Linear filterLinear filters process time-varying input signals to produce output signals, subject to the constraint of linearity. In most cases these linear filters are also time invariant (or shift invariant) in which case they can be analyzed exactly using LTI ("linear time-invariant") system theory revealing their transfer functions in the frequency domain and their impulse responses in the time domain. Real-time implementations of such linear signal processing filters in the time domain are inevitably causal, an additional constraint on their transfer functions.
Noise gateA noise gate or gate is an electronic device or software that is used to control the volume of an audio signal. Comparable to a compressor, which attenuates signals above a threshold, such as loud attacks from the start of musical notes, noise gates attenuate signals that register below the threshold. However, noise gates attenuate signals by a fixed amount, known as the range. In its simplest form, a noise gate allows a main signal to pass through only when it is above a set threshold: the gate is "open".
Pedal keyboardA pedalboard (also called a pedal keyboard, pedal clavier, or, with electronic instruments, a bass pedalboard) is a keyboard played with the feet that is usually used to produce the low-pitched bass line of a piece of music. A pedalboard has long, narrow lever-style keys laid out in the same semitone scalar pattern as a manual keyboard, with longer keys for C, D, E, F, G, A and B, and shorter, raised keys for C, D, F, G and A. Training in pedal technique is part of standard organ pedagogy in church music and art music.
George HarrisonGeorge Harrison (25 February 1943 – 29 November 2001) was an English musician, singer and songwriter who achieved international fame as the lead guitarist of the Beatles. Sometimes called "the quiet Beatle", Harrison embraced Indian culture and helped broaden the scope of popular music through his incorporation of Indian instrumentation and Hindu-aligned spirituality in the Beatles' work. Although the majority of the band's songs were written by John Lennon and Paul McCartney, most Beatles albums from 1965 onwards contained at least two Harrison compositions.
Electric bluesElectric blues is blues music distinguished by the use of electric amplification for musical instruments. The guitar was the first instrument to be popularly amplified and used by early pioneers T-Bone Walker in the late 1930s and John Lee Hooker and Muddy Waters in the 1940s. Their styles developed into West Coast blues, Detroit blues, and post-World War II Chicago blues, which differed from earlier, predominantly acoustic-style blues. By the early 1950s, Little Walter was a featured soloist on blues harmonica using a small hand-held microphone fed into a guitar amplifier.
Acoustic musicAcoustic music is music that solely or primarily uses instruments that produce sound through acoustic means, as opposed to electric or electronic means. While all music was once acoustic, the retronym "acoustic music" appeared after the advent of electric instruments, such as the electric guitar, electric violin, electric organ and synthesizer. Acoustic string instrumentations had long been a subset of popular music, particularly in folk.
Audio filterAn audio filter is a frequency dependent circuit, working in the audio frequency range, 0 Hz to 20 kHz. Audio filters can amplify (boost), pass or attenuate (cut) some frequency ranges. Many types of filters exist for different audio applications including hi-fi stereo systems, musical synthesizers, effects units, sound reinforcement systems, instrument amplifiers and virtual reality systems. Low-pass Low-pass filters pass through frequencies below their cutoff frequencies, and progressively attenuates frequencies above the cutoff frequency.
VibratoVibrato (Italian, from past participle of "vibrare", to vibrate) is a musical effect consisting of a regular, pulsating change of pitch. It is used to add expression to vocal and instrumental music. Vibrato is typically characterised in terms of two factors: the amount of pitch variation ("extent of vibrato") and the speed with which the pitch is varied ("rate of vibrato"). In singing it can occur spontaneously through variations in the larynx. The vibrato of a string instrument and wind instrument is an imitation of that vocal function.
FlangingFlanging 'flaendZIN is an audio effect produced by mixing two identical signals together, one signal delayed by a small and (usually) gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and notches are produced in the resulting frequency spectrum, related to each other in a linear harmonic series. Varying the time delay causes these to sweep up and down the frequency spectrum. A flanger is an effects unit that creates this effect.
Ring modulationIn electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal. One signal, called the carrier, is typically a sine wave or another simple waveform; the other signal is typically more complicated and is called the input or the modulator signal. A ring modulator is an electronic device for ring modulation. A ring modulator may be used in music synthesizers and as an effects unit.
