code: function Biquad (options) {
  	if (!(this instanceof Biquad)) return new Biquad(options);
  
  	Through.call(this, options);
  
  	//init values for channels
  	this.x1 = [];
  	this.x2 = [];
  	this.y1 = [];
  	this.y2 = [];
  
  	//init coefs
  	this.update();
  }
docs: Biquad class
  
  @constructor