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Computer Music Glossary

Hello, and welcome to The $5 Question, a Plasterblog segment where I give tutorials on digital music composing based on questions by my $5+ Patreon readers. Today we have a question from a patron who goes by Unknown.


Are there any formal terms that it’s good to know if you’ve never had formal education in music? Stuff you’d want to know to throw into a search engine if you wanted to look up more information, I mean. Right now I couldn’t even look up things on the subject because I don’t know the right words to use.

I’ll start by saying that there’s not a lot of music theory jargon you need to know in order to write your own computer music, or even to analyze a good deal of modern music. Both tasks can be achieved quite well solely through knowledge of the technical craft. That aside, learning music is usually dumb. For example, a 5 on the AP Music Theory exam awarded me a paltry sum of 2 college credit hours (c.f. Chem AP, which awards 6 for a score of 4, and Spanish AP, which awards 10). Even if you get really good at traditional music, some asshole’s still going to write Faerie’s Aire and Death Waltz, and what will you do then? How will you release the penguins?

Prerequisite Music Theory

If you’re music illiterate, I have good news! Modern composing has eschewed traditional sheet music (though it’s not like art hasn’t been done through sheet music before) in favor of the digital piano roll, which shows the pitch relations and durations of notes much more intuitively. As it turns out, player pianos of the early 20th century are the technological precursor to MIDI, the essential technology of computer music which I describe in more detail below. Even if you’ve never used a DAW before, you might be familiar with the piano roll interface through “MIDI art videos” like this artful rendition of Shrek , or Andrew Huang’s GLORIOUS MIDI UNICORN:

Thanks to the piano roll, you can get away with cursory knowledge of pitch and rhythm to start out with. Can you divide by four? Good enough! With time and musical training you can generate more complex rhythms in uncommon time signatures, and tackle different note lengths like triplets and even (gasp) duplets.

Having a sense of natural-sounding chord progressions will help your music sound better, and you may already have a basic instinct just from listening to music regularly. Even without one, you can easily learn and rely on simple progressions as a crutch, like I-vi-IV-V or I-V-vi-IV. Oh. Uh. Maybe Google “Roman numeral analysis” if you didn’t understand that. Should take like 30 seconds.

You should also learn the difference between major and natural minor scales (as well as harmonic and melodic minor scales, the pentatonic scale, and modes if you want to get fancy). Intervals are incredibly important to forming interesting melodies and harmonies. Of course if your intent is to write classical Indian music, you can throw all this advice in the trash and get to practicing your ragas.

Anyway, I won’t spend time defining basic music theory concepts here, because it’s a lot easier to get basic music training online with very simple searches. I will, however, go into length regarding music software terms you might encounter, in no particular order:

Music software terms

Here is what will help you build an arsenal of music-making tools:

DAW – Digital audio workstation, aka the software you write music in. The DAW is a MIDI sequencer, VST host, and (often) audio recorder rolled into one. Garageband and FL Studio are arguably the most well-known DAWs on the market.

VST – Virtual Studio Technology. VST2 is Steinberg’s proprietary software format for virtual instruments and effect plug-ins, and the one you will find most often. There are other propietary formats you’ll want to be familiar with depending on your DAW, such as Logic/GarageBand’s Audio Unit (AU) or the Avid Audio eXtension (AAX) for Pro Tools. The successor to this technology, VST3, already exists, but isn’t as widely adapted as VST2. Sometimes VSTi is used to specifically refer to VST instruments.

SoundFont – A file which maps various midi notes to audio samples or GM wavetable sounds. SoundFont is a proprietary format by Creative Labs which is usually colloquialized as the lowercase soundfont, not unlike q-tips or kleenix. The standard SoundFont 2.04 format is .sf2, but there’s also the open format .sfz and Muse Score’s ogg-based .sf3. SoundFonts are often low-quality and artificial-sounding compared to their virtual instrument counterparts, but are a popular choice for emulating the sounds of 16-bit games. Most soundfonts online can be downloaded for free, though often lack any guarantee as to their copyright viability. The legal status of game-based soundfonts remains contentious, but if Toby Fox can get away with it, then so can you!

Kontakt libraries/instruments – Native Instruments’ Kontakt (version 5 as of this time of writing) is a popular software sampler. Due to its high-performance coding engine, built-in real-time effects, routing features, and ease of use, Kontakt has become an increasingly popular choice for virtual instrument developers, especially for instrument ensembles or those recorded through a multi-mic setup. Kontakt instruments are available as NI-licensed libraries (.nicnt files), which are nearly always commercial and require activation through the earth-shatteringly terrible NI Service Center,  and unlicensed 3rd-party instruments/multis (.nki and .nkm files). The free version of Kontakt, called Kontakt Player, can only play unlicensed instruments for 15 minutes at a time before the sampler must be restarted. There are other large-scale samplers with a variety of first- and third-party libraries, such as SampleTank or UVI Workstation, but Kontakt is arguably the most popular, with the biggest selection.

** To be clear, Kontakt instruments and soundfonts aren’t VST alternatives, per se. Kontakt 5 loads as a standalone application or in your DAW as a VST, and SoundFonts are loaded using a SoundFont player VST. So, if you wanted to use a saxophone, you might use Kontakt as a VST and then load up Embertone’s Sensual Sax, or you could use DVS Saxophone by itself, or you could use Sforzando as a VST and load this Robbie Rotten saxophone soundfont.

Samples – High quality (usually .wav) recordings of an instrument’s or ensemble’s individual notes, created for the purpose of digital music creation. Samples are the backbone of any virtual instrument, and high production-value commercial libraries will often boast several gigabytes worth of them. Drum and percussion samples are usually referred to as oneshots. There are many free sample packs available online if you’re in the market to assemble your own drum kits.

Loops – Musical phrases featuring one or more instruments which can be seamlessly repeated. Loops, free or commercial, are nearly always royalty-free, and meant to be used in conjunction with other loops or your own music in the making of a song. For example, Modal Shanghai uses this EDM drum loop as the beat. I’m doing more of my own drums these days, I promise!

Rompler – A rompler is a type of sampler that comes preloaded with sounds and lacks the functionality allowing users to import their own. Some samplers can be considered romplers but not vice versa. Rompler can be a more useful term when searching for free instrument collections or drum machines, like Orion Sound Module or Beatfactory Drums.

Functional terms

Here are the terms you should know to get the most out of your virtual instruments. You might see some of them on soundware sites to describe virtual instrument products and their features. This section delves into the historical and technical side of things, but you really only need to know that these concepts exist.

MIDI – Acronym for Musical Instrument Digital Interface. MIDI is the basic technology behind computer music — it is essentially digital sheet music, and carries the note and performance data which virtual instruments use to generate sound. In addition to note data, each MIDI message consists of an 8-bit status byte and 1-2 data bytes. A status byte can be either a System Message or one of the seven types of Channel Voice Messages: Note On (key number/velocity), Note Off (key number/release velocity), Polyphonic Aftertouch/Key Pressure, Channel Aftertouch/Key Pressure, Pitch Bend, Program Change, and Control Change. To the non-musical internet, MIDI is sometimes conflated with the sounds of your computer’s default General MIDI synth, CASIO keyboards, or the general lameness that very simple MIDI files inspire.

Velocity – How hard the note is struck (or released), specified as a value from 0-127, with 127 being the loudest or most intense. Depending on the instrument, velocity may only effect the volume of the notes, or it may completely change the sound of the attack/transient. Note off velocity is rarely ever used.

Mod Wheel – By default, the mod wheel (CC 1) modulates the instrument’s pitch, creating an artificial-sounding vibrato. Most synths allow you to control a parameter of your choosing with the mod wheel. The mod wheel can be found next to the pitch wheel on most MIDI keyboards, although the pitch wheel is designed to snap back to its default position on release.

Aftertouch – Traditionally, aftertouch refers to the distance a piano key is depressed after initial contact is made between the jack toe and the let-off button (nos. 18 and 19 on this diagram), or the difference between the key’s initial contact and its full range of motion. The piano keyboard remains the basis of the skeuomorphic interfaces of soft synths and MIDI sequencers, so this term has been applied to the data sent as the key is further depressed. Aftertouch can be used to further control certain parameters, like vibrato.

An options interface with dropdown menus for selecting a CC number for various features, such as bow position and vibrato speed. There's also a message noting CC ranges reserved by the instrument's script.
This options page on the Friedlander Violin allows you to set custom CCs and keyswitches for certain features.

CC – Short for crowd control Continuous Controller/Control Change. CCs are used to assign MIDI notes certain performance data that aren’t covered by the other 6 Channel Voice Messages. For example, CC 11 controls expresion and CC 64 toggles sustain pedal. There are 127 CCs in all, which can be set to values from 0-127 (127 is the largest signed 8-bit value). The terms “continuous controller” and “control change” are often used interchangeably (if at all — usually they’re just called CC). Official MIDI specifications now seem to prefer the latter. Many instruments and synths will allow you to assign certain parameters to CCs, though certain ranges are reserved for internal use. Here’s a list of all the default CC assignments.

The most important takeaway from CCs is that they can be used to imitate the nuance of live musical performance.

Keyswitching – Libraries with a lot of built-in articulations and features often allow you to switch between desired play styles and other options using notes below the instrument’s range, usually in octaves -2 through 0. Keyswitching can be used in addition to or as an alternative for custom-set CCs in some cases.

Round robin – (sometimes RR) refers to the additional samples sometimes included to allow repetition of the same note without sounding robotic, or to the sample-switching feature itself. For example, a library with three samples for every pitch might boast x3 Round Robin. Neighbor-borrowing Round Robin means that the sample for a different pitch will be used and tuned to the desired pitch to achieve the same effect.

DI – Direct Input, used with electric guitar libraries to refer to the clean guitar signal without the amp/cabinet/scream pedal effects on.

Polyphonic/Monophonic – Refers to the capability of an instrument/synth to sound two or more notes simultaneously. While there are synths that are designed to be purely mono (such as delamancha’s PULS or TWEAKBENCH’s monomate or Tekit Audio’s Genobazz), most synths and instruments will be polyphonic or offer the option to toggle between the two. The advantage of monophony is that it allows an instrument to be played legato/portamento and allows synths, like Synapse Audio’s DUNE, to have a really wide face-melting sound.

A Kontakt instrument interface shows various articulation options for a solo horn, of which "staccato" has been selected.
Various articulations for a solo horn in Bravura Scoring Brass.

Articulation – Many instruments can be played a variety of ways (thanks for reading my blog, I know I’m super helpful!!). For example, a violin could be played legato, staccato, and pizzicato, though not all at once because that sounds dangerous. These play styles are referred to as articulations. Here are some you might encounter:

  • Sustain – long notes, which usually (but not always) loop so they can be held indefinitely.
  • Legato – sustains recorded/programmed to sound as though they are realistically being played as one phrase.
  • Staccato – short, detached notes.
  • Spiccato – similar to staccato, but the bow is bounced on the strings, producing a nuanced sound.
  • Pizzicato – notes played by plucking, rather than bowing, a string instrument. The opposite of pizzicato is arco, but you won’t see this in digital music composition, only on sheet music, so I included it merely as a fun fact.
  • Sforzando – notes that are suddenly VERY LOUD. Similar to fortepiano, only fortepiano starts very loud and becomes very soft.
  • Marcato – accented notes…
  • Tenuto – notes held out to their full length and then some. Tenuto can also indicate an accent depending on the context.
  • Muted – notes produced by limiting the resonance of the instrument in some form, e.g. with the palm on the strings of a guitar or by shoving a metal cone into your trumpet. Bowed string instruments can also be muted by putting a piece of rubber on or near the bridge, but no one has ever desired or produced this sound in a sample library to my knowledge.
  • Power chords – a guitar chord consisting of the root and the fifth, or less commonly, inverted to produce a perfect fourth. Sometimes the root is also doubled an octave higher. Playing power chords makes you sound cool.
  • Tremolo – sound produced by playing the note repeatedly in rapid succession. A similar effect can be produced in brass and woodwind through flutter tongue or double tongue.
  • Flutter tongue – a buzzing or growling note produced on brass and woodwind when the player flutters their tongue.
  • Trill – rapid modulation between two notes. Usually instruments will include an option for major/whole step and minor/half step trills.
  • Harmonics – a high, squeaky, isolated overtone produced by lightly pressing down on the string. I’ve only seen this included in guitar libraries, though bowed instruments can produce them as well.
  • Slur – two or more notes which are played without changing direction of or stopping movement of the bow. Comparable to hammer-ons and pull-offs on the guitar, in which a finger is added or removed to change notes without plucking the string a second time.

Want to hear a bad song we had to sing in AP Music Theory? Ok, here goes:

♫ Long and thin, legato is like spaghetti. Short, and chopped in tiny pieces, staccato is like macaroni. ♫

There are no musical notes to this song; it is merely chanted aloud to lousy CD accompaniment to drown out the death throes of music theory students everywhere. I do not know who wrote this song, but mark my words: I will find and destroy them.

Portamento – From the Italian word for “carrying,” portamento refers to a note which slides up or down to its pitch, or ends with a pitch slide. This can be achieved by sliding from one note to another, but with some libraries the effect can be achieved on just one pitch by using a ghost note. High-end solo instruments might have a keyswitch to trigger portamento, but the basic effect can also be achieved using the pitch wheel.

Dressed/naked – Descriptor indicating whether a sound demo features additional instruments and effects (dressed) or only the instrument in question (naked). The Stroh Violin has multiple demos of each kind.

Synth Terms

A lot of genres require at least a passing familiarity with software synths. Plus, the more you know about how synths work, the more mileage you can get out of the wide variety of free synths on the net. Then you can spend your hard-earned money on more important things, like ice cream or Plasterbrain’s discography.

If you’re interested in the different kinds of synths you might discover — subtractive, additive, FM, etc. — Yamaha has a bizarrely formatted presentation (it’s like an HTML slideshow designed by someone who really misses Flash) on the different types of synthesis.

Oscillator – Signal generator in a synth which creates a periodic sonic waveform. Synth waveforms are more basic than the waves created by actual instruments. Read on as I attempt to describe their various types:

A synth interface showing an expanded dropdown menu for synth waveforms. Noise has been selected.
TAL-Noisemaker, a virtual analog synth, offers five kinds of waveform for its second oscillator, including noise.
  • Pulse wave – a transient wave with a flat crest and trough, representing an on state (amplitude of 1) and an off state (amplitude of 0) — hence the wave “pulses.” Pulse waves are described by their duty cycle, the ratio of time spent in the on state to the entire period of the wave. For example, a pulse wave with a 12.5% duty cycle is “on” for 1/8th of the total period. Bergentrückung has either a 25% or 75% cycle (they’re really hard to tell apart in a polyphonic context), while Heartbreak uses a 12.5% cycle.
    • Square wave – a type of pulse wave with a 50% duty cycle. You can hear a square wave in this incredibly relevant and accessible example from Senpai Club. Pathetic House also uses a square wave.
  • Saw wave – a wave with sharp, sawtooth crests shaped like a right triangle. Saws are the bread and butter of Hi-NRG, Eurobeat, EDM, and Para Para. Here’s a song I liked in 2011. There’s nothing that says “get up and dance” quite like a saw wave! Oh and I guess I should be consistent with my Undertale examples… Death by Glamour!
  • Sine wave – a wave shaped like a sinusoid. Take a math class sometime, nerd! Sine waves aren’t part of the retro trifecta but they sound like whistling and slide very nicely.
  • Triangle wave – a wave with sharp, triangular crests which lack the vertical descent of a sawtooth. Triangle waves make great chiptune basses. Can you hear the triangle bass in Spider Dance?
  • Noise – not exactly a simple repeating waveform — it’s amplitude is modulated randomly — but you’ll often see it included in synths with the other waveforms.
    • You probably already know that noise signals can be described by different colors (most commonly white, pink, or brown) based on how its power (in dB) scales with its frequency (in Hz)
    • In the case of the NES 2A03 sound channels, noise comprises a repeating sequence of 93 or 32767 random bits. Matt Montag, who created the Nintendo VST, compares them to “a square wave with a continuously-varying random pulse width.” 32767 bits is the highest signed 16-bit value, and 93… uh… I’m not sure why they picked 93. The robotic-sounding intro of Metal Crusher is all sounds using 93-bit noise.
  • Wavetable synths also use a selection of arbitrary waveforms. Sample-based synths, like iZotope’s Iris 2, generate synth based on audio samples. Chiptune emulators may also have a DPCM/PCM channel, which can be used to play back samples, e.g. for drumkits.

Composer Zoe Blade shows what some of these waveforms look like on her incredibly cute site.

Studying early video game music is a great way to get acquainted with some of these basic waveforms and the physics behind them. For further reading, check out Classical Gaming, Retro Game Audio, and Maestro Mario by Andrew Schartmann.

An interface showing LFO 2, set to modulate the rate of LFO 1, and LFO 3, set to modulate the rate of LFO 2.
In VTX’s VSTron, you can modify the rate of one LFO using another. This sounds… awful.

LFO – Stands for Low Frequency Oscillator, a signal at 20 Hz or less which is used to modulate a synth in a rhythmic fashion. LFOs can be combined with other LFOs and envelopes for even more drastically modulated effects.

ADSR – Shorthand for attack, decay, sustain, and release, the four different stages of a note from keypress to key release. Synths use ADSR as parameters for volume and filter envelopes, though sometimes virtual instruments will have them for volume as well. Unlike a lot of wibbly wobbly sound magic, ADSR is fairly simple to understand. For example, here’s how the sound might change when you alter the time for each stage.

    • A long attack will cause the note to fade in, rather than beginning right when the key is pressed.
A VST interface with four knobs, labeled Attack, Decay, Sustain, and Release. The knobs are situated under the heading "Envelope."
The ADSR knobs in Etherealwinds Harp 2.
  • A short decay will cause the note to quickly change from the attack volume to the sustain volume, which is usually softer.
  • A short sustain will end the note even if the key is still being held.
  • A long release will cause the note to hang even after the key is released.

Filters – Allow only certain ranges of sound to pass through.

  • High-pass filters (HPF) allow only sounds above a given cutoff frequency.
  • Low-pass filters (LPF) allow only sounds below a given cutoff frequency.
  • Band-pass filters (BPF) allow only sounds within a certain frequency range.
  • All-pass filters allow all frequencies to pass, but change their phases. Here’s a wibbly-wobbly physics explanation of the AP filter. Phaser plug-ins make use of AP filters.

Musician Yala explains the features of synth in much more detail here.

Audio terms

These are words to know when you’re interested in mixing, mastering, or adding effects to your music. Most of the effects mentioned here are much more complex than I make them sound, so they’re worth looking into further if you want to become an audio mastering master. I am not an audio mastering master, in case that’s not extremely obvious.

EQ – Short for equalizer or equalization. Equalizers are used to cut or boost of frequency ranges, or bands. For example, you might cut around 60-100 Hz if your bass sounds too muddy. You can find guides on EQ for just about every instrument!

Compressor – Device used to reduce a sound’s dynamic range by lowering the loudest points by the specified level of gain reduction and amplifying the softest points.

Limiter – A limiter is a compressor but cooler, and you use it more often on an entire mix rather than just one track or submix.

Exciter – An effect that “brightens” sound quality through harmonic distortion, eq, and phase modulation.

Flanger – Alters a sound by combining it with a phase-shifted version of itself. The result, especially used on a drumkit, sounds kind of like when those jets pass over your head on that corkscrew towards the end of Radical Highway. You know the sound? No? Just me? Flangers can also be used to produce that one cheesy clean electric guitar effect. Unrelated side note — this guy… is so chill…

Phaser – Yeah alright I’m just gonna link you to Johnny DeMarco again.

Chorus – Similar to flangers in that it combines the original sound with one or more delayed and pitch-modulated versions of itself. This effect is achieved using LFOs, usually with a faster rate than those of a flanger, in order to emulate human vibrato. The aim of the effect is to simulate the effect of multiple instruments playing as one, as in a choir, though it can be used on much more than just vocal tracks. The chorus effect gives audio a wide and shimmery sound.

De-Esser – Used to remove sibilance from harsh-sounding vocals.

Reverb – a sound produced after the initial sound reflects on, and is absorbed by, surfaces in the acoustic space. In our context, reverb refers to the impression of this phenomenon created by a reverb plug-in or built-in effect. Reverb plug-ins can emulate real life spaces using impulse responses (IR).

Delay – the effect of a sound repeating itself at increasingly lower volumes before fading out entirely. Delay is essentially an echo, but unlike reverb isn’t necessarily applied to imitate a real life echo in a cave or something. That would be dumb. Delay and reverb plug-ins refer to the unprocessed audio as the “dry” signal, and the audio with an effect on it as the “wet” signal. Usually you can adjust the gain levels on the two if you don’t want a fully wet sound.

Panning – an audio signal’s bias towards the left or right speaker. For example, a sound panned hard left will seem to be coming from your left-hand side, where as a sound panned center will come from both sides equally. Panning and volume are the most basic parameters of an audio track.

Stereo Imaging – The use of panning, volume, eq, delay, etc. to give the impression that an instrument or track resides somewhere in physical space. Achieving complex stereo images is a matter of psychoacoustics.

There are numerous other, though less common, effects you might be interested in, especially if you plan on replicating classic sounds by [insert favorite late 20th century band here]: arpeggiators, ring modulators, transient shapers, noise gates, tape and tube saturation, distortion, bit crushers, virtual amps and cabinets, tube screamers, wah-wah pedals, gating and side-chaining plugins, harmonizers, vocoders, pitch-correction software, octave reverb, tape stops… the list goes on.

If you have any information I missed or thoughts to add, leave a comment below.

Want to hear more about a specific topic on electronic music or listen to me ramble more about how much I hate AP Music Theory? Donate $5 or more to the Plasterbrain Patreon and submit your question!

Post Author: plaster

Winner of Miss Best Effort seven years and counting, Plasterbrain spends her days pretending to code, writing music, and third bullet point. Her top three first dates would be hunting for slugs, writing fanfiction about Hanzo, and a joint Powerpoint presentation. Oh wait wait wait! Can I add a fourth? The fourth is Neopets.

One thought on “Computer Music Glossary


    (November 18, 2017 - 5:11 am)

    Thank you for this post, it is really amazing. As I was reading I kept thinking “hmm, and that is probably the end”, but it kept going and going with lots of info.
    I think there is a bug with the website. It highlights all link in a paragraph if mouse over one of them (the same with links changing color after you click). This only happens in bullet point lists.

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