Club DJ (left); Radio DJ (right)

A disc jockey, more commonly abbreviated as DJ, is a person who plays recorded music for an audience. Most common types of DJs include radio DJs, club DJs, who work at a nightclub or music festival, mobile DJs, who are hired to work at public and private events (weddings, parties, festivals), and turntablists who use record players, usually turntables, to manipulate sounds on phonograph records. Originally, the "disc" in "disc jockey" referred to vinyl records, but nowadays DJ is used as an all-encompassing term to also describe persons who mix music from other recording media such as cassettes, CDs or digital audio files on a CDJ, controller, or even a laptop. DJs may adopt the title "DJ" in front of their real names, adopted pseudonyms, or stage names.

DJs use audio equipment that can play at least two sources of recorded music simultaneously and mix them together to create seamless transitions between recordings and develop unique mixes of songs. Often, this involves aligning the beats of the music sources so their rhythms and tempos do not clash when played together and to enable a smooth transition from one song to another. DJs often use specialized DJ mixers, small audio mixers with crossfader and cue functions to blend or transition from one song to another. Mixers are also used to pre-listen to sources of recorded music in headphones and adjust upcoming tracks to mix with currently playing music. DJ software can be used with a DJ controller device to mix audio files on a computer instead of a console mixer. DJs may also use a microphone to speak to the audience; effects units such as reverb to create sound effects and electronic musical instruments such as drum machines and synthesizers.

Role

Avicii at work in Paris in 2011

Originally, the "disc" in "disc jockey" referred to gramophone records, but now "DJ" is used as an all-encompassing term to describe someone who mixes recorded music from any source, including vinyl records, cassettes, CDs, or digital audio files stored on USB stick or laptop. DJs typically perform for a live audience in a nightclub or dance club or a TV, radio broadcast audience, or an online radio audience. DJs also create mixes, remixes and tracks that are recorded for later sale and distribution. In hip hop music, DJs may create beats, using percussion breaks, basslines and other musical content sampled from pre-existing records. In hip hop, rappers and MCs use these beats to rap over. Some DJs adopt the title "DJ" as part of their names (e.g., DJ Jazzy Jeff, DJ Qbert, DJ Shadow and DJ Yoda). Professional DJs often specialize in a specific genre of music, such as techno, house or hip hop music. DJs typically have an extensive knowledge about the music they specialize in. Many DJs are avid music collectors of vintage, rare or obscure tracks and records.

Types

Radio DJs

Radio DJs or radio personalities introduce and play music broadcast on AM, FM, digital or Internet radio stations.

Club DJs

DJ Pete Rock performing at Rahzel and Friends - Brooklyn Bowl, 2016

Club DJs, commonly referred as DJs in general, play music at musical events, such as parties at music venues or bars, music festivals, corporate and private events. Typically, club DJs mix music recordings from two or more sources using different mixing techniques in order to produce non-stopping flow of music.

One key technique used for seamlessly transitioning from one song to another is beatmatching. A DJ who mostly plays and mixes one specific music genre is often given the title of that genre; for example, a DJ who plays hip hop music is called a hip hop DJ, a DJ who plays house music is a house DJ, a DJ who plays techno is called a techno DJ, and so on.

The quality of a DJ performance (often called a DJ mix or DJ set) consists of two main features: technical skills, or how well can DJ operate the equipment and produce smooth transitions between two or more recordings and a playlist; and the ability of a DJ to select most suitable recordings, also known as "reading the crowd".[1]

Hip hop DJs

DJ Kool Herc, Grandmaster Flash, and Afrika Bambaataa were members of block party at South Bronx. Kool Herc played records such as James Brown's "Give It Up or Turnit a Loose", Jimmy Castor's "It's Just Begun" and Booker T. & the M.G.'s' "Melting Pot"[2]. Herc played Incredible Bong Band "Bongo rock", "Apach", and UK rock band Babe Ruth "The Mexican" also. With Bronx clubs struggling with street gangs, uptown DJs catering to an older disco crowd with different aspirations, and commercial radio also catering to a demographic distinct from teenagers in the Bronx, Herc's parties had a ready-made audience.[3][4][5]

DJ Kool Herc developed the style that was the blueprint for hip hop music. Herc used the record to focus on a short, heavily percussive part in it: the "break". Since this part of the record was the one the dancers liked best, Herc isolated the break and prolonged it by changing between two record players. As one record reached the end of the break, he cued a second record back to the beginning of the break, which allowed him to extend a relatively short section of music into "five-minute loop of fury".[6] This innovation had its roots in what Herc called "The Merry-Go-Round," a technique by which the deejay switched from break to break at the height of the party. This technique is specifically called "The Merry-Go-Round" because according to Herc, it takes one "back and forth with no slack."[7]

Reggae Deejays

In Jamaican music, a deejay (DJ) is a reggae or dancehall musician who sings and raps ("toasts") to an instrumental (or riddim). U Roy, Big Youth, and I Roy were famous deejays in Jamaica.

Turntablists

Turntablists, also called battle DJs, use turntables and DJ mixer to manipulate recorded sounds in order to produce new music. In essence, they use DJ equipment as a musical instrument. The most known turntablist technique is scratching. Turntablists often participate in DJ contests like DMC World DJ Championships and Red Bull 3Style.[8]

Residents

A resident DJ performs at a venue on a regular basis or permanently.[9][10][11] They would perform regularly (typically under an agreement) in a particular discotheque, a particular club, a particular event, or a particular broadcasting station.[12][13][14] Residents have a decisive influence on the club or a series of events.[15] Per agreement with the management or company, the DJ would have to perform under agreed times and dates.[10][16] Typically, DJs perform as residents for two or three times in a week, for example, on Friday and Saturday. Also, DJs who make a steady income from a venue, are also considered resident DJs.[17][18]

Examples for resident DJs are:[19][20]

  • Alfredo Fiorito, Richie Hawtin, Sven Väth - Amnesia, Ibiza(mecca for hippie)[21]
  • Martin Garrix - Hï Ibiza, Ibiza
  • Larry Levan - Paradise Garage, New York City, USA
  • David Mancuso - The Loft, New York City, USA
  • Tiësto, Deadmau5, Calvin Harris - Hakkasan, Las Vegas, USA
  • Kaskade - Encore Beach Club, Las Vegas, USA
  • Dom Chung - UK
  • Ben Klock, Marcel Dettmann, Tama Sumo - Berghain, Berlin, Germany
    • Mobile DJs - DJs with their own portable audio sound systems who specialize in performing at gatherings such as block parties, street fairs, taverns, weddings, birthdays, school and corporate events. Mobile DJs may also offer lighting packages and video systems.[22]
    • Producer DJs - DJs who create remixes of popular club hits, completely original tracks, or transition friendly versions of tracks which extend the start and end of a song. Producer DJ often have their work featured on online DJ record pools.[23]
    • DJanes - a term describing female DJs used in countries such as Germany that employ grammatical gender in their languages.[24]
    • Celebrity DJs - widely known celebrities performing as DJs.[25]
    • Bedroom DJs - a general term for DJs performing at home, usually recording their sets and posting them online.

      DJs use equipment that enables them to play multiple sources of recorded music and mix them to create seamless transitions and unique arrangements of songs. An important tool for DJs is the specialized DJ mixer, a small audio mixer with a crossfader and cue functions. The crossfader enables the DJ to blend or transition from one song to another. The cue knobs or switches allow the DJ to "listen" to a source of recorded music in headphones before playing it for the live club or broadcast audience. Previewing the music in headphones helps the DJ pick the next track they want to play, cue up the track to the desired starting location, and align the two tracks' beats in traditional situations where auto sync technology is not being used. This process ensures that the selected song will mix well with the currently playing music. DJs may align the beats of the music sources so their rhythms do not clash when they are played together to help create a smooth transition from one song to another. Other equipment may include a microphone, effects units such as reverb, and electronic musical instruments such as drum machines and synthesizers.

      DJ Spooky at the Sundance Film Festival in 2003, using two Technics SL-1200 turntables and a DJ mixer

      As music technology has progressed, DJs have adopted different types of equipment to play and mix music, all of which are still commonly used. Traditionally, DJs used two turntables plugged into a DJ mixer to mix music on vinyl records. As compact discs became popular media for publishing music, specialized high quality CD players known as CDJs were developed for DJs. CDJs can take the place of turntables or be used together with turntables. Many CDJs can now play digital music files from USB flash drives or SD cards in addition to CDs. With the spread of portable laptop, tablet, and smartphone computers, DJs began using software together with specialized sound cards and DJ controller hardware. DJ software can be used in conjunction with a hardware DJ mixer or be used instead of a hardware mixer.

      Turntables

      Turntables allow DJs to play vinyl records. By adjusting the playback speed of the turntable, either by adjusting the speed knob, or by manipulating the platter (e.g., by slowing down the platter by putting a finger gently along the side), DJs can match the tempos of different records so their rhythms can be played together at the same time without clashing or make a smooth, seamless transition from one song to another. This technique is known as beatmatching. DJs typically replace the rubber mat on turntables that keeps the record moving in sync with the turntable with a slipmat that facilitates manipulating the playback of the record by hand. With the slipmat, the DJ can stop or slow down the record while the turntable is still spinning. Direct-drive turntables are the type preferred by DJs, with the Technics SL-1200 being the most popular model of turntables for DJs. Belt-drive turntables are less expensive, but they are not suitable for turntablism and DJing, because the belt-drive motor does not like being slowed down, as it can stretch out the belt (or in most cases, snap the belt, thus damaging the whole turntable). Some DJs, most commonly those who play hip hop music, go beyond merely mixing records and use turntables as musical instruments for scratching, beat juggling, and other turntablism techniques.

      CDJs

      CDJs are high quality digital media players made for DJing. They often have large jog wheels and pitch controls to allow DJs to manipulate the playback of digital files for beatmatching similar to how DJs manipulate vinyl records on turntables. CDJs often have features such as loops and waveform displays similar to DJ software. Originally designed to play music from compact discs, they now can play digital music files stored on USB flash drives and SD cards. Some CDJs can also connect to a computer running DJ software to act as a DJ controller.

      DJ mixers

      A Numark DM2002X Pro Master DJ mixer. This three channel mixer can have up to three input sound sources. The gain control knobs and equalization control knobs allow the volume and tone of each sound source to be adjusted. The vertical faders allow for further adjustment of the volume of each sound source. The horizontally-mounted crossfader enables the DJ to smoothly transition from a song on one sound source to a song from a different sound source.

      DJ mixers are small audio mixing consoles specialized for DJing. Most DJ mixers have far fewer channels than a mixer used by a record producer or audio engineer; whereas standard live sound mixers in small venues have 12 to 24 channels, and standard recording studio mixers have even more (as many as 72 on large boards), basic DJ mixers may have only two channels. While DJ mixers have many of the same features found on larger mixers (faders, equalization knobs, gain knobs, effects units, etc.), DJ mixers have a feature that is usually only found on DJ mixers: the crossfader. The crossfader is a type of fader that is mounted horizontally. DJs used the crossfader to mix two or more sound sources. The midpoint of the crossfader's travel is a 50/50 mix of the two channels (on a two channel mixer). The far left side of the crossfader provides only the channel A sound source. The far right side provides only the channel B sound source (e.g., record player number 2). Positions in between the two extremes provide different mixes of the two channels. Some DJs use a computer with DJ software and a DJ controller instead of an analog DJ mixer to mix music, although DJ software can be used in conjunction with a hardware DJ mixer.

      Headphones

      DJs generally use higher quality headphones than those designed for music consumers. DJ headphones have other properties useful for DJs, such as designs that acoustically isolate the sounds of the headphones from the outside environment (hard shell headphones), flexible headbands and pivot joints to allow DJs to listen to one side of the headphones, while turning the other headphone away (so they can monitor the mix in the club), and replaceable cables. Replaceable cables enables DJs to buy new cables if a cable becomes frayed, worn, or damaged, or if a cable is accidentally cut.

      Closed-back headphones are highly recommended for DJs to block outside noise as the environment of DJ usually tend to be very noisy. Standard headphones have 3.5mm jack but DJ equipment usually requires ¼ inch jack. Most of specialized DJ Headphones have an adapter to switch between 3.5mm jack and ¼ inch jack. Detachable coiled cables are perfect for DJ Headphones.[27]

      Software

      A screenshot of Mixxx DJ software running on Mac OS X

      DJs have changed their equipment as new technologies are introduced. The earliest DJs in pop music, in 1970s discos, used record turntables, vinyl records and audio consoles. In the 1970s, DJs would have to lug heavy direct drive turntables and crates of records to clubs and shows. In the 1980s, many DJs transitioned to compact cassettes. In the 1990s and 2000s, many DJs switched to using digital audio such as CDs and MP3 files. As technological advances made it practical to store large collections of digital music files on a laptop computer, DJ software was developed so DJs could use a laptop as a source of music instead of transporting CDs or vinyl records to gigs. Unlike most music player software designed for regular consumers, DJ software can play at least two audio files simultaneously, display the waveforms of the files on screen and enable the DJ to listen to either source.

      The waveforms allow the DJ see what is coming next in the music and how the playback of different files is aligned. The software analyzes music files to identify their tempo and where the beats are. The analyzed information can be used by the DJ to help manually beatmatch like with vinyl records or the software can automatically synchronize the beats. Digital signal processing algorithms in software allow DJs to adjust the tempo of recordings independently of their pitch (and musical key, a feature known as "keylock". Some software analyzes the loudness of the music for automatic normalization with ReplayGain and detects the musical key. Additionally, DJ software can store cue points, set loops, and apply effects.

      As tablet computers and smartphones became widespread, DJ software was written to run on these devices in addition to laptops. DJ software requires specialized hardware in addition to a computer to fully take advantage of its features. The consumer grade, regular sound card integrated into most computer motherboards can only output two channels (one stereo pair). However, DJs need to be able to output at least four channels (two stereo pairs, thus Left and Right for input 1 and Left and Right for input 2), either unmixed signals to send to a DJ mixer or a main output plus a headphone output. Additionally, DJ sound cards output higher quality signals than the sound cards built into consumer-grade computer motherboards.

      Timecode

      Special vinyl records (or CDs/digital files played with CDJs) can be used with DJ software to play digital music files with DJ software as if they were pressed onto vinyl, allowing turntablism techniques to be used with digital files. These vinyl records do not have music recordings pressed on to them. Instead, they are pressed with a special signal, referred to as "timecode", to control DJ software. The DJ software interprets changes in the playback speed, direction, and position of the timecode signal and manipulates the digital files it is playing in the same way that the turntable manipulates the timecode record.

      This requires a specialized DJ sound card with at least 4 channels (2 stereo pairs) of inputs and outputs. With this setup, the DJ software typically outputs unmixed signals from the music files to an external hardware DJ mixer. Some DJ mixers have integrated USB sound cards that allow DJ software to connect directly to the mixer without requiring a separate sound card.

      DJ controllers

      A DJ software can be used to mix audio files on the computer instead of a separate hardware mixer. When mixing on a computer, DJs often use a DJ controller device that mimics the layout of two turntables plus a DJ mixer to control the software rather than the computer keyboard & touchpad on a laptop, or the touchscreen on a tablet computer or smartphone. Many DJ controllers have an integrated sound card with 4 output channels (2 stereo pairs) that allows the DJ to use headphones to preview music before playing it on the main output.[28]

      Other equipment