CODEWITHSUNDEEP
javascriptweb-audio-api
drenl
drenl

Reputation: 1333

ToneJS: Multi-pitch keyboard entry

This pen uses the ToneJS library to play pitches on the computer keyboard. However, it can only play one note at a time. How can I code this to play multiple notes at once?

The code:

var keyToPitch = { "z":"C3", "s":"C#3", "x":"D3", "d":"D#3", "c":"E3", "v":"F3", "g":"F#3", "b":"G3", "h":"G#3", "n":"A3", "j":"A#3", "m":"B3", ",":"C4" }

var synth = new Tone.Synth()
synth.oscillator.type = "sawtooth"
synth.toMaster()

window.addEventListener('keydown', this.onkeydown) 
window.addEventListener('keyup', this.onkeyup)

function onkeydown(e){
synth.triggerAttack(keyToPitch[e.key], Tone.context.currentTime)        
}
function onkeyup(e){
    synth.triggerRelease()
}

Upvotes: 1

Views: 151

Answers (1)

fenomas
fenomas

Reputation: 11139

Oscillators in ToneJS are audio sources, and Master is the output that plays all the inputs connected to it. So to play multiple overlapping sounds, you just create multiple oscillators and connect them all to Master.

For the kind of demo you're linking to, a typical thing to do might be to make a fixed number (5, say) of oscillators, and rotate through them in turn when you want to trigger a sound:

var synthIndex = 0
function startSound(){
    synthIndex = (synthIndex + 1) % voices
    var synth = synths[synthIndex]
    synth.triggerAttack(/* ... */)        
}

Or similar. In principle you could make a separate oscillator for every pitch, but this would probably hurt performance in a less trivial demo.

Upvotes: 1

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