CDJ

A CDJ is a specialized digital music player for DJing. Originally designed to play music from compact discs, many CDJs can play digital music files stored on USB flash drives or SD cards. In typical use, at least two CDJs are plugged into a DJ mixer. CDJs have jog wheels and pitch faders that allow manipulation of the digital music file similar to a vinyl record on a DJ turntable. Many have additional features such as loops and beat analysis that are not present on turntables. Additionally, some can function as DJ controllers to control the playback of digital files in DJ software running on a laptop instead of playing the files on the CDJ.
Many pro audio companies such as Gemini Sound Products, Denon, Numark Industries, Stanton Magnetics, and Vestax produced DJ quality CD players. In 1993 Denon was the first to implement a 2 piece rack mounted dual-deck, variable-pitch, CD player with a jog wheel and instant cue button for DJs. It quickly became the industry standard and was widely adopted in most clubs and mobile DJs throughout the 90s up until 2004 when Pioneer made an impact with the CDJ-1000. Currently, Pioneer DJ CD players are now the most commonly found in dance clubs and are seen as the industry standard by many DJs.
Pioneer CDJs.
The Pioneer CDJ-400, CDJ-800, CDJ850K, CDJ-1000, CDJ-900, CDJ-2000 and the latest model CDJ-3000 have a vinyl emulation mode that allows the operator to manipulate music on a CD as if it were on a turntable. Models released prior to the CDJ-1000 lack this feature. Pioneer CDJs released after the CDJ-400 can play from USB sticks as well as CDs. Pioneer integrates its software rekordbox with the CDJs to prepare music with cue points, accurate BPM, and search/playlist functions. For unknown reasons, the Pioneer CDJ-300 is left out of most popular accounts on CDJs. Archive of the product description for the CDJ 300 www.cddj.com/ppdj/products/cdj300/cdj300.php 
The CDJ-100S is a CDJ model that was released in early 1998. The CDJ-100S is a basic CD player with a pitch controller and three sound effect options.
The CDJ-200 is the discontinued budget model CDJ CD player released in 2004. It is similar in size to the CDJ-100S, however features such as MP3 playback capabilities and loop functions have been added or improved. Both the CDJ-100S and the CDJ-200 have similar options to manipulate the CD, however they lack the vinyl modes of other models.
The CDJ-400 was released in the late 2007. It is similar in size to the CDJ-200, but comes with scratching abilities and effects, as well as being Pioneer's first model to have a USB input. This makes it possible to play MP3 music from a USB memory stick.
On the back of the CDJ-400 is another USB connector that can be used to connect the CDJ-400 to a computer. This will enable the MIDI control possibilities so the player can be used to control various types of DJ mix software. The CDJ-400 has a built in USB sound card.
The CDJ-500 (known as the "Mark 1" once the second version was released) was the first* CDJ CD player released by Pioneer. (The CDJ-500 is recognized as the first; however, there is a Pioneer CDJ-300 that was released in 1992). http://adamch.com/history-of-the-pioneer-cdj/
The first Pioneer player to have a Jog Dial, (although Technics were the first to feature a jog dial in 1986 with the SL-P1200), allowing for cueing of the CD unlike rack-mounted CD players that were common at the time. It included a loop function, as well as loop-out adjust, and other facilities associated with looping samples from the track being played. The pitch control was +/- 10% only, and Master Tempo allowed the pitch to be locked despite tempo changes being made.
All models of the 500 had top-opening CD loading, which is opposite to all the later ranges of CDJs (starting with CDJ-100S in 1999) which have since had front slot-loading of discs.
Pioneer later released the CDJ-500II, with the only changes being slightly faster performance, Loop Out adjustable and the maximum loop length was increased to 10 minutes.
The CDJ-500S (also known as the CDJ-700S in the United States) was a smaller version of the CDJ-500. It marked the first inclusion of an anti-skip system.
The CDJ-800 uses a different mechanism for the jog wheel than the 1000 - it can perform "quick return" if the top surface of the wheel is pressed, then released. The general design purpose of the CDJ-800 was to offer DJs the facilities they have in the club on CDJ-1000s at home for a lower price. While the CDJ-1000 has a button to override the pitch slider, the CDJ-800 slider has a center detent, which is "easy to center." The CDJ-800 does not have the CDJ-1000's "hot cue" feature, and has only "one cue, and one loop" at a time, though these can be saved for up to 500 CDs. The CDJ-800 can alter loop "out-points" while playing, but can't alter in-points; loops must be re-captured. Though the CDJ-1000 will relay (alternate CDs) in both vinyl and CDJ jog modes, the CDJ-800 will only relay in CDJ jog mode. The CDJ-800 also has an "auto-beat" function that the 1000 does not.
The CDJ-800 was introduced in November 2002 and discontinued in February 2006 in favor of the updated second-generation version, called CDJ-800-MK2. The main difference is that the CDJ-800-MK2 can play MP3 files from CDs.
The design has also been changed.
Dan Morrell, ("DJ Smurf") wrote of liking the CDJ-800 due its excellent sound and low price.
CDJ-850.
Replacing the CDJ-800MK2, the CDJ-850 offers some major enhancements over its predecessor. This deck is designed to feel and function like a CDJ-900 or CDJ-2000 and is rekordbox enabled, while maintaining an affordable price. As compared to the CDJ-900's tracking accuracy of 1ms, however, the CDJ-850 has accuracy of only 1 frame (13ms), which can make seamless looping impossible without constant adjustments. Also the CDJ-850 has USB functionality with rekordbox capability.
CDJ-900.
The Pioneer CDJ-900 was announced simultaneously with Pioneer CDJ-2000 on September 17, 2009. The player has been available since the end of December 2009.
The CDJ900 was placed below the Pioneer CDJ-2000, but above the Pioneer CDJ-850 and the Pioneer CDJ-350. It includes features on the Pioneer CDJ-2000 including a tilted screen, Pro DJ Link, and Serato HID support. Features that set it apart from the Pioneer CDJ-850 include a larger screen with dedicated playback and browse screens, Quantize, and .5 frame step.
A unique feature was the inclusion of "slip" mode. This was not included on the Pioneer CDJ-2000, Pioneer CDJ-850, or the Pioneer CDJ-350. This allowed you to manipulate the track and for it to return to where it should have been if you had not manipulated the track. If you enable a loop at 02sec, leave it for 1min, then disengage the loop, it will jump to 1:02 as if you had never engaged the loop.
This CDJ allows playback from USB drives, Audio CD, MP3 CD, act as a MIDI controller, and is an Official Serato Accessory for HID Playback. HID playback allows you to use all the CDJ-900 as a controller for the computer program Serato, but at a much higher resolution than MIDI, and have access to all the features of the CDJ-900.
CDJ-1000.
The CDJ-1000 (retroactively known as the mk1 after the release of mk2) was a digital turntable by Pioneer Electronics in 2001 that was used to play CDs and was generally accepted as the first CD player that can accurately emulate a vinyl turntable - including the ability to scratch - and became a popular CD player used by DJs.
The player implements a large touch-sensitive platter with a digital display in the middle that can relay information about the position in the music. Although this platter is not driven (meaning that it does not rotate by itself) like a turntable, the display in the center shows positioning information for accurate cueing. Also there is an orange Cue marker that simulates the stickers used by scratch DJs. The waveform display gives DJs the opportunity to look ahead on tracks to see forthcoming breaks.
The CDJ-1000 (and its reincarnations) has become a popular tool for dance clubs and DJs, and is currently the most widely used DJ-style CD deck to be found in the booths of world's best nightclubs. The player supports playback from CD, CD-R and CD-RW and implements all of the essential features for DJ CD players such as looping and pitch changing in addition to less common features such as reverse play-back and turntable break-stop and start. It includes the master tempo-function introduced on the earlier CDJ-500 & CDJ-500S models, whereby the music changes speed while maintaining pitch.
It is generally thought to be the first CD player to be widely adopted in club use. Until this point few clubs bothered with CD machines in them, either due to their lack of DJ functionality and overall robustness, or due to the fact that DJs still liked to use the vinyl format as most of the upfront music they required to play was still much more prevalent on vinyl over CD media. 
The other reason this machine took off in popularity was the release of recordable CD-R and then CD-RW media discs and stand-alone machines which could record music onto them. Before this, DJs who wanted to test in either a club or as early promotional items to radio DJs, a new piece of music they might have made themselves in a studio, often had to rely on getting acetate discs pressed up. These were both expensive to do and had inherent short lifespan; as after a few plays the disc would wear-out and thus be completely unplayable.
Updated versions.
CDJ-1000MK2.
An updated version of the CDJ-1000, the CDJ-1000 MK2 was released on July 2003 with additional features like improved jog wheel and faster response time than in the original model. The product was discontinued in 2006 when the mk3 was introduced into the market.
CDJ-1000MK3.
The third model known as the CDJ-1000 MK3 released in March 2006.
Unlike the earlier versions the mk3 supports playback of MP3s from CD-R and CD-RW media. Other improvements to earlier versions include bigger, lighter displays; a 100 dots waveform display instead of the earlier 50 dots waveform; the ability to record loops into Hot Cue slots instead of just cue points. The mechanical resistance of the jog wheel is adjustable to suit different styles of handling by the DJ. Furthermore, the mk3 uses a newer SD media while the earlier incarnations used MultiMediaCard/MMC as a memory card format.
Discontinuation.
Shortly after the introduction of the CDJ-1000's successors, the Pioneer CDJ-900 and the Pioneer CDJ-2000, in a statement, UK sales manager Martin Dockree said:
CDJ-2000.
The Pioneer CDJ-2000 is the latest addition to the CDJ-range of digital turntables targeted for professional DJs announced simultaneously with the CDJ-900 on September 17, 2009. It became available late December 2009.
The Pioneer CDJ-2000 is the replacement for the now discontinued Pioneer CDJ-1000 MK3.
The Pioneer CDJ-2000 was discontinued to the end of 2012 and was replaced with the Pioneer CDJ-2000 Nexus Released in September 2012. New features include a high resolution screen which displays detailed wave form information as well as Beat-Sync which allows you to automatically beat-match tracks from 2, 3 or 4 players via ProDJLink. The Pioneer CDJ-2000 Nexus is also the first CDJ to allow playback of music stored on a smartphone or tablet via Wi-Fi/USB connection.
The Pioneer CDJ-2000 Nexus was discontinued at the beginning of 2016, and was replaced by the CDJ-2000NXS2, released in February 2016.
CDJ-2000NXS2.
In early 2016, Pioneer unveiled the newest model of its flagship CDJ range: the CDJ-2000NXS2. Containing a high definition full touch screen, eight hot cues, as well as several other features, the CDJ-2000NXS2 was met with much success and praise.
CMX-3000.
The CMX-3000 was Pioneer's second attempt to enter the market of rack-mountable dual deck CD-players. Released in the wake of the CDJ-1000, the player was - and still is - often mistakenly advertised as a "19" inch rack mountable equivalent of dual CDJ-1000s" even though the intended target audiences for the products, as well as their comparative pricing, were entirely in different leagues. The misconception is possibly caused by the fact that while Pioneer's earlier dual deck CD-player, the CMX-5000, only had a jog wheel comparable to earlier single deck CD-players for doing pitch bending, the CMX-3000 also allowed distinct jog mode that enabled the user to use the jog wheel for scratching, a feature that thus far was only available on the top-of-the line CDJ-1000. The jog wheel however relies upon the movement of the wheel itself and is not touch sensitive as it is on the CDJ-1000, CDJ-800 and CDJ-400. Therefore, the scratch is intended as an effect or for cueing a track, and is not appropriate for stopping the track by touch as it is on the other CDJ models.
Mainly due to the product's comparative pricing (for the price of two CDJ-1000s you could get almost three CMX-3000 units with two players each) the CMX-3000s have found their way to the setups of many mobile DJ as well as into the booths of many world's best nightclubs as a backup player in case the industry standard CDJ-1000s fail for some reason during a night.
CMX-5000.
The CMX-5000, released in March 2000, was Pioneer's first attempt to enter the 19" rack mountable dual CD player-market (though, with an optional installation bracket, it had previously been possible to install two CDJ-500S-players side by side into an industry standard rack) that had previously been dominated by Denon.
The CMX-5000 consists of a 2U section with a pair of slot-loading CD drives and a 3U 'controller' section with a pair of jog wheels and control buttons for the CD drive below.
MEP-7000.
The MEP-7000 is Pioneer's addition to their product range for professional DJs released in late 2007. At The 2008 NAMM Show The MEP-7000 was featured along with Pioneer's DJM-3000 19" rackmount DJ mixer. In Australia, the DJM-3000 had been discontinued for sale in late 2006 but was re-released in June 2008 just for the MEP-7000. The player is a 19" rack mountable twin player type capable of playing media formats ranging from normal audio CD/CD-R/CD-RW to digital data files in MP3- and AAC-formats written on DVD's as well as USB-connected memorysticks and/or portable hard drives.
DMP-555.
The DMP-555 was a single deck tabletop CD-player in Pioneer's range for DJs that was introduced in April 2002 and discontinued during 2004. The DMP-555 featured several innovative features, such as playback from SD card, and MP3 playback from either memory card or optical media. It also included the ability (unique in Pioneer's DJ product line) to cue from one media source and playback from another all on the same unit, allowing one to DJ two tracks from a single DMP-555 alone. The product was hobbled by a lack of support and updates, a 2GB limit on SD card capacity, and the inability to write MP3 files directly to the SD card. A special Pioneer-branded writer was required, and transfers had to be encrypted through custom Pioneer software because of music label concerns over copyright infringement.
DVJ-X1.
The DVJ-X1 is a DVD quasi-turntable that allows VJ's to scratch and mix video like a vinyl record. Released in 2004 and designed for professional use in clubs, it features real-time digital video scratching, looping and instant hot cueing. It has capability to sync video and audio streams even when being pitched or reversed. It also plays CDs with features similar to the regular CDJ-1000 CD turntable.
In 2006, Pioneer introduced a successor unit, the DVJ-1000.
DVJ-1000.
The DVJ-1000 is a digital turntable that is capable of playing back video data on DVDs, as well as CD-Audio, and MP3 audio on both CDs and DVDs. Created by Pioneer Electronics in 2006, it is the successor to the Pioneer DVJ-X1.
Unlike the DVJ-X1, the DVJ-1000 is approximately the same dimensions as Pioneer's audio-only CD turntables (CDJ-1000), and can be fitted into existing enclosures with relative ease, allowing for an easy upgrade path for club owners and sound engineers.
In addition, the unit borrows several usability features from the current CDJ line, including a brighter fluorescent display on both the information screen and the central On-Jog display. Loop adjustment features are carried over as well, and a new automatic 4-beat loop feature has been included on this unit.
Being that the unit plays back DVD material, several new outputs have been added, including S/PDIF, composite outputs, a preview video output, which also doubles as a 'dashboard' for searching through video and MP3 content, as well as control outputs for compatible Pioneer DJ mixers.
For the travelling DJ, the unit is multi-system, outputting both PAL and NTSC video signals for near-global compatibility.
As part of its marketing strategy, Pioneer has equipped several noted DJs with the new unit, including Sander Kleinenberg.
Currently, the unit retails for $2500 USD, £1599 GBP, which is about 25 percent less than the introductory pricing on the DVJ-X1.