Neutron : What Are The Symbols, Terms and Abbreviations?

This glossary provides an explanation of useful symbols, terms and abbreviations.

For a full overview of the Neutron please take some time to familiarise yourself with the User Manual located here:

32'/16'/8': Used to describe the range of an oscillator, this term originates from pipe organs. for example, an 8' pipe is one octave higher than an 16' pipe.

DSR: Attack, Decay, Sustain and Release, an envelope with four stages.

Aftertouch: Aftertouch is MIDI data sent when pressure is applied to a keyboard after the key has been struck, and while it is being held down or sustained.

Attack Time: The first stage of an ADSR envelope, used to control the initial part of a sound. Specified as the duration of time for an envelope to reach the maximum level after it has been triggered on by a key press or gate signal. Attenuate: To reduce the level of a signal.

Band Pass Filter (BPF): A filter that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range.

Bipolar: a signal that includes positive and negative values.

Cent: Unit of measurement for pitch tuning. There are one hundred cents in a semitone.

Control Voltage (CV): A voltage signal used to control a parameter. Was common on synthesizers before MIDI and is now found mostly on modular synthesizers.

Cut-Off Frequency: The frequency which the filter is set to. Beyond this frequency the sound is cut depending on the type of filter used. See LPF, BPF and HPF.

dBu: A unit of measurement of sound used in professional audio.

DC Offset: A DC voltage which is added to an AC waveform.

Decay Time: The second stage of an ADSR envelope. Specified as the duration of time for an envelope to reach the sustain level after the maximum level has been reached during the attack stage.

Digital Audio Workstation (DAW): A computer-based recording system. More commonly used to describe the software package used to record, process and mix. Distortion: An effect which adds harmonic content to a signal.

Drive: Provide a gain boost to produce soft clipping.

Effect: One of a number of audio processes that can be applied to a signal to modify it, such as reverb, flanging, phasing, delay etc.

Envelope Generator (EG): An envelope signal which can be adjusted to a specific shape in order to control the way a sound behaves over time.

Feedback: A loop created between an audio input and an audio output of an audio circuit, system or processing block.
Filter: A device that attenuates certain frequencies while letting other frequencies through. Using a filter to reduce harmonics, changes the timbre or color of the sound.

Frequency Modulation (FM): Using one frequency to modulate another frequency's pitch. When the modulation source is in the audio range, it can be perceived as a change in the timbre or color of the sound. FM can be used to create a wide range of rich and complex sounds and is often described as having a clear and distinctive timbre.

Frequency: Measured in Hz.

Gain: The amount of signal level increase provided by an amplifier stage.

Gate (Synthesizer): A signal used to trigger an event, such as a note or an envelope.

Harmonics: A series of integer-related sine waves at varying levels creating different timbres.
Waveforms (other than a pure sinusoidal) generate various harmonics which help define the character of the sound.

High Pass Filter (LPF): A filter that attenuates lower frequencies below the filter cutoff point, leaving the higher frequencies unaffected.

Invert: To change it to its opposite, e.g. change a positive value becomes negative etc.

Keyboard Tracking: Allows the control signal from received midi notes to adjust another parameter. The Neutron uses keyboard tracking to move the filter cut off frequency relative to the played note.

Kilohertz (kHz): A unit of frequency equal to one thousand cycles of a wave per second.

Level: Used to describe the magnitude of a sound, often relative to an arbitrary reference.

Line Level: A nominal operating level used by audio equipment.

Low Frequency Oscillator (LFO): An oscillator that commonly runs at a very low speed and is used to modulate another parameter.

MIDI (Musical Instrument Digital Interface): A technical standard that describes a protocol, digital interface and connectors and allows a wide variety of electronic musical instruments, computers and other related hardware/software devices to connect and communicate.

MIDI Clock: A clock signal which is broadcast over MIDI to ensure that devices are synchronized. Also known as MIDI Beat Clock or MIDI Timing Clock.

MIDI Message: Data or information transmitted from one MIDI device to another.

MIDI Gate: The MIDI Gate typically controls the note on-off. Mix: The balance of level between one signal and another.

Modulation: The process of controlling one or more properties (destinations) of a signal using another signal (source).

Modulation Wheel (Mod Wheel): A wheel located to the left of a keyboard that allows you to change specified parameters in real-time.

Monitors: Studio quality loudspeakers, providing an accurate representation of the audio signals.

Mono: Signal channel audio.

Monophonic: Only one note can be played at any given time, as there is only a single voice.

Mute: Function that allows a signal to be silenced.

Noise: A circuit that produces white noise.

Note-Priority: Determines which note is played when more notes are held simultaneously than the number of available voices (often: low/high/last).

Octave or Oct: Unit of measurement for pitch. Every time the frequency of a waveform doubles, the pitch increases by one octave.

Oscillator: An electronic device which generates a periodic signal used to form the basis of a synthesizer program.

Output: The signal sent out by a device or process. Also used to describe the physical socket where a signal leaves a device. 26 NEUTRON User Manual

Overdrive: To push to excess or drive too hard.

Parameter: A setting whose value can be changed.

Parametric EQ: A type of EQ that allows all of the parameters of equalization to be changed, including center frequency, boost/cut in gain and bandwidth.

Paraphonic: Is the use of two oscillators independently pitched when more than one MIDI note is played.

Patch: The cables used on modular synthesizers (or synthesizers with modular compatibility) to connect devices together. Patch cables can carry audio, gate or control voltage signals.

Phase: A measurement (in degrees) of the time difference between two waveforms, or between a single waveform and a reference point.

Pitch Bend / Pitch Bend Wheel: Controlling the pitch of a note after it has been played.

Polyphonic: Capable of playing more than one note at once.

Polyphony: The number of notes a polyphonic synthesizer can play simultaneously.

Portamento: An adjustable performance effect that glides or bends the pitch from one note to the next.

Poly-Chaining: A way to connect multiple monophonic synths to play together to create a polyphonic sound.

Power Supply Unit (PSU): The component in a system which is responsible for supplying and managing power.

Psychoacoustics: The study of the perception of sound, that is, how we listen, our psychological responses, and the physiological effects on the human nervous system.

Pulse Wave: Similar to a square wave, but without symmetry. Also known as a "Rectangle Wave."

Pulse Width Modulation (PWM): Modulation of the pulse width (the duty cycle of a pulse wave measured as a percentage). A pulse width of 50% has equal positive and negative sections and is considered a square wave.
Rate: The speed at which a particular device is operating.

Release Time: The fourth and final stage of an ADSR envelope. Specified as the duration of time for an envelope to reach zero after the played key is released.
Resonance (Reso): The emphasis/boost of frequencies around the cut-off frequency.

Reverb: An effect where the ambience of a physical space is simulated.

s: Symbol for "second," a unit of time.

Sample & Hold (S&H): A circuit or function in synthesizers that enables the instantaneous value (voltage) of a waveform to be captured and continues to output that value until the next sample is taken.

Sawtooth: A waveform that combines an instantaneous rise or fall, followed by a gradual linear incline or decline. The name comes from the waveform's similarity to the teeth of a saw.

Semitone: A chromatic half-step. There are twelve semitones in an octave.

Self-oscillation: Occurs when the resonance of a filter is increased to the point where it will begin to generate a sine wave independently of any input.

Signal flow: The path of a signal from one module (or component of a system) to another.

Sinusoidal / Sine Wave: Mathematical description of a smooth waveform that contains only the fundamental frequency and has no additional harmonics. The shape resembles the letter "S" rotated 90 degrees.

Slew Rate: The rate of change of a voltage or control signal.

Soft Clipping: is a technique for adding warm harmonic distortion to your audio.

Square Wave: A symmetrical waveform that combines an instantaneous rise or fall, followed by a positive or negative steady state. The name comes from the waveform's similarity to a square.

Sum: A way to combine signals Sustain Level: The third stage of an ADSR envelope. Specified as "the level an envelope will return to, after the decay stage". The envelope will remain at the sustain level until the key is released.

Synchronization (Sync): Coordination of timing between devices.

Sync (Tempo): A function where a cyclical event such as an LFO is synchronized to a tempo value until the played key is held.

Sync (Oscillator): A function where one oscillator is synchronized to another. The waveform of the slave oscillator is reset whenever the waveform of the master oscillator restarts.

Sync (Key): A function where an event is synchronized to the pressing of a key.

Threshold: This is the level that must be passed before the processing is engaged.

Tone Control: Used to adjust the volumes of various frequency ranges for creative or corrective purposes.

Triggering: Activation of a function, such as the start of a note, envelope, or LFO. Tune / Tuning: The process of adjusting the root pitch of the instrument to a specific reference frequency.

Unipolar: A signal having a single polarity, positive or negative.

Unison: Two or more voices that are playing together at roughly the same pitch.

Universal Serial Bus (USB): A "plug and play" interface that provides a fast connection between a computer and peripherals.

VCA Bias: Controls the minimum amplification present.

Volt (V): A unit of electrical potential differential.

Voltage Controlled Amplifier (VCA): An amplifier whose resultant magnitude is controlled by a voltage.

Voltage Controlled Filter (VCF): A filter whose cut-off frequency can be controlled by a voltage.

Voltage Controlled Oscillator (VCO): An oscillator whose cut-off frequency can be controlled by a voltage.

Voice: A physical embodiment of a complete set of OSC, Envelopes, LFOs and VCF which can play a single note.

Waveform: A repeating signal typically created by an oscillator. A waveform can also be random in the case of noise.

White Noise: A sound that contains every frequency within the range of human hearing (generally from 20 Hz to 20 kHz) in equal amounts.

Width: Sets the pulse width of oscillator square / tone mod waveforms.

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