CODEWITHSUNDEEP
javascriptweb-audio-api
drenl
drenl

Reputation: 1333

WebAudio setTargetAtTime: formula to convert-time constant to seconds

I've found I like the sound of setTargetAtTime() applied to gain. So I'd like to do this:

 gainNode.gain.setTargetAtTime(0, audioContext.currentTime, timeConst) 
 oscillator.stop(audioContext.currentTime + timeConstToSeconds(timeConst));

So that the oscillator stops when the sound is functionally inaudible. What is an effective timeConstToSeconds() function for this?

And/or, what is an effective formula for the reverse operation? (input seconds, return time constant.)

Upvotes: 0

Views: 154

Answers (1)

Raymond Toy
Raymond Toy

Reputation: 6048

The spec tells you exactly how setTargetAtTime works: https://webaudio.github.io/web-audio-api/#dom-audioparam-settargetattime

As a rough general rule, these kinds of exponential approaches are generally considered to have converged to the final value after 5 or 10 time constants, so

function timeConstToSeconds(t) { return 10*t; }

Change 10 to some other appropriate value for what you consider to be close enough.

Upvotes: 1

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