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Beatmatching or pitch cue is a disc jockey technique of pitch shifting or timestretching an upcoming track to match its tempo to that of the currently playing track, and to adjust them such that the beats (and, usually, the bars) are synchronised -- i.e., the kicks and snares in two house records hit at the same time when both records are played simultaneously. Beatmatching is a component of beatmixing which employs beatmatching combined with equalization, attention to phrasing and track selection in an attempt to make a single mix that flows together and has a good structure.
The technique was developed to keep the people from leaving the dancefloor at the end of the song. These days it is considered basic among disc jockeys (DJs) in electronic dance music genres, and it is standard practice in clubs to keep the constant beat through the night, even if DJs change in the middle.
Beatmatching is no longer considered a novelty, and new digital software has made the technique much easier to master.
The beatmatching technique consists of the following steps:
One of the key things to consider when beatmatching is the tempo of both songs, and the musical theory behind the songs. Attempting to beatmatch songs with completely different beats per minute (BPM) will result in one of the songs sounding too fast or too slow.
When beatmatching, a popular technique is to vary the equalization of both tracks. For example, when the kicks are occurring on the same beat, a more seamless transition can occur if the lower frequencies are taken out of one of the songs, and the lower frequencies of the other song is boosted. Doing so creates a smoother transition.
The pitch and tempo of a track are normally linked together: spin a disc 5% faster and both pitch and tempo will be 5% higher. However, some modern DJ software can change pitch and tempo independently using time-stretching and pitch-shifting, allowing harmonic mixing. There is also a feature in most modern DJ software to change the tempo but keeping the original pitch, this is often referred to as master tempo or key adjust.
Beatmatching was invented by Francis Grasso in the late 1960s and early 1970s. Initially he was counting the tempo with a metronome and looking for records with the same tempo. Later a mixer was built for him by Alex Rosner which let him listen to any channel in the headphones independently of what was playing on the speakers; this became the defining feature of DJ mixers. That and turntables with pitch control enabled him to mix tracks with different tempo by changing the pitch of the cued (redirected to headphones) track to match its tempo with the track being played by ear. Essentially, the technique he originated hasn't changed since.
These days[when?] beat-matching is considered central to DJing, and features making it possible are a requirement for DJ-oriented players. In 1978, the Technics SL-1200MK2 turntable was released, whose comfortable and precise sliding pitch control and high torque direct drive motor made beat-matching easier and it became the standard among DJs. With the advent of the compact disc, DJ-oriented Compact Disc players with pitch control and other features enabling beat-matching (and sometimes scratching), dubbed CDJs, were introduced by various companies. More recently, software with similar capabilities has been developed to allow manipulation of digital audio files stored on computers using turntables with special vinyl records (e.g. Final Scratch, M-Audio Torq, Serato Scratch Live) or computer interface (e.g. Traktor DJ Studio, Mixxx, Virtual DJ). Other software including algorithmic beat-matching is Ableton Live, which allows for realtime music manipulation and deconstruction, or Mixmeister, a DJ Mixset creation tool. Freeware software such as Rapid Evolution can detect the beats per minute and determine the percent BPM difference between songs.
The change from pure hardware to software is on the rise, and big DJs are introducing new equipment to their kits such as the laptop, and dropping the difficulty of carrying hundreds of CDs with them. The creation of the mp3-player allowed DJs to have an alternative tool for DJIng. Limitations with mp3-player DJing equipment has meant that only second generation equipment such as the IDJ2 or the Cortex Dmix-300 have the pitch control that alters tempo and allows for beat-matching on a digital music player. However, recent additions to the Pioneer CDJ family, such as the CDJ-2000, allow mp3-player and other digital storage devices (such as external hard drives, SD cards and USB memory sticks) to be connected to the CDJ device via USB. This allows the DJ to make use of the beat-matching capabilities of the CDJ unit whilst playing digital music files from the mp3-player or other storage device.
Most modern DJ hardware and software now offers a "Sync" feature which automatically adjusts the tempo between tracks being mixed so the DJ no longer needs to spend time and effort matching beats. This has caused some controversy in the DJ industry since almost anyone can beat-match thanks to the new function.