public void setDirectional(boolean directional) {
        this.directional = directional;
        if (channel >= 0)
            getRenderer().updateSourceParam(this, AudioParam.IsDirectional);
    }
Set the audio node to be directional.
Does nothing if the audio node is not positional.
<br>
After setting directional, you should call
{@link AudioNode#setDirection(com.jme3.math.Vector3f) }
to set the audio node's direction.

@param directional If the audio node is directional
jme3-core/src/main/java/com/jme3/audio/AudioNode.java