# Introduction

When you program with the Audio folio, you work with instruments. Portfolio instruments play notes-sound events that range from a traditional musical note with pitch and duration, to a sound effect such as an explosion, to a straightforward playback of a sampled sound file. Portfolio instruments also work on other instruments, mixing them together, adding special effects such as filtering and reverberation, and controlling their playback. However, before you can hear anything from these instruments, you must first prepare the instruments for playback.

The model for handling Portfolio instruments is the modular analog synthesizer. You can add instruments (the equivalent of synthesizer modules) to the mix, connect instruments together for combined effects (the equivalent of connecting modules), you can tweak each instrument's controls to change playback characteristics over time, and you can trigger each instrument to start, release, and stop notes. The Audio folio's job is to control the full synthesizer, setting up music and sound effects.