Final Scratch
Encyclopedia
Final Scratch is a DJ tool created by the Dutch company N2IT with input from Richie Hawtin
Richie Hawtin
Richard Hawtin is an English-Canadian electronic musician and DJ who was an influential part of Detroit techno's second wave of artists in the early 1990s and a leading exponent of Minimal techno since the mid 1990s...

 (aka Plastikman) and John Acquaviva
John Acquaviva
John Acquaviva is an Italian-born Canadian second-wave techno artist and club DJ from London, Ontario. His friend Richie Hawtin co-founded the Plus 8 record label with him in 1990.In 2006, Acquaviva reached #22 on the ....

 that allows manipulation and playback of digital audio
Digital audio
Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...

 sources using traditional vinyl and turntables. It seeks to cross the divide between the versatility of digital audio and the tactile control of vinyl turntablism
Turntablism
Turntablism is the art of manipulating sounds and creating music using phonograph turntables and a DJ mixer.The word 'turntablist' was coined in 1995 by DJ Babu to describe the difference between a DJ who just plays records, and one who performs by touching and moving the records, stylus and mixer...

.

Concept

Special vinyl records pressed with a digital timecode are played on normal turntables. The timecode signal is interpreted by a computer, connected to the turntables through an interface called the ScratchAmp. The signal represents where the stylus is on the record, in which direction it is traveling, and at what speed. This information is interpreted by the computer and used to play back a digital audio file which has been 'mapped' to the turntable. In practical terms, this means that any audio file can be manipulated as though it were pressed on vinyl.

Advantages/Disadvantages

Advantages:
  • Ability to play audio tracks unavailable on vinyl e.g. pre-arranged loops
    Music loop
    In electroacoustic music, a loop is a repeating section of sound material. Short sections of material can be repeated to create ostinato patterns...

    , unreleased music or rare tracks
  • The use of CD deck features (software permitting) such as keylock, pitch shift
    Pitch shift
    Pitch shifting is a sound recording technique in which the original pitch of a sound is raised or lowered. Effects units that raise or lower pitch by a pre-designated musical interval are called "pitch shifters" or "pitch benders".-Pitch/time shifting:...

    , looping
    Music loop
    In electroacoustic music, a loop is a repeating section of sound material. Short sections of material can be repeated to create ostinato patterns...

    , instant cue locating and visual indicators of audio features such as loud or quiet parts
  • The ability to prevent needle skips on the vinyl being reflected in the playback of the audio track being played/controlled (software permitting)


Disadvantages:
  • Reliability; depending on the hardware/software configuration used, vinyl emulation systems may use more system resources than some laptops or PCs
    Personal computer
    A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

     offer, making them unsuitable for this use.

History

The original Final Scratch concept and prototypes were developed by the Dutch company N2IT V.O.F, by Mark-Jan Bastian, with help from Tim Hemel and Bill Squire.
It has passed through multiple stages of development. These stages are marked by involvement with different companies, hardware configurations, software developers, licensees and licensors, and operating systems.

Versions 1.0-1.5

All versions of Final Scratch 1 use the same Scratchamp, a USB
Universal Serial Bus
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....

 and RCA device in a round plastic shell. The technical specifications of this device have been closely guarded by Stanton as an anti-piracy measure, though some users, unsatisfied with the latency and instability of the system, have alleged the use of faulty Philips sound chips which had already been withdrawn from the market. However, the same chipset was being used in several other USB audio devices manufactured by companies like Griffin and Roland at that time.

FS 1.0 was released for PC only, on a specially modified distribution of Debian
Debian
Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...

 Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

. It was relatively primitive but some users found that, if configured correctly, it outperformed all subsequent versions of Final Scratch 1.x.

With version 1.1, Stanton Magnetics
Stanton Magnetics
Stanton Magnetics, founded in 1946, is a manufacturer of professional and consumer audio equipment. Most of its products are aimed at DJs. It is a wholly owned subsidiary company of the privately owned Stanton Group who also own Cerwin-Vega and KRK Systems...

 began working with Native Instruments
Native Instruments
Native Instruments is a technology company that develops software and hardware for music production and DJing. The company has originally been identified mostly with software instruments, but has also expanded to various other music equipment segments in recent years.Current products of Native...

 on the software side of the product, which became Traktor Final Scratch. As the name suggests, this bore a resemblance to the interface of Traktor, a Native Instruments software DJing product. This version was once again available on Linux, but was also ported to Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

.

The next major revision was version 1.5, which added a Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...

 version, but dropped Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 support. This version also added the ability to keep the pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

 of the record constant whilst shifting the tempo
Tempo
In musical terminology, tempo is the speed or pace of a given piece. Tempo is a crucial element of any musical composition, as it can affect the mood and difficulty of a piece.-Measuring tempo:...

. The interface changed very little, but some users initially had issues with the Windows Scratchamp drivers.

Support for the original Scratchamp has all but since disappeared and current owners, disappointed by the lack of support by Stanton, have had to rely on old versions of Traktor FS or Digiscratch.

Version 2

Version 2 marks the introduction of both a new Scratchamp hardware device and different software compatibility.

This new Scratchamp made 24-bit/96 kHz digital quality playback and record possible. Stanton added an ASIO
Audio stream input output
Audio Stream Input/Output is a computer sound card driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer's sound card...

 driver, and MIDI capabilities. They also replaced the USB
Universal Serial Bus
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....

 interface with Firewire which was intended to reduce playback latency. The new Scratchamp was developed by Alan Flum, Len Bryan, Mark DeMouy and Jim Mazur.

The version 2 Scratchamp is compatible with Native Instruments
Native Instruments
Native Instruments is a technology company that develops software and hardware for music production and DJing. The company has originally been identified mostly with software instruments, but has also expanded to various other music equipment segments in recent years.Current products of Native...

 Traktor DJ Studio versions 2.6 and through 3.2.0.85 (Mac). NI has dropped support of SA2 in favor of their own vinyl system Traktor Scratch.

Final Scratch Open

In late 2005, Stanton and Native Instruments ended their working relationship. Stanton still markets the ScratchAmp hardware as part of Final Scratch Open, introduced in early 2007. Stanton claims that the ScratchAmp can now interact with any audio software through ASIO
Audio stream input output
Audio Stream Input/Output is a computer sound card driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer's sound card...

 or WDM
Windows Driver Model
In computing, the Windows Driver Model — also known at one point as the Win32 Driver Model — is a framework for device drivers that was introduced with Windows 98 and Windows 2000 to replace VxD, which was used on older versions of Windows such as Windows 95 and Windows 3.1, as well...

 on Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

, and CoreAudio in Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

. Although all Windows and Mac audio software is ostensibly compatible with Final Scratch Open, there is no dedicated software program for deejaying with the ScratchAmp hardware.

Internal workings

The internal workings of Final Scratch are quite simple to understand. Multiple open source software libraries have been created to decode the Final Scratch time code. The information here comes from those libraries.

A basic Final Scratch setup consists of five pieces of equipment.
  1. A computer running a compatible software, usually Native Instrument's Traktor
  2. The ScratchAmp
  3. Two turntables or two CD decks made for DJing
  4. Two time coded vinyl records or time coded CDs
  5. An audio DJ mixer.

ScratchAmp

The ScratchAmp is a firewire (FS 2, FS Open) or USB (FS 1) audio device. It has two phono/line stereo level inputs to read the timecode from the record or the CD, and two line level stereo outputs to feed into the audio DJ mixer line channels. It also has two phono stereo outputs for pass-through of the actual phono audio signal. This is useful for DJs who wish to play both digital audio tracks AND traditional vinyl; allowing them to switch between the two sources without disconnecting or re-connecting audio jacks in the middle of a DJ set.

The ScratchAmp does not store any audio on its own, it is simply a purpose built external Soundcard. It communicates with a PC—usually a laptop—over the firewire or USB connection. The laptop uses Final Scratch compatible software (typically Traktor DJ Studio) to interpret the timecode signal from the supplied special vinyl/CD, then play back a digital audio file based on that signal, allowing traditional DJ vinyl control of MP3, WAV and Apple AAC audio files. The Laptop software then sends audio data back, over the same firewire/USB connection to the scratch amp, which then sends an audio signal out through the line level output, for playing through a DJ Mixer or Amp.

Audio/data routing

A step by step series of events detailing how Final Scratch operates;
  1. Timecoded audio signal pressed onto vinyl/CD picked up by vinyl/CD turntable
  2. Signal routed into ScratchAmp via phono connection, then into the PC via USB or Firewire
  3. DJ software decodes timecode signal and determines position, speed and direction the Vinyl/CD is being played or manipulated
  4. DJ software plays the selected "mapped" digital audio file synchronous to the vinyl/CD playback
  5. Digital audio file audio signal is sent to the Scratchamp phono connectors for connection to a DJ mixer or amp

Vinyl/CD time code

The most complex piece of the Final Scratch setup is the code pressed onto the vinyl. A 1200 hertz amplitude modulated sine wave is pressed into the left and right channels with a phase difference of 90 degrees. Each channel holds one of the two bit streams required for the time code. In one cycle of either wave form, two bits are stored: one on the positive voltage peak and one on the negative voltage valley. The relative amplitudes of these peaks represent either a binary one or zero. A relatively high amplitude on either peak represents a one, a relatively low amplitude represents a zero. In each channel is a separate bitstream, the left channel is not identical to the right (disregarding the phase difference).

Finding position

The time codes themselves consist of 40 individual bits, or 20 cycles on each channel's waveform. On the right channel the bit sequence of 0, 0, 0, 1 represents the start sequence for a single time code. Those four bits along with the four corresponding bits on the left channel and the next 16 bits on each channel can be decoded as an integer position value which represents where the needle is on the record.

Finding speed

The speed at which the record is spinning can be found by comparing the frequency of the waveform being read from the record to the true frequency of the wave form on the record at normal speed. This difference represents the change from the normal speed at which the record turns.

Finding direction

The direction which the record is spinning at any given time can be found using the phase difference between the waves on the two channels. This procedure is the same as that used to determine the direction in which a ball mouse is moving.

Issues regarding time code errors

Because a single time code is made up of 40 consecutive bits, read errors can cause a timecode to be unreadable even if a single bit is misread. A bit that has become unreadable due to a scratch can make an entire 40 bit long time code permanently unreadable. Dust can have a similar effect on the time code. The time code implements very little error checking, an attribute strong in a number of other vinyl control systems.

Other vinyl emulation systems

  • Serato Scratch Live
  • djDecks
  • PCDJ Scratch
  • Ms Pinky
  • D-Vinyl 20-20
  • Traktor Scratch
  • Mixxx
    Mixxx
    Mixxx is open source digital DJ'ing software that allows an individual to mix music using a personal computer, as a DJ would with a pair of physical turntables. It is specifically suited to the style of mixing known as beatmatching. - Overview :...

  • xwax
    Xwax
    xwax is open source vinyl emulation software. It was initially developed in 2006 as proprietary software. In May 2007 xwax was licensed under the GNU General Public License, making it the first open source software of this kind....

  • Deckadance
    Deckadance
    Deckadance is a DJ console and mixing tool developed by Image-Line software. Initially released in May of 2007, it operates on Windows and Mac OS X, and comes in a House Edition and Club Edition...

  • Quad Scratch
  • Mixvibes

External links


Sources

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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