14. Glossary of Terms

AAC
Advanced Audio Coding (AAC) is a patented audio compression algorithm which uses a form of lossy data compression. Designed to be the successor 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.
AIFF
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.
balance
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.
bar
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 same length.
beatgrid
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 BPM representation.
beatmatching
A mixing technique used to establish a similar tempo with two or more tracks, making them sound like just one track.
binaries
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.
bitrate
Describe the quality of an audio or video file. For audio data the bitrate is commonly measured 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.
BPM
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
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.
codec
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.
crossfader
The crossfader is a slider that determines how much each deck of audio contributes to the master output.
cue
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.
cueing
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.
db
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.
deck
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 play it.
DRM
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.
fast-forward
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 trough a track.
fast-rewind
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 is pressed.
file manager
Is 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.
FLAC
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.
flanger
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.
GUI
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 track.
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.
HID
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 and game controllers.
HID controller
An external hardware device that generates and transmits HID data to HID-enabled hardware or software (e.g. Mixxx). Connected to your computer via USB, HID controllers allow you to control audio applications among others. Many DJs prefer to control DJ software using physical knobs, faders, and wheels instead of using a computer keyboard. Besides the known DJ controllers also keyboards, mice and game controllers are some of the most popular HID devices. Compared to MIDI it also allows use of advanced features such as those found on modern CDJs, e.g. display screens and high-resolution jogwheels.
hotcue
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
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
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.
IRC
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.
kbps
Short for kilobits per second. Here used to measure the quality of audio data. See bitrate
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
LAME is a free software codec used to encode/compress audio into the lossy MP3 file format.
latency
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 in responsiveness.
lossless
Used when describing audio compression algorithms, a lossless algorithm is one which results in no loss in audio quality when used.
lossy
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.
metadata
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.
MIDI
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.
MIDI controller
An external hardware device that generates and transmits MIDI data to MIDI-enabled hardware or software (e.g. Mixxx). Usually connected to your computer via USB, MIDI controllers allow you to control audio applications among others. Many DJs prefer to control DJ software using physical knobs, faders, and wheels instead of using a computer keyboard.
MP3
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.
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.
open-source
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.
OpenGL
An operating system feature used to draw hardware-accelerated graphics. Mixxx uses OpenGL to draw the waveform displays and spinning vinyl widgets.
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.
PFL
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: headphone button.
phase
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.
podcast
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
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 beats.
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.
rate
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
ReplayGain normalizes audio data in a non-destructive way, so the tracks in your music library dont all play at different volume. Audio files are scanned by an 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
Reverse plays a track backwards.
RGB
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
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.
soundcard
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
Sync allows you to automatically adjust a track’s tempo and phase to be in sync with another deck that is playing.
tempo
The speed of a track measured in bpm.
timecode
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 playback.
track
A track is another word for a song.
url
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.
volume
A term that refers to the degree of sound intensity or audibility; loudness. A volume control is used to adjust the output gain setting.
vu meter
The volume unit (VU) meter is used to show the relative levels of audio signals and is subdivided across channels. Basically it represents how ‘loud’ a sound from a channel is.
WAV
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 postition.