function Filter(options, type) {
		this.options = {};
		options = options || this.options;
	
		var defaults = {
			frequency: 350,
			peak: 1
		};
	
		this.inputNode = this.filterNode = Pz.context.createBiquadFilter();
		this.filterNode.type = type;
	
		this.outputNode = Pizzicato.context.createGain();
	
		this.filterNode.connect(this.outputNode);
	
		for (var key in defaults) {
			this[key] = options[key];
			this[key] = (this[key] === undefined || this[key] === null) ? defaults[key] : this[key];
		}
	}
Filters used by Pizzicato stem from the biquad filter node. This 
function acts as a common constructor. The only thing that changes 
between filters is the 'type' of the biquad filter node.