Each input channel adjusts a level of an audio signal by individual first parameters and outputs the level-adjusted audio signals to individual output routes that include bus channels. Each bus channel mixes the level-adjusted audio signals and processes the mixed audio signal by a second parameter to output to a main output. A preview channel adjusts a level of the audio signal of each of input channels by a third parameter, mixes the level-adjusted audio signals of the input channels and processes the mixed audio signal by a fourth parameter to output to a monitor output. In response to a preview instruction, the first parameter of the input channel is copied as the third parameter, and the second parameter of the bus channel is copied as the fourth parameter of the preview channel. In response to an adjustment instruction, the third or fourth parameter of the preview channel is changed.

A speaker driving device including a setting part setting at least one parameter defining an equivalent circuit of a first speaker unit as a first parameter; a first calculator configured to change a first frequency response based on the first parameter, the changed first frequency response being applied to an input signal; and a driving signal generator configured to generate a drive signal for driving a speaker unit based on a first calculation signal, the first calculation signal being obtained by applying the changed first frequency response to the input signal.

An exemplary modular musical instrument amplification system may comprise a chassis including a power supply, an input gain stage, a control processor and a plurality of modular slots. The modular slots are configured to receive any of a plurality of preamplifier modules for establishing an electrical communication therewith. The input gain stage has a modifiable response behavior and is in signal amplifying communication between at least one instrument input jack and the modular slots. The control processor is preferably in control communication between the modular slots and the input gain stage. Each preamplifier module has a respective input stage profile associated therewith. The control processor may be configured for sensing the input stage profile of a preamplifier module received in an active modular slot, and setting the response behavior based, at least in part, upon the respective input stage profile.

A frequency estimation apparatus and method for a single receiver. The frequency estimation apparatus for the single receiver includes: a coarse frequency estimation unit estimating a coarse frequency by calculating an average of frequency estimation values for each single pulse; a direct current domain transformation unit transforming a reception signal into a direct current domain based on the coarse frequency; a fine frequency estimation unit estimating a fine frequency by applying regression analysis to a pulse train in the direct current domain of the coarse frequency; and an extremely fine frequency estimation unit estimating an extremely fine frequency by compensating an error of the coarse frequency with the fine frequency.

An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.

Systems and methods for holistically modelling audio feedback and removing the entire feedback signal corresponding thereto. The systems can operate at a much larger loop-gain (and hence with a much higher loudspeaker volume), than those conventional systems which seek to remove singing frequencies with PEQs. The systems are an improvement over traditional audio feedback elimination systems which attempt to reduce the effect of the audio feedback by simply scaling down the audio volume of the signal frequencies that are prone to howling, and those feedback elimination systems which simply employ adaptive notch filtering to detect and notch the so-called singing or howling frequencies as they occur in real-time. Such devices may typically have several knobs and buttons needing tuning, for example: the number of adaptive parametric equalizers (PEQs) versus fixed PEQs; attack and decay timers; and/or PEQ bandwidth. The systems set forth herein obviate the need for tuning knobs or buttons, making set up easy.

A preamplifier for musical instruments includes: an operational amplifier 40 to amplify an inputted analog audio signal; a dual-unit variable resistor 30 to change an amplification factor of the operational amplifier 40 by manually operating an operation unit; an A/D converter 51 to convert the amplified analog audio signal to a digital audio signal; and a digital signal processor 60 to digital-signal process the digital audio signal, wherein the dual-unit variable resistor 30 includes a second variable resistor 32 to output a detection signal in accordance with an amount of operation of the operation unit, and the digital signal processor 60 is capable of implementing, based on a value of the detection signal, a first digital gain process to amplify the digital audio signal and/or a second digital gain process to attenuate the digital audio signal.

A preamplifier for musical instruments includes: an operational amplifier 40 to amplify an inputted analog audio signal; a dual-unit variable resistor 30 to change an amplification factor of the operational amplifier 40 by manually operating an operation unit; an A/D converter 51 to convert the amplified analog audio signal to a digital audio signal; and a digital signal processor 60 to digital-signal process the digital audio signal, wherein the dual-unit variable resistor 30 includes a second variable resistor 32 to output a detection signal in accordance with an amount of operation of the operation unit, and the digital signal processor 60 is capable of implementing, based on a value of the detection signal, a first digital gain process to amplify the digital audio signal and/or a second digital gain process to attenuate the digital audio signal.

An audio processing system includes a server complex in communication with a network. The server complex receives a digital audio file and one or more analog domain control settings from a client device across the network. A digital-to-analog converter converts the digital audio file to an analog signal. One or more analog signal processors apply at least one analog modification to the analog signal in accordance with the one or more analog domain control settings. An analog-to-digital converter converts the modified analog signal to a modified digital audio file. The server complex can then deliver the modified digital audio file to the client device across the network.

An audio processing system includes a server complex in communication with a network. The server complex receives a digital audio file and one or more analog domain control settings from a client device across the network. A digital-to-analog converter converts the digital audio file to an analog signal. One or more analog signal processors apply at least one analog modification to the analog signal in accordance with the one or more analog domain control settings. An analog-to-digital converter converts the modified analog signal to a modified digital audio file. The server complex can then deliver the modified digital audio file to the client device across the network.