_init() {
    var now = p5sound.audiocontext.currentTime;
    var t = now;
    this.control.setTargetAtTime(0.00001, t, 0.001);
    //also, compute the correct time constants
    this._setRampAD(this.aTime, this.dTime);
  }
Level at the end of the release.
@property releaseLevel