Lesson 9 - Virtual Instruments and Synthesis

Objective: In previous lessons, much of what you had learned was hardware based music technology.  We will now take a look at how software "virtual instruments" are revolutionizing the way we experience, compose, perform and listen to music.  In addition, you will learn the basic concepts, terminology and applications of synthesis (creating sounds) and its relationship to virtual instruments and music software.

Example of a Composition Created Entirely From Virtual Instruments

What Are Virtual Instruments?

A virtual instrument is essentially a software version of a real instrument or hardware synthesizer.

A virtual instrument uses your computer to generate the actual sounds. 

These programs are far more affordable than the equivalent of it’s hardware contemporary. (Ex. The physical keyboard/synthesizer itself).  It’s like getting a new keyboard or sound module without having to pay for the physical unit.


A Plug-in is basically a program that runs inside a larger, more complex application/program.

They provide interesting and fun tasks that the “host” program (such as your sequencing program) doesn’t provide.

They are determined by your host program’s Application Programming Interface (API), which allows a compatible plug-in to function within the host music software program.

Most Common Plug-in formats:

AU (Audio Units for Apple OS X Core Audio)

VST (Virtual Studio Technology, with both Mac OS and Windows versions)

MAS (MOTU Audio System, found exclusively in MOTU’s Digital Performer)

DirectX (Microsoft’s multimedia plug-in engine for Windows)

TDM (Time Division Multiplexing for Pro Tools hardware DSP systems)

Audio Suite (a non-real-time format exclusive to Pro Tools)

RTAS (Real Time Audio Suite for native Pro Tools systems)


ReWire is an inter-application communication engine developed by Propellerhead Software (creators of Reason Music Production Software and others).

Allows for MIDI and audio transfer between two software applications in real time.

Example:  When in "Rewire" mode the audio output of an application such as a software synthesizer (soft synth) may be routed to another application such as a DAW (Digital Audio Workstation) mixer, and output with the second application's (mixer’s) audio.

Programs may communicate with each other via MIDI so that one can control the other or so they can be synchronized.

ReWire currently works with many DAW applications including Pro Tools, Digital Performer, Logic, SONAR, Live, ACID, and Cubase. Other applications include GigaStudio, Reason, Project5, and many more.


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