HFL causes speaker rattle?
 

When using my SE T616 with the HFL (which, btw, works extremely well) I notice a speaker in the front rattles. This (obviously) occurs when the party on the other end is talking. Varying the volume does not seem to make a difference.

It is a little annoying. I do not have this problem when listening to the radio/CD.

Is this something other people are experiencing?

Other than this "rattle" the car is silent (no rattles or noises).