Beep.js 介绍
Beep.js 是一款使用 WebAudio API 基于浏览器的 JavaScript 工具包，用来开发声音合成应用。你可以使用它来做一个电子琴。
示例：
var trigger = new BEEP.Trigger( '2Eb', function(){
// Let’s call this our “Foundation Voice”
// because it will sing the intended Note.
this.voices.push(
new BEEP.Voice( this.note, this.audioContext )
.setoscillatorType( 'sine' )
.setGainHigh( 0.4 )
)
// This Voice will sing a Perfect 5th above the Foundation Voice.
this.voices.push(
new BEEP.Voice( this.note.hertz * 3 / 2, this.audioContext )
.setoscillatorType( 'triangle' )
.setGainHigh( 0.1 )
)
// This Voice will sing 2 octaves above the Foundation Voice.
this.voices.push(
new BEEP.Voice( this.note.hertz * 4, this.audioContext )
.setoscillatorType( 'sawtooth' )
.setGainHigh( 0.01 )
)
// This Voice will sing 1 octave below the Foundation Voice.
this.voices.push(
new BEEP.Voice( this.note.hertz / 2, this.audioContext )
.setoscillatorType( 'square' )
.setGainHigh( 0.01 )
)
})