Overview

The first to practice the synthesis of musical sounds may have been Organ manufacturers, who by combining several pipes attempted to recreate the human voice (which led to the regal category) or the sounds of orchestra instruments (see section 2.5.1.3). For example, in gamba stops, two pipes play together slightly out of tune in order to produce a beat, simulating the undulation of string instruments: this is called the voix c leste, a typical organ stop of the romantic narrative. The 20 ^th century saw the coming of electronic synthesis instruments (organs, various keyboards), combining, among other things, oscillating circuits and filters to produce musical sounds. Composers such as Pierre Henry took advantage of the new possibilities offered by these electro-acoustic sounds. Today, a remarkable advantage provided by digital technology is the possibility to create all kinds of sounds with a computer, from the imitation of acoustic or electronic instruments to the creation of entirely synthetic sounds, such as the Modalys synthesis system developed by the IRCAM (the French Acoustics and Music Research and Coordination Institute) [PRO 95]. We are going to see a few simple processes to create such sounds.

Even though it is difficult to precisely define what makes them different from an actual sound, we can say that sound effects are modifications of pre-existing sounds. They have probably always been used, and acoustic instruments provide a few examples: pedals on harpsichords and pianos, different types of mutes for the trumpet, but also...