Terms and Acronyms
Eurorack and Synths
Terms, Acronyms, and Definitions
All things that refer to specifically to Eurorack will have an asterisk (*) after the word. Otherwise, they refer to all synths.
- 1V/O – 1 Volt Per Octave, a term used for CV where 1V from the CV input creates a movement of 1 octave range of notes on a keyboard (See Hz/V)
- ADSR – Attack Decay Sustain Release (See Envelope)
- BBD – Bucket Brigade Delay
- BPF – Band-Pass Filter – Filter that allows frequency signals to pass in between a specified low and high cutoff frequency (See Low-Pass and High-Pass Filters) and rejects/attenuates frequencies outside of the band of frequencies specified by the low and high cutoff frequency. This can be also set with a single potentiometer (knob or slider) labeled Q (See Q or Q Factor)
- Bus Board* – Supplies both power and CV between modules usually on either a printed circuit board (Solid Bus Board) which can achieve better isolate power and noise issues (not always), and ribbon cable (See Flying Bus Board)
- CV – Control Voltage
- DCA – Digitally Controlled Amplifier
- DCF – Digitally Controlled Filter
- DCO – Digitally Controlled Oscillator
- Envelope – How a note will play in regards to volume over the course of the key being held and released (See ADSR)
- Flying Bus Board* – Supplies both power and CV between modules (See Bus Board) usually using a ribbon cable
- FM – Frequency Modulation
- Gate – A trigger to open the gate for sound or voltage to flow through (think note on when open/off when closed)
- Granular Synthesis – This method takes a sample (recording) of some length and chops it up into small pieces (grains) of some length (usually very small in milliseconds) and can take those grains and play them back in various fashion (looped, layered, random, etc.)
- HPF – High-Pass Filter – Filter that allows frequency signals to pass above a specified cutoff frequency (See Low-Pass and Band-Pass Filters) and rejects/attenuates frequencies lower than the cutoff frequency
- HP* – Horizontal Pitch – usually used to measure the width of a Eurorack module (1 HP = 5.08mm or 1/5″) – 19″ Rack Standard will usually support 84 HPs of usable space. Many manufacturers make 84 and 104 HP wide racks/enclosures. Each rack/enclosure is 3U in height (similar to 3 RU), so a 6U 104 HP Eurorack enclosure will hold 208 HP of modules in (2) 104 HP rows
- Hz/V – Hertz per Volt – It oscillates on a VCO or LFO input (or any other oscillator) at a number of Hertz per Volt. This is a CV standard still used by Korg, and at one time used by Yamaha. Moog and most Eurorack modules use 1V/O or 1 Volt per Octave, which is not compatible with Hz/V or Hertz per Volt.
- LFO – Low Frequency Oscillator
- LPF – Low-Pass Filter – Filter that allows frequency signals to pass below a specified cutoff frequency (See High-Pass and Band-Pass Filters) and rejects/attenuates frequencies higher than the cutoff frequency
- LPG – Low-Pass Gate – A combination of LPF (Low-Pass Filter) and a VCA (Voltage Controlled Amplifier)
- OSC – Oscillator – Constantly oscillating a set/variable waveform of set/variable frequency interpreted as a signal (it makes the basic tone). It comes in various forms (See DCO and VCO)
- PM – Phase Modulation
- PWM – Pulse Wave Modulation
- Q – Q Factor – Also used in EQ (Equalizers) to set the bandwidth of signal frequencies for cut or boost, and with synths to create a band in BPFs. The lower the Q value, the wider the bandwidth, and the higher the Q value the narrower the bandwidth
- Skiff* – A Eurorack enclosure that is relatively shallow. It may be about 50mm in depth, but every manufacturer is different.
- Skiff-Friendly* – This is a vague term, but looks like any module that is less than 40mm in depth will fit in a Eurorack Skiff (case)
- Sub Oscillator – A dedicated OSC or Oscillator that is one or more octave below the main OSC usually in sync with that oscillator. In general, it is only one octave below, and usually a pulse wave. There are variable Sub OSC that allows for 2 octaves below and/or different waveforms (Sine, Saw or Pulse)
- TZFM – Through Zero Frequency Modulation
- Wavetable Synthesis – A collection of sound waves stored to morph into complex waveforms during playback
- VCA – Voltage Controlled Amplifier – In a nutshell, it is a volume knob. It allows whatever you patch into it become amplified controlled by some potentiometer (knob or slider)
- VCF – Voltage Controlled Filter
- VCO – Voltage Controlled Oscillator
More to come.