A software instrument can be a synthesized version of a real instrument (like the sounds of a violin

Violin

The violin is a string instrument, usually with four strings tuned in perfect fifths. It is the smallest, highest-pitched member of the violin family of string instruments, which includes the viola and cello....

 or drum

Drum

The drum is a member of the percussion group of musical instruments, which is technically classified as the membranophones. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a...

s), or a unique instrument, generated by computer software. Software instruments have been made popular by the convergence of synthesizers and computers, as well as sequencing software like GarageBand

GarageBand

GarageBand is a software application for Mac OS X and iOS that allows users to create music or podcasts. It is developed by Apple Inc. as a part of the iLife software package on Mac OS X.-Audio recording:...

, Logic Pro

Logic Pro

Logic Pro is a hybrid 32 / 64 bit digital audio workstation and MIDI sequencer software application for the Mac OS X platform. Originally created by German software developer Emagic, Logic Pro became an Apple product when Apple bought Emagic in 2002...

 (geared toward professionals), the open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 project Audacity

Audacity

Audacity is a free software, cross-platform digital audio editor and recording application. It is available for Windows, Mac OS X, Linux and BSD.Audacity was created by Dominic Mazzoni while he was a graduate student at Carnegie Mellon University...

, and Ableton Live

Ableton Live

Ableton Live is a loop-based software music sequencer and DAW for Mac OS and Windows by Ableton. The latest major release of Live, Version 8, was released in April 2009. In contrast to many other software sequencers, Live is designed to be an instrument for live performances as well as a tool for...

 which is geared towards live performances. Also of note is software like Csound

Csound

Csound is a computer programming language for dealing with sound, also known as a sound compiler or an audio programming language, or more precisely, a C-based audio DSL. It is called Csound because it is written in C, as opposed to some of its predecessors...

 and Nyquist

Nyquist (programming language)

Nyquist is a programming language for sound synthesis and analysis based on the Lisp programming language. It is an extension of the XLISP dialect of Lisp....

, which can be used to program software instruments.

A software instrument is akin to a soundfont.