Tone.js is a Web Audio framework for creating interactive music in the browser. The architecture of Tone.js aims to be familiar to both musicians and audio programmers looking to create web-based audio applications. On the high-level, Tone offers common DAW (digital audio workstation) features like a global transport for scheduling and timing events and prebuilt synths and effects. For signal-processing programmers (coming from languages like Max/MSP), Tone provides a wealth of high performance, low latency building blocks and DSP modules to build your own synthesizers, effects, and complex control signals.
A unique feature of the library is the Transport which allows for application-wide synchronization of sources and signals with tempo curves and automation. The Transport allows you to register callbacks at precise moments along the timeline which are invoked right before the event with the exact time of the event.
In the Tone library, time can be described in a number of ways. Any method which takes a time as a parameter will accept the number in seconds as well as a tempo-relative form.
Aside from the 4 basic oscillator types (sine, square, triangle, sawtooth), Tone.js provides a few other sources such as a buffer player (Tone.Player), a noise generator, and two additional oscillator types (pwm, pulse).
Tone has a number of instruments which all inherit from Tone.Instrument, giving them the same API for triggering notes. These instruments are all monophonic and can be made polyphonic if they are passed into the second argument of [Tone.PolySynth](http://tonejs.org/docs/#PolySynth).
Like the underlying Web Audio API, Tone.js is built with audio-rate signal control over nearly everything. This is a powerful feature which allows for sample-accurate synchronization of multiple parameters with a single signal. Signals are built entirely without the ScriptProcessorNode so they do not introduce much latency and processing overhead. Instead, all signal math and logic let GainNodes and WaveShaperNodes do all of the work so that all processing is done in the underlying Assembly/C/C++ provided by the API. Signals are used extensively internally and are also useful for general DSP and control signal logic and transformations.
Tone.js creates an AudioContext when it loads and shims it for maximum browser compatibility. The AudioContext can be found at `Tone.context` or from within any Object extending Tone as `this.context`.
To use MIDI files, you'll first need to convert them into a JSON format which Tone.js can understand using [MidiConvert](tonejs.github.io/MidiConvert/).
Tone.js uses very few ScriptProcessorNodes. Nearly all of the Tone Modules find a native Web Audio component workaround, making extensive use of the GainNode and WaveShaperNode especially, which enables Tone.js to work well on both desktop and mobile browsers. While the ScriptProcessorNode is extremely powerful, it introduces a lot of latency and the potential for glitches more than any other node.
