Vinyl emulation software
||This article needs additional citations for verification. (June 2006)|
Vinyl emulation software allows the user to physically manipulate the playback of digital audio files on a computer using the turntables as an interface, thus preserving the hands-on control and feel of DJing with vinyl. This has the added advantage of using turntables to play back audio recordings not available in phonograph form. This method allows DJs to scratch, beatmatch, and perform other turntablism that would be impossible with a conventional keyboard-and-mouse computer interface or less tactile control devices. The technology is also referred to as DVS for either Digital Vinyl System or Digital Vinyl Software.
Vinyl emulation normally uses special vinyl records which are played on conventional turntables. The vinyl is a recording of analogue audio signals often referred to as timecode. The turntables' audio output - the timecode recording - is routed into an analog-to-digital converter, or ADC. This ADC may be a multi-channel soundcard or a dedicated external USB or firewire audio interface box, DJ controller device or compatible mixer (usually distributed with the software). The ADC sends digital time code information to the software, which then translates the signal into corresponding changes in the playback speed, direction and position of a digital audio file. The audio file will react as if were pressed directly onto the record. The manipulated audio output of the program is then sent back through the DAC or the computer's sound card, and can be routed into an audio mixer where it can be mixed like any other analog audio signal.
The result is digital audio playback that sounds like music manipulated by an analogue vinyl recording. However, there is always a short delay between the needle's reading of the time code and the software's playback of the audio. The delay time is treated as a figure of merit for vinyl emulation products. A shorter delay allows the DJ to have better response and control of the music and is usually not noticeable by the user or listener.
Software packages 
Final Scratch was the first vinyl emulation software sold publicly. Since its release in 2001, many similar software and hardware packages have been developed and marketed.
The following applications are licensed under the terms of the GNU General Public License:
Proprietary software applications include:
- Final Scratch
- Traktor Scratch Pro
- Serato Scratch Live
- Numark CUE
- MixVibes DVS
- MS Pinky
- Reflex PCDJ
See also 
- Technical Information and Tips on Torq's Vinyl Control System by Chad Carrier, a technical abstract on Torq Control Vinyl time-code.