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ADSR Abbreviation for Attack, Decay, Sustain, and Release. These are the four parameters found on a basic synthesizer envelope generator, and they correlate to the physical characteristics of naturally generated sounds. An envelope generator is sometimes called a transient generator. The Attack, Decay, and Release parameters are rate or time controls. Sustain is a level. When a key is pressed, the envelope generator will begin to rise to its full level at the rate set by the attack parameter, upon reaching peak level it will begin to fall at the rate set by the decay parameter to the level set by the sustain control. The envelope will remain at the sustain level as long as the key is held down. When a key is released, it will return to zero at the rate set by the release parameter.

ADDITIVE SYNTHESIS The process of constructing a complex sound using a series of fundamental frequencies (pure tones or sine waves). Each of the fundamental frequencies usually has its own amplitude envelope, which allows independent control of each partial (harmonic). Pipe organs or Hammond organs are both instruments, which are based on additive synthesis.

AFTER TOUCH See Pressure Sensitivity

ALAISING Aliasing is the term used to describe the unwanted frequencies, which are produced when a sound is sampled at a rate, which is less than twice the frequency of the highest frequency component in the sound. These unwanted frequencies are typically high frequency noises similar to a metallic ringing sound.

AMPLIFIER A device, which increases the level of an electrical signal.

AMPLITUDE Amplitude is a term used to describe the amount of a signal. It can relate to volume in an audio signal or the amount of voltage in an electrical signal.

AMPLITUDE MODULATION A change in the level of a signal. For example, if a Low Frequency Oscillator (LFO) was modulating a Voltage Controlled Amplifier (VCA), the result would be a periodic increase and decrease in the audio level of the signal. In musical terms this would be referred to as Tremolo. The abbreviation of Amplitude Modulation is AM.

ANALOG Analogue equipment basically utilise analogue signals & circuitry...coming from the word ANALOGOUS...or directly proportionate to... An analogue signal electrically, is a directly proportionate electrical representation of the sound waves it is emulating.... so, if you have a sound wave of a given Frequency & amplitude, the electrical signal will have the same frequency signal and amplitude....

ANALOG SYNTHESIZER A synthesizer, which uses voltage, controlled analogue modules to synthesize sound. Dr. Robert Moog invented the concept of a variety of analogue modules all of which can interconnect via a standardized voltage control system. The three main voltage controlled modules/components in an analogue synthesizer are: Voltage Controlled Oscillator (VCO...Produces the raw tone wave...), Voltage Controlled Filter (VCF...affects the tone or sharpness of the sound...), and Voltage Controlled Amplifier (VCA.... controls the volume characteristics).

APERIODIC WAVEFORM a waveform that does not have a repeating pattern.

ARPEGGIO/ARPEGGIATOR If you form a chord shape on an instrument, and play the chord ascending or descending one note at a time, this is an Arpeggio.... Much loved by metal Axe heroes...An Arpeggiator, is a device or computer program that sequentially moves a pattern of notes over a range of the keyboard automatically. The speed of the Arpeggiation is variable and the pattern can usually be varied depending on the order or relationship of the notes pressed.

ATTACK the first parameter of an envelope generator, which determines the rate, or time it will take for the sound to reach the highest level before starting to decay.

ATTENUATOR Attenuate means to reduce in force, value or amount.... An Attenuator is a device that reduces the value of something, usually the amplitude of a signal.

AUDIBLE RANGE the range of frequencies that the human ear can hear. A healthy young human can usually hear from 20 cycles per second to around 20,000 cycles per second (20-20,000 Hz), less after the age of about 13 - 14,and even less with prolonged exposure to Heavy Metal music, Opera, or continuous use of loud headphones.

AUTO CORELLATION a process that determines optimum start and ending loop points to produce minimum discontinuity.