public void setVelocity(Vector3f velocity) {
        this.velocity.set(velocity);
        if (channel >= 0)
            getRenderer().updateSourceParam(this, AudioParam.Velocity);
    }
Set the velocity of the audio node. The velocity is expected
to be in meters. Does nothing if the audio node is not positional.

@param velocity The velocity to set.
@see AudioNode#setPositional(boolean)
jme3-core/src/main/java/com/jme3/audio/AudioNode.java