Behringer UB-Xa User Manual - Page 31

31 UB-Xa User Manual Glossary ADSR - Envelope generator with four stages: Attack, Decay, Sustain and Release. Amplitude - The volume of a sound. Aftertouch - MIDI data sent when pressure is applied to the keyboard after keys have been played, but while they are still being held. Arpeggiator - a part of the synthesizer which causes the notes of a chord to be played individually as an arpeggio according to settings. Atrophy - To degrade or to get worse. The sound of Vintage synthesizers changes over time, a model fresh from production line would not sound the same after 30 years, Indeed our beta tester's original synthesizers all sound slightly different. This is because the physical electronic components inside will 'atrophy'. The atrophy menu is to be able to give the user options to be able to make small tweaks to the voice engine, so the sound becomes not perfect and to make it sound more like what they expect an OB-Xa to sound like. Attack Time - The first stage of the envelope. Specified as the time taken for the envelope to reach maximum level when keys are played. Attenuate - To reduce the level of a signal or modulation source. Bank - A collection of a number of patches. Cent - Unit of measurement for tuning. One semitone is divided into 100 cents. Cutoff Frequency - The point at which the filter starts to cut frequencies. Decay Time - The second stage of the envelope. Specified as the time taken for the sound level to drop from maximum to the sustain level while the played keys are being held. Digital Audio Workstation (DAW) - A computer based software package that allows the recording, editing and playing back of audio and/or MIDI data. Envelope Generator - Envelope generators can be used to contour the sound. Most commonly used to affect the amplitude (volume) of the sound they can also be used on filters and to affect pitch. Filter - Filters attenuate the frequencies above or below their cutoff point, thus affecting the timbre of the sound. Frequency Modulation (FM) - The use of one frequency to modulate another. Typically the use of a low frequency from a low frequency oscillator to add vibrato or tremolo to a sound, but could also be the use of one audio level frequency to modulate another, which would cause a change in timbre. Frequency - The number of cycles per second (Hz) that an oscillator runs at. Global - parameters that affect all patches. Hertz (Hz) - Unit of measurement for frequencies. 1 Hz is one cycle per second. Invert - change to the opposite, so a positive becomes negative for example. Keyboard Tracking - Use of the notes played on the keyboard to adjust another parameter, for example. KiloHertz (kHz) - Common abbreviation for one thousand Hz. Low Frequency Oscillator (LFO) - An oscillator that runs at a low speed and is used to modulate other parts of the synthesiser. MPE - MIDI Polyphonic Expression (also known as Multidimensional Polyphonic Expression). Please see the MPE chapter for a full explanation of MPE. Musical Instrument Digital Interface (MIDI) - a protocol that allows musical instruments, other peripherals and DAWs to pass data according to a defined standard. MIDI Clock - a timing signal that is sent as part of the MIDI data. MIDI Message - data transmitted from one MIDI device to another that constitutes an instruction. Mix - The balance between two or more signals. Modulation - The use of sources to control a parameter of a destination. Monophonic - Only allowing one note to be played at a time. Noise - A random sound comprising of all frequencies. Note Priority - Determines which note is played when the maximum number is exceeded. Typically lowest, highest or last. Octave - A measure of pitch. Oscillator (Osc or VCO) - The basic sound source of the synthesizer. Oscillator Sync - The process by which the cycle of one oscillator is synchronized to the cycle of another. Output - Can refer both to the signal sent out from one part of the synthesizer to another, or to the physical sockets used to connect to external equipment. Parameter - A setting whose value can be changed. Patch - A stored combination of parameters that make up a sound. Phase - The measurement in degrees of the time difference between two waveforms or a waveform and a fixed reference point. Pitch Bend - Changing the pitch of a note up or down while it is being played. Polyphonic - Capable of playing more than one note at a time, expressed as a number of voices. Portamento - The effect of 'gliding' the pitch between notes rather than changing instantly. Pulse Wave - A wave similar to a square wave, but whose symmetry can be changed. Pulse Width Modulation - The modulation of the symmetry of a pulse wave. Rate - The speed at which an action takes place. Release Time - The final stage of the envelope. Specified as the time taken for the envelope to reach zero once keys have been released. Resonance - The emphasis of frequencies centered on the cutoff frequency. Sample & Hold (S&H) - the sampling of a waveform, typically that of an LFO or noise source, to provide a series of voltages at a set rate. Sawtooth - A waveform resembling the teeth of a saw, with an instantaneous leading edge followed by a gradual decline to zero point. Self Oscillation - The point at which a filter starts to produce a sine wave output owing to excessive use of resonance. Semitone - A measure of pitch. Each octave contains 12 semitones. Sequencer - A part of the synthesizer which can be programmed with a series of notes and/or chords which are then repeated back at a selected tempo. Signal Flow - The path of a signal from one part of the synthesizer to another. Sine Wave - A smooth waveform that contains only the fundamental frequency with no harmonics. Square Wave - a symmetrical waveform which changes instantaneously from zero state to full. Sustain Level - The third stage of the envelope. This is the level that the envelope holds at after decay until keys are released. Synchronization (Sync) - Co-ordinating the timing of devices where one is the master and the other(s) are synchronized to it.