Impulse Tracker

Impulse Tracker is a multi-track digital sound tracker (music sequencer). It was one of the last tracker programs for the DOS platform. It was authored by Jeffrey "Pulse" Lim, and example music was provided by Jeffrey Lim and Chris Jarvis. The first released version is from year 1995 and the last version, v2.14 Patch #5, was released April 8, 1999.

History
The software was distributed as freeware, though for a fee the author supplies extra features, such as support for WAV output and co-editing songs over IPX networks. After the stereo WAV writer plugin was publicly pirated, the original author announced that he would discontinue development after version 2.14. Impulse Tracker was coded in Assembly language.

Impulse Tracker 's interface was influenced by that of Scream Tracker 3.

Usage
Like in most module editors, music is arranged on a grid of channels. Each supports note on and note off instructions similar to MIDI. Impulse Tracker modules use the .IT file extension.

New Note Actions (NNAs) is a feature that handles commands received on the same channel as another instrument which is still playing. NNAs allow the user to customize the subsequent action:
 * Cut: The new instrument replaces the current instrument.
 * Continue: The old instrument continues to play using its ADSR curve.
 * Off: The old instrument begins the release section of its ADSR curve.
 * Fade: The old instrument fades out to 0 volume at a designated rate overriding the ADSR curve.

Impulse Tracker supports hardware MIDI channels on the Gravis Ultrasound, InterWave and Sound Blaster 32 card families (provided enough RAM is available).

Compatible software
Other music-playing software that supports the IT file format include Media Player Classic, Winamp (Win32), VLC, Cowon jetAudio, XMMS (X11 Linux/Unix), TiMidity, MikMod, ModPlug Tracker, Renoise (Win32, GNU/Linux and Mac OS X), XMPlay, and Schism Tracker (Win32, Linux, Wii and Mac OS X) which is an Impulse Tracker reimplementation.

IT file format
The .IT file format is the format native to Impulse Tracker. It is similar to older formats such as .MOD, but features new additions such as new note actions which allow the user to customize subsequent actions on receiving commands from the same channel as the one playing.

Some player software supports the .ITZ format, which is a renamed zip file that contains a .IT file.

Impulse Tracker clones
Schism Tracker is intended to match the look and feel of Impulse Tracker as closely as possible. The user interface is built on Simple DirectMedia Layer, which makes it highly portable: Schism Tracker can be run on FreeBSD, Linux, Mac OS X, MorphOS, Windows and ZETA. A modified version of the LibModPlug library is used for player features. Supported formats include IT, S3M, MOD, MT2 and XM. Saving to WAV and MIDI are also supported. It is free software available under the GNU General Public License.

BeRoTracker is a closed source freeware modular tracker which supports the loading and saving of MOD, XM, S3M, IT files and its native format BRT. It supports VST/VSTi and various MIDI-related operations (MIDI in, out, import and export), plus it supports the extensions to legacy formats introduced in ModPlug Tracker. It also comes with an experimental interface which mimics that of Impulse Tracker. BeRoTracker is only available for Windows, however a Linux build is currently in the works.

reViSiT is a Virtual Studio Technology instrument, developed by Chris Nash, which has an interface derived from Impulse Tracker 2. The VST architecture allows the program to run within a host application (examples include AudioMulch, Jeskola Buzz and Psycle) - allowing tracking and sequencing in the same song. The program supports MOD, S3M, XM and IT files, and saves its own songs either automatically in the host's own format, or in a ZIP archive containing module information in XML format and samples in Microsoft WAV format. reViSiT supports both MIDI (e.g. external devices or other VSTi) and sampled instruments. The software is closed source freeware, but a professional version, designed for surround sound with improved audio routing, is planned for the future. Versions supporting non-Windows platforms, such as Unix and Mac, are also planned.

ChibiTracker is an Impulse Tracker clone created by Juan Linietsky also known as Reduz or Reduzio. It was released 24 November 2006. The tracker features custom skins and an advanced sample editor. It is open source and can be compiled on Windows, Mac OS, Linux, FreeBSD and BeOS. ChibiTracker can load and save modules in .MOD (ProTracker Module), .S3M (Scream Tracker 3 Module), .XM (FastTracker II Module) and .IT (Impulse Tracker Module).

CheeseTracker is a GNU General Public License Impulse Tracker clone created by Juan Linietsky also known as Reduz, based on the Qt graphical toolkit. It runs on Mac OS X, Linux and some other Unix-like operating systems. The same person also wrote ChibyTracker, a portable, multi-platform Impulse Tracker clone with several additions such as chorus, reverb, stereo samples, and an advanced sample editor. It is currently available under Windows, Mac OS X, Linux, FreeBSD and BeOS.

Software .IT players

 * Media Player Classic is a freeware open source programme that fully supports this module.
 * Winamp (Win32), a popular MP3 player that supports module formats. (Until today Winamp has never supported .IT files 100% perfectly. For example, retriggered notes and resonant filters are still not played correctly)
 * VLC
 * XMMS, an X11 (Linux/Unix) MP3 and module player modelled on Winamp.
 * TiMidity, a multi-interface MIDI/MOD player
 * MikMod
 * ModPlug Tracker, a tracker with support for VST effect plugins, DLS, SF2 sound banks and Dolby ProLogic Surround
 * Renoise (Win32, GNU/Linux and Mac OS X), music tracker software
 * jetAudio

Users
Erez Aizen of Infected Mushroom composed his first trance music on Impulse Tracker. Ian Stocker used IT with other software in his collaboration for the music in the Nintendo DS version of The Sims 2.

The video games Pocket Tanks and Grid Wars use the IT format for some of their songs. Various games by Epic Games such as the first Unreal and Unreal Tournament as well as Deus Ex used the IT format in an "UMX" container format.

Trance producer Sean Tyas began his music production career using Impulse Tracker.

Sound examples

 * Pale Dreams - included with an early release of Impulse Tracker (.IT module)
 * IndusTree's Homesick (ogg)
 * Gerador Zero - Zero (mp3) (.IT module)
 * Sunset Jazz - Frank Schanzenbächer (Impulse Tracker Original) (RealAudio Version)
 * Quasian - Magenta Magnet (it)
 * Secretly Wishing - Demo song included with Schism Tracker (MP3 version) (.IT module)