Hi, I've just replaced my front centre speaker with a new Kef Q9c. I've noticed however that there seems to be a buzzing coming from it when certain low frequencies are played through it. I moved the speaker onto the floor and played various things through it which contained the frequency that seems to be causing it. I found that the buzzing seems to be coming from the resonator (think thats what it is called) at the back of the speaker. It is hard to describe what it sounds like but it is like a pulsing vibration. I also tried placing one of the bungs that came with the speakers in it but it didn't seem to help. Could this be because the speaker is not yet run-in properly? I'm almost certain the Q9c that I had on home demo did not exhibit this problem (although this one was not brand new). Hope this description makes some sense Thanks in advance for any help.