14. Glossary of Terms
- Advanced Audio Coding (AAC) is a patented audio compression algorithm which
uses a form of lossy data compression. Designed to be the successor
to MP3, AAC generally achieves better sound quality at similar bit
rates. While the .aac extension is sometimes used for AAC-encoded files,
they are typically saved with an .m4a file extension.
- An acoustic fingerprint system built entirely on open-source
technology. It aims to create a free database of user-submitted audio
fingerprints with mapping to the MusicBrainz metadata
database and provide a web service for audio file identification using this
database. For more information, see`<https://acoustid.org/>`_.
- Short for Audio Interchange File Format. High-quality digital audio file
format, similar to .wav files. Contains CD-quality audio stored in a
non-compressed, lossless format. AIFF files generally end with a
.aiff or .aif extension.
- An Application Program Interface (API) is a specification and set of rules
for how software programs interact with each other. In Mixxx, an example of
this is the Sound API that Mixxx uses to communicate with the
Operating System to make use of the soundcards connected to
- A balance control on a mixer allows you to adjust the balance between the
left and right channel. The balance refers to the relative volume of the
corresponding channel in a stereo audio signal.
- In musical notation, a bar (or measure) is a segment of time defined by a
given number of beats. Typically, a piece consists of several bars of the
- A series of markers that point to the location of beats within the track.
Beatgrids are used for advanced mixing functions such as track
sync, precise effects synchronization, looping and accurate
- A mixing technique used to establish a similar tempo with two or more tracks,
making them sound like just one track.
- Files that contain compiled computer code, which was compiled from source
code. Source code, which is usually a bunch of text files, is processed
with a program called a compiler. The compiler then generates a binary,
which is something like an an .exe or a .dll file. By using binaries you
are relieved of the task of having to compile the code by yourself.
- Describe the quality of an audio or video file. For audio data the bitrate
is commonly measured in Kbps. For example, an MP3 audio file that
is compressed at 192 Kbps will have a greater dynamic range and may sound
slightly more clear than the same audio file compressed at 128 Kbps.
- Beats per minute (BPM) is used as a measure of tempo in music.
If you tap your foot to music you are following the “beat”.
If you count how many taps you do in a minute you have calculated the BPM.
- bug report
- Every software has bugs. When you come across a bug in this software, you
should submit a report about it to the developers. They can use this to
identify, replicate and fix the issue.
- CDJ is a term originally used to describe a line of CD players from Pioneer
Electronics. Today CDJ generally refers to DJ CD players that work like a
record player. They allow analog control of music using CDs, usually using
a touch sensitive emulated vinyl control surface.
- Short for compressor/decompressor, a codec is any technology for
compressing and decompressing audio and video data. Some popular
codecs for computer audio include MP3 and Ogg Vorbis.
- An external hardware device that generates and transmits signals to a
computer, usually via USB, to control software with physical controls
other than a mouse and keyboard. Controllers have many uses for music such
as controlling DJ programs like Mixxx. They typically send MIDI
signals but some controllers use HID signals. Many DJs prefer to
control DJ software using physical knobs, faders, and wheels on controllers
instead of using a computer keyboard and mouse.
- The crossfader is a slider that determines how much each deck of audio
contributes to the master output.
- A Cue or Cue point is a reference point in the track usually placed on the
position the DJ wants the track to start at by default. This is useful to
instantly jump to that point without seeking through the track.
- cue sheet
- A cue sheet (or CUE file, CUE sheet, etc.) is a formatted plain text file
which is used to provide index information for a large audio file. For
example, it can be used to tell software extra details about the layout of
a CD to burn.
- Headphone cueing, or just cueing, is listening to the next track you would
like to mix in in your headphones. The audience will not hear what you are
cueing in your headphones. Being able to cue is a crucial aspect to DJing.
- Short for decibels. A Decibel is a logarithmic measurement of sound
level. Whispering is around 25 dB while unbearable sound such as a jet
engine is around 160 db. Rule of thumb: A volume increase of 10 dB is
perceived as twice as loud.
- A deck is like a virtual vinyl turntable. You can load a track into
it and play the track, just like you would put a record on turntable and
- Digital Rights Management (DRM) technologies attempt to control what you
can and can’t do with the media and hardware you’ve purchased. Typically, a
DRM system either encrypts the data so that it can only be accessed in a
way authorized by copyright holders or marks content with a digital
watermark or similar method so that the content can not be freely
distributed. For information about how you can get involved in activism
against DRM, see Defective by Design.
- To cause something to advance at quicker than normal speed. In
terms of audio software that means if you press the fast-forward button
the audio will play with increased speed as long as the button is pressed.
This is useful to seek through a track.
- The opposite of fast-forward. If you press the fast-rewind button
the audio will play in reverse with increased speed as long as the button
- file manager
- A computer program that organizes data files into groups and shows you
where they are when you need to find them again. Popular file managers for
the operating systems Mixxx supports are
Explorer on Windows, Finder on Mac OS X and Nautilus on GNU/Linux.
- Free Lossless Audio Compression (FLAC), a patent-free audio compression
similar to MP3 but lossless (i.e. there is no loss in audio
quality when used). FLAC files generally end with a .flac extension.
- A flanger is an effect that mixes the input signal with a delayed copy of
itself which leads to interferences in the signal and creates a comb-filter
effect. By routing the output of the effect back into the input (feedback),
the effect is enhanced.
- Short for “Graphical User Interface” and is pronounced “gooey”. It refers
to a user interface based on graphics (icons, pictures and menus) instead
of text. In Mixxx, it uses a mouse, keyboard, or MIDI / HID
controllers as input devices.
- head/mix button
- The head/mix button is used to control how much you mix the master
output into your headphone output. This can be very useful when
cueing a track, because you can test out how it sounds when mixed
with the main mix in your headphones, before letting the audience hear the
- headphone button
- The headphone button is used to indicate whether or not you are
pre-listening to a deck or sampler in your headphones.
- headphone output
- The headphone output is what you hear in your headphones.
- Short for for Human Interface Device, a part of the USB specification. It
specifies a device class (a type of computer hardware) for human interface
devices such as keyboards, mice, game controllers, and some DJ
- Similar to the main cue point, a hotcue is a reference point in the
track. DJs usually place hotcues at distinctive positions within a track
such as drops, breaks or kicks and snares. Mixxx supports up to 36 hotcues.
- HSV stands for hue, saturation, and value, and is also often called HSB
(B for brightness). The HSV Color Model represents color in a way more
suited to the human perception of color. For example, the relationships
“stronger than”, “darker than”, and “the opposite of” are easily expressed
in HSV. In contrast, the representation of the hardware-oriented RGB
model is close to what most monitors show.
- Icecast is free and open-source software that allows digital audio
content to be broadcast to and from media player software, enabling the
creation of Internet radio stations. Unlike Shoutcast,
the software provides the ability to stream in free file formats like
Ogg Vorbis and run your own directory server.
- Internet Relay Chat (IRC) is a an online chat network. The Mixxx IRC
channel can be found on the FreeNode IRC Network
in the #mixxx channel.
- Short for kilobits per second. Here used to measure the quality of audio
data. See bitrate
- Short for “musical key” (i.e. C major).
- key lock
- With key lock enabled, the tempo of the track will change but the pitch
remains consistent. When unlocked, the pitch slider will speed up (or slow
down) the track and the pitch will increase (or decrease) along with it.
- kill switch
- A button to turn on and off individual frequency ranges within a channel,
i.e. treble, mid and bass. Useful for effects where the DJ drops a track
out for a period or creates room for a transition.
- LAME is a free software codec used to encode/compress audio into
the lossy MP3 file format.
- Latency refers to a short period of delay (usually measured in milliseconds)
between when an audio signal enters and when it emerges from a system.
Being able to lower the latency as much as possible makes a huge difference
- level meter
- The level meter is used to show the average levels of audio
signals. The level should average around the top of the green region, with
the loudest parts of the music (the transients) briefly going into the
yellow region. If the level meter is in the red, the signal is clipping and
the gain should be turned down.
- Used when describing audio compression algorithms, a lossless algorithm is
one which results in no loss in audio quality when used.
- Used when describing audio compression algorithms, a lossy algorithm is one
which results in a loss in audio quality when used.
- master output
- The master output is the main audio output. It is what your audience hears.
- master sync
- Master sync mode persistently adjusts a track’s tempo and
phase (if quantization is enabled) in order to stay in sync
with other decks that are in master sync mode.
- In general, any piece of information about a music file that Mixxx uses
(e.g. title, artist, album, hotcue locations, loops, etc.). Various file
metadata formats allow information such as the title, artist, album, and
track number to be stored in the audio file itself, see
https://en.wikipedia.org/wiki/ID3 . Mixxx stores additional metadata
about music files in its database, like beatgrid, waveform data,
hotcues, playlists, crates, number of plays, etc.
- Short for for Musical Instrument Digital Interface. A digital
communications language and hardware specification enabling compatible
electronic instruments, sequencers, computers, etc., to communicate with
each other in a network. Most DJ controllers use MIDI
to communicate with computers.
- A patented audio compression algorithm which uses a form of lossy
data compression. It is de-facto standard of digital audio compression for
music. MP3 files generally end with a .mp3 extension.
- A open-source music encyclopedia that collects music metadata and
makes it available to the public. For more information, see
- Ogg Vorbis
- A patent-free audio compression algorithm which uses a form of lossy data
compression. It is designed to provide for efficient streaming and
manipulation of high quality digital audio. Ogg Vorbis files generally end
with a .ogg or .oga extension.
- Generically, open-source refers to a program for which the source code is
available to the public for use and/or modification from its original
design free of charge. Open source code is typically created as a
collaborative effort in which programmers improve upon the code and share
the changes within the community. Open source sprouted in the technological
community as a response to proprietary software owned by corporations. For
more information, see Wikipedia.
- An operating system feature used to draw hardware-accelerated
graphics. Mixxx uses OpenGL to draw the waveform displays and spinning
- operating system
- Your operating system (OS) is the computing environment on your
computer. For example, Windows, Mac OS X, or GNU/Linux are the three
operating systems that Mixxx supports.
- Opus is a totally open, royalty-free, highly versatile lossy audio
codec. The .opus filename extension is recommended.
- PFL or “pre-fader listen” is a fancy word for whether or not you are
“pre-listening” to a deck in your headphones. See also:
- The phase of a track is its position relative to another track. If two
tracks are sync’d to the same tempo and in-phase then they
should be playing so that their beats are aligned.
- pitch bend
- A technique used by DJs that temporarily bends the rate of a track up or
down, usually while a button is held. This technique is usually used to
make micro-adjustments to the synchronization of tracks while
beatmatching. Before digital DJing, this was accomplished by dragging one’s
finger alongside the turntable to slow it down or by twisting the record
spindle to speed it up.
- A podcast is a feed of audio or video files made available for free or for
purchase over the Internet. Podcast clients such as iTunes allow listeners
to subscribe to the feed and automatically download content to their
portable audio players as it becomes available.
- Quantization is the process of aligning notes and other events like loops
or cuepoints so that they start or finish exactly on beats or fractions of
- ramping pitch bend
- Basically identical to the regular pitch bend with the difference
that the pitch changes gradually, instead of all at once. Often uses for
temporary pitch changes. It simulates the effect of touching a turntable
to temporarily slow down or speed up a record.
- The speed at which a track is played back, usually expressed in terms of a
percentage of the speed relative to the tracks normal rate. Often while
mixing, DJs adjust the rates of tracks so that they can play at the same
tempo as other tracks. This allows DJs to beatmix,
and is an essential part of DJing.
- ReplayGain normalizes audio data in a non-destructive way, so the tracks in
your music library don’t all play at different volumes. Audio files are
scanned by a psychoacoustic algorithm to determine the loudness of the
audio data. ReplayGain information is stored as metadata in a
digital audio file in order for the sound to be correctly played at the
right level of loudness.
- Reverse plays a track backwards.
- The RGB color model is an additive color model in which red, green, and
blue light are added together in various ways to reproduce a broad array of
colors. The name of the model comes from the initials of the three additive
primary colors, red, green, and blue.
- Shoutcast is proprietary software that allows digital audio content to be
broadcast to and from media player software, enabling the creation of
Internet radio stations.
- Also known as an audio card, it is an internal computer expansion card or
external expansion device that facilitates the input and output of audio
signals to and from a computer. Today DJ-soundcards are usually connected
via USB and have at least 2 stereo audio outputs to support cueing.
- Sync allows you to automatically adjust a track’s tempo and
phase to be in sync with another deck that is playing.
- The speed of a track measured in bpm.
- Used here in conjunction with vinyl control. A special audio signal
on a control vinyl or control CD (timecode media) that a computer can
listen to in order to determine speed, direction and position of the
- A track is another word for a song.
- Uniform Resource Locator. The address that defines the route to a file on
an Internet server. URLs are typed into a Web browser to access Web pages
and files, and URLs are embedded within the pages themselves as hypertext
links. One example of a URL is http://www.mixxx.org .
- vinyl control
- A method of controlling DJ applications which simulates the traditional
DJing paradigm of two turntables. Using special timecode media,
the DJ application analyzes the timecode signal and simulates the sound and
feel of having your music collection on vinyl.
- A term that refers to the degree of sound intensity or audibility; loudness.
Volume is determined by people’s perception and does not directly correspond
to any physical property of sound.
- Standard digital audio file format used for storing waveform data; allows
audio recordings to be saved with different sampling rates and bitrates;
often saved in a 44.1 KHz, 16-bit, stereo format, which is the standard
format used for CD audio. Wave files are not compressed, and are therefore
lossless. Wave files generally end with a .wav extension.
- waveform overview
- The waveform overview shows the waveform envelope of the entire track, and
is useful because they allow DJs to see breakdowns far in advance.
- waveform summary
- The waveform summary shows the waveform envelope of the track near the
current playback position.