Historically, Chrome implemented dezippering such that when the value setter of an AudioParam was used, the value was not changed instantaneously. Instead, an exponential approach equivalent to setTargetValueAtTime was done. The actual time constant used was never specified and depended on the AudioParam. With the spec change in https://github.com/WebAudio/web-audio-api/pull/393, (Sep 2015), all dezippering was removed from the spec. Dezippering will be removed from Chrome.
Docs: https://webaudio.github.io/web-audio-api/#audioparam-transitions https://github.com/WebAudio/web-audio-api/issues/76#issuecomment-107679878 https://github.com/WebAudio/web-audio-api/pull/393