setDirectionalCone( coneInnerAngle, coneOuterAngle, coneOuterGain ) {

		this.panner.coneInnerAngle = coneInnerAngle;
		this.panner.coneOuterAngle = coneOuterAngle;
		this.panner.coneOuterGain = coneOuterGain;

		return this;

	}
Sets the directional cone in which the audio can be listened.

@param {number} coneInnerAngle - An angle, in degrees, of a cone inside of which there will be no volume reduction.
@param {number} coneOuterAngle - An angle, in degrees, of a cone outside of which the volume will be reduced by a constant value, defined by the `coneOuterGain` parameter.
@param {number} coneOuterGain - The amount of volume reduction outside the cone defined by the `coneOuterAngle`. When set to `0`, no sound can be heard.
@return {PositionalAudio} A reference to this instance.