stereo guitar systems using separate components. Typically these consist of 19 inch rack-mount components such as guitar preamplifiers, compressors, equalizers, effects processors and many other separate components. In some systems the musician will also use multiple guitar preamplifiers to generate a stereo signal. As shown inFIG. 4 , the output of theguitar 10 is connected to theinput 241 of the noise reduction system 240 and buffered by a buffer amplifier 243A which allows the noise reduction system 240 to capture the highimpedance input signal 244 of theguitar 10 to feed the input of theaudio level detector 255. It will be apparent to those of ordinary skill in the art that the noise reduction system 200 may also include multiple level detectors and multiple threshold controls as shown inFIG. 3 , multiple threshold controls, and may further implement both processes of downward expansion and dynamic filtering as shown inFIG. 3 . As seen inFIG. 4 , theoutput 245 of thebuffer amplifier 243 is connected to the input of theguitar preamp 223 of thestereo guitar system 220. The output of thepreamp 223 feeds two separate effects paths including right effects circuit 225A and lefteffects circuit 225B. As described above, in practice theeffects circuit 225A and 225B may include any number of guitar and or studio processors. The output of the right effects circuit 225A is fed to theinput 246A of thenoise reduction system 220, buffered by thebuffer amplifier 247A and fed to thechannel 1audio path 249A. Theoutput 251 A of thechannel 1audio path 249A is connected to the input of the right amplifier 226A of thestereo guitar system 220. The output of the left effects circuit 2258 is fed to theinput 246B of thenoise reduction system 220, buffered by thebuffer amplifier 247B and fed to thechannel 2 audio path 240B. Theoutput 251B of thechannel 2 audio path 249B is connected to the input of theleft amplifier 226B of thestereo guitar system 220. The outputs of the right and leftamplifiers 226A and 226B are connected tospeakers - Continuing to look at
FIG. 4 , in operation the output of theguitar 10 is buffered and fed to both the input of thelevel detector 255 and the input of thestereo guitar system 220. This allows thestereo guitar system 220 to process the guitar signal and generate stereo output signals to feed the twoaudio path inputs 246A and 2468 of thenoise reduction system 220. The user adjustable threshold 261 will be set based on the type of guitar used and preferences of the guitarist using the system. Once the threshold is set the user can make changes to theguitar preamp 23 as well as the right and theleft effects circuits 225A and 225B without any required changes in the threshold adjustment 261. A further advantage of this embodiment is that thelevel detector 255 will detect the full dynamic range available from theguitar 10, making the operation of both thechannel 1 andchannel 2 noise reduction circuits far more responsive to the guitar signal than would be possible with prior art systems. The embodiment shown inFIG. 4 may also include the teachings of my '305 patent, which will make the release response characteristic of thenoise reduction system 220 responsive to the decay envelope of theguitar 10 and will also add considerable transparency to thenoise reduction system 220. - Thus, it is apparent that there has been provided, in accordance with the invention, a disguised automobile antenna that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it will be evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the forgoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.
Claims (4)
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.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/383,001 US20170103744A1 (en) | 2005-12-13 | 2016-12-19 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/302,296 US7957546B2 (en) | 2005-12-13 | 2005-12-13 | Multi-channel noise reduction system with direct instrument tracking |
US13/154,183 US20110308377A1 (en) | 2005-12-13 | 2011-06-06 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
US15/383,001 US20170103744A1 (en) | 2005-12-13 | 2016-12-19 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/154,183 Continuation US20110308377A1 (en) | 2005-12-13 | 2011-06-06 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
Publications (1)
Publication Number | Publication Date |
---|---|
US20170103744A1 true US20170103744A1 (en) | 2017-04-13 |
Family
ID=38139406
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/302,296 Active 2030-04-02 US7957546B2 (en) | 2005-12-13 | 2005-12-13 | Multi-channel noise reduction system with direct instrument tracking |
US13/154,183 Abandoned US20110308377A1 (en) | 2005-12-13 | 2011-06-06 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
US15/383,001 Abandoned US20170103744A1 (en) | 2005-12-13 | 2016-12-19 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/302,296 Active 2030-04-02 US7957546B2 (en) | 2005-12-13 | 2005-12-13 | Multi-channel noise reduction system with direct instrument tracking |
US13/154,183 Abandoned US20110308377A1 (en) | 2005-12-13 | 2011-06-06 | Multi-Channel Noise Reduction System with Direct Instrument Tracking |
Country Status (2)
Country | Link |
---|---|
US (3) | US7957546B2 (en) |
WO (1) | WO2007070590A2 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9040806B1 (en) * | 2005-12-13 | 2015-05-26 | James K. Waller, Jr. | Multi-channel noise reduction system with direct instrument tracking |
US7957546B2 (en) * | 2005-12-13 | 2011-06-07 | Waller Jr James K | Multi-channel noise reduction system with direct instrument tracking |
US20070189572A1 (en) * | 2006-01-30 | 2007-08-16 | Eugene Stanley Juall | Loudspeaker system for acoustic instruments and method therefor |
US8916761B2 (en) * | 2009-01-10 | 2014-12-23 | Kevin Arthur Robertson | Audio coupling device to couple an electric musical instrument to a handheld computing device |
US8816182B2 (en) * | 2009-01-10 | 2014-08-26 | Kevin Arthur Robertson | Digital audio connections for portable handheld computing devices |
US8772620B2 (en) * | 2009-01-10 | 2014-07-08 | Kevin Robertson | Processing audio signals with portable handheld computing devices |
US9173025B2 (en) | 2012-02-08 | 2015-10-27 | Dolby Laboratories Licensing Corporation | Combined suppression of noise, echo, and out-of-location signals |
US8712076B2 (en) | 2012-02-08 | 2014-04-29 | Dolby Laboratories Licensing Corporation | Post-processing including median filtering of noise suppression gains |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020154786A1 (en) * | 2001-04-23 | 2002-10-24 | Waller James K. | Audio dynamics processing control system |
US6522752B1 (en) * | 1992-09-17 | 2003-02-18 | Randall C. Smith | Parallel channel multi mode music amplifier |
US7957546B2 (en) * | 2005-12-13 | 2011-06-07 | Waller Jr James K | Multi-channel noise reduction system with direct instrument tracking |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3992584A (en) * | 1975-05-09 | 1976-11-16 | Dugan Daniel W | Automatic microphone mixer |
US4672671A (en) * | 1984-12-03 | 1987-06-09 | Carter Duncan Corporation | Audio frequency signal preamplifier for providing controlled output signals |
US4893099A (en) * | 1985-02-25 | 1990-01-09 | Waller Jr James K | Extended response dynamic noise reduction system |
US4647876A (en) * | 1985-02-25 | 1987-03-03 | Waller Jr James | Extended response dynamic noise reduction system |
US4696044A (en) * | 1986-09-29 | 1987-09-22 | Waller Jr James K | Dynamic noise reduction with logarithmic control |
US4881047A (en) * | 1988-06-20 | 1989-11-14 | Waller Jr James K | Automatic gain expansion system |
US5124657A (en) * | 1989-10-06 | 1992-06-23 | Waller Jr James K | Composite signal processor and single-ended noise reduction system |
US5404498A (en) * | 1990-12-04 | 1995-04-04 | The Furukawa Electric Co., Ltd. | Voltage setting apparatus in a multiplex transmission system |
US5493617A (en) * | 1991-10-09 | 1996-02-20 | Waller, Jr.; James K. | Frequency bandwidth dependent exponential release for dynamic filter |
US5263091A (en) * | 1992-03-10 | 1993-11-16 | Waller Jr James K | Intelligent automatic threshold circuit |
US5789689A (en) * | 1997-01-17 | 1998-08-04 | Doidic; Michel | Tube modeling programmable digital guitar amplification system |
-
2005
- 2005-12-13 US US11/302,296 patent/US7957546B2/en active Active
-
2006
- 2006-12-13 WO PCT/US2006/047573 patent/WO2007070590A2/en active Application Filing
-
2011
- 2011-06-06 US US13/154,183 patent/US20110308377A1/en not_active Abandoned
-
2016
- 2016-12-19 US US15/383,001 patent/US20170103744A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6522752B1 (en) * | 1992-09-17 | 2003-02-18 | Randall C. Smith | Parallel channel multi mode music amplifier |
US20020154786A1 (en) * | 2001-04-23 | 2002-10-24 | Waller James K. | Audio dynamics processing control system |
US6944305B2 (en) * | 2001-04-23 | 2005-09-13 | James K Waller | Audio dynamics processing control system |
US7957546B2 (en) * | 2005-12-13 | 2011-06-07 | Waller Jr James K | Multi-channel noise reduction system with direct instrument tracking |
Also Published As
Publication number | Publication date |
---|---|
WO2007070590A2 (en) | 2007-06-21 |
US7957546B2 (en) | 2011-06-07 |
US20110308377A1 (en) | 2011-12-22 |
US20070133825A1 (en) | 2007-06-14 |
WO2007070590A3 (en) | 2008-04-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20170103744A1 (en) | Multi-Channel Noise Reduction System with Direct Instrument Tracking | |
US4748669A (en) | Stereo enhancement system | |
US7162046B2 (en) | Microphone-tailored equalizing system | |
US5133015A (en) | Method and apparatus for processing an audio signal | |
US5506910A (en) | Automatic equalizer | |
US4701957A (en) | Dual mode music instrument preamplifier | |
KR100671360B1 (en) | Audio correction system and audio sound enhancement method | |
US6246773B1 (en) | Audio signal processors | |
US20140044282A1 (en) | Active Instrument Subwoofer System for Low Frequency Enhancement | |
US9438994B2 (en) | Instrument amplification systems incorporating reflection cancelling boundary microphones and multiband compression | |
US6627808B1 (en) | Acoustic modeling apparatus and method | |
US9877134B2 (en) | Techniques for optimizing the fidelity of a remote recording | |
JP4347153B2 (en) | Acoustic characteristic adjustment device | |
US9040806B1 (en) | Multi-channel noise reduction system with direct instrument tracking | |
US4202238A (en) | Compressor-expander for a musical instrument | |
US9306510B1 (en) | Frequency dependent dual solid-state and vacuum tube power amplifier-section instrument amplifier | |
US20230386438A1 (en) | Audio signal management system | |
KR100269711B1 (en) | Noise improvement method of digital audio system | |
JPH0936683A (en) | Automatic sound volume control circuit | |
US8121318B1 (en) | Two channel audio surround sound circuit with automatic level control | |
KR100324747B1 (en) | Circuit for removing noise of voice | |
JPH0575366A (en) | Signal processing circuit in audio equipment | |
KR940000106Y1 (en) | Simultaneous treatment circuit for very low frequency and surround sound | |
KR960016672B1 (en) | Apparatus for regulating separately audio volume and treble/bass of r.l channel in audio system | |
EP3148215A1 (en) | A method of modifying audio signal frequency and system for modifying audio signal frequency |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |