message: not necessary to set frequency in constructor
diff: @@ -97,13 +97,11 @@ export class FrequencyShifter extends Effect<FrequencyShifterOptions> {
  this._sine = new ToneOscillatorNode({
  context: this.context,
  - frequency: options.frequency,
  type: "sine",
  });
  this._cosine = new Oscillator({
  context: this.context,
  - frequency: options.frequency,
  phase: -90,
  type: "sine",
  });
  