Glossary
Glossary: the words of stem separation, effects and mixing
Stem, acapella, pre-delay, impulse response… Here are the words that come up in our guides and in NAUPLY plugins, explained in one or two sentences, with a link to the guide that goes further.
Stem separation
- Stem
A track that groups one family of sounds from a song: the vocals, the drums, the bass or the other instruments. Added together, the stems give back the complete song.
- Stem separation
Splitting an already mixed song into stems with an AI model. The result is an estimated reconstruction, not the original studio track.
- Multitrack
All the original tracks of a recording (each mic, each instrument). A multitrack contains many more tracks than stems, and only exists with the people who produced the song.
- Acapella
The vocals alone, without any instruments. In a remix, “acapella” means a song's isolated vocal track.
- Instrumental
The song without the lead vocal: all the music, without the singing. It is the opposite of the acapella.
- Karaoke track
An instrumental meant to be sung over, often shown with the lyrics. A vocal / instrumental separation produces one from any audio file.
- Vocal remover
A tool that removes the vocals from a song to keep the instrumental. Modern tools use AI separation rather than the old phase cancellation of the stereo center.
- Backing track
A song with one instrument removed (drums, bass, guitar, vocals) so you can play it yourself over the rest. Also called a “drumless” or “bassless” version.
- Bleed
Traces of one instrument left in another's track after separation, for example cymbals in the vocals. The denser the mix, the more bleed there is.
- Audio to MIDI
Converting an audio recording into MIDI notes. It is much more reliable on a separated stem (a bass, a vocal) than on a full mix.
Tempo, key and practice
- BPM (tempo)
The number of beats per minute in a song. A song at 120 BPM has two beats per second.
- Key
The note and mode (major or minor) a song is built around, for example A minor. Knowing the key helps you transcribe, transpose or mix songs.
- DJ notation (Camelot wheel)
A way of writing keys as a number and a letter (8A, 8B…): two neighboring keys on the wheel blend well.
- Transposition
Raising or lowering every note by the same interval, in semitones, without changing the speed.
- Time-stretching
Speeding up or slowing down a recording without changing its pitch. It is used to practice slowly or to fit a song to another tempo.
- A–B loop
Repeating a chosen passage between a point A and a point B, to practice it or listen to it in detail.
Space and effects
- Reverb (reverberation)
The persistence of a sound in a space after it has stopped, made of thousands of reflections. In mixing, a reverb places a sound in a room, a hall or an imaginary space.
- Pre-delay
The time between the direct sound and the start of the reverb. 10 to 40 ms keep a vocal in front of the space and its lyrics intelligible.
- Decay
How long the reverb tail takes to die out. Short at a fast tempo, longer on a ballad.
- Plate reverb
Originally a vibrating metal plate; today a dense, bright reverb widely used on vocals.
- Algorithmic reverb
A reverb computed by a network of delay lines. All its parameters can be set freely, even beyond what a real room allows.
- Convolution reverb
A reverb that applies to your sound the fingerprint of a real space or device, recorded in an impulse response.
- Impulse response (IR)
A recording of how a space or a device reacts to a very short sound. It loads like an audio file (WAV, AIFF, FLAC) into a convolution reverb.
- Shimmer
A reverb with a pitch shifter in its loop: the tail rises (or falls) by an interval on each pass and forms a luminous pad.
- Delay (echo)
An effect that repeats the sound after a set time. Synced to the tempo, it produces rhythmic echoes.
- Slapback
A single, very short echo (about 80 to 140 ms), with no repeats, that thickens a vocal or a guitar.
- Feedback
The share of the delayed sound sent back to the input of a delay or reverb. The higher it is, the more repeats there are.
- Ping-pong
A delay whose repeats alternate between the left and right of the stereo image.
- Chorus
An effect that blends the sound with a slightly delayed (10 to 30 ms) copy, detuned by modulation, to thicken and widen it.
- Flanger
An effect similar to chorus with a very short delay (under 10 ms) and feedback, which produces a metallic sweep.
- Phaser
An effect that shifts the phase of the sound with filters, then blends it with the original: a few notches move through the spectrum and the sound “swirls”.
- Send and insert
On an insert, the effect processes the whole track. On a send (aux track), you send part of several tracks to it: that is the usual way to use reverb and delay.
Mixing
- Equalizer (EQ)
A tool that raises or lowers the level of certain frequencies to correct or color a sound.
- Low cut (high-pass)
A filter that removes the low end below a chosen frequency. On a vocal, it removes handling noise and rumble.
- Match EQ
An equalizer that compares your sound's spectrum with that of a reference and computes the correction that brings them closer.
- De-esser
A compressor that only acts on the sibilance range (“s”, “sh”) to soften it without dulling the vocal.
- Compressor
A tool that reduces the gap between the loud and quiet passages of a sound, to make it more even.
- Vocal chain
The series of processors applied to a vocal, most often low cut, EQ, de-esser, compressor, then saturation and space.
Software and formats
- Music software (DAW)
The software where you record, arrange and mix a song (digital audio workstation). Plugins load on its tracks.
- Plugin
A software module (effect or instrument) that loads in music software. The most common formats are VST3 and AU.
- VST3
A plugin format supported by most music software, on Mac and PC.
- AU (Audio Unit)
The Mac's own plugin format, supported by macOS music software.
- Standalone app
The version of a plugin that opens on its own, without music software. NAUPLY Stems installs one.
Frequently asked questions
- What is a stem in music?
- A stem is a track that groups one family of sounds from a song: vocals, drums, bass or other instruments. Added together, the stems give back the complete song.
- What is the difference between an acapella and an instrumental?
- The acapella is the vocals alone, without instruments; the instrumental is the music alone, without the vocals. A 2-stem separation gives both from the same song.
- What is the difference between stems and multitracks?
- A multitrack contains all the original tracks of the recording (each mic, each instrument). Stems group those tracks by family, and AI separation can estimate stems from an already mixed song.
- Does AI separation give back the original tracks?
- No. It reconstructs an estimate of each stem. The result is often very clean, sometimes with traces of one instrument in another.
- What is the difference between reverb and delay?
- Reverb simulates a space with thousands of reflections that blend into a tail; delay repeats the sound as distinct echoes, often synced to the tempo.
- What is the difference between VST3 and AU?
- They are two plugin formats. VST3 works on Mac and PC in most music software; AU is Mac-only. NAUPLY plugins come in both formats on Mac.
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