I am running on Onkyo 705 with 5 channels (no .1 and I probably do as much 2 channel as 5...). While watching The Dark Knight Rises Blu-ray, I noted a few instances where my front left Sierra 1 and to a lesser extent the right seemed to have a slight rattle (I was attributing it to additional "detail" in the background of the movie and not a rattle). The element that has me concerned however is when Fox takes Miranda on the elevator/platform down to the reactor and the elevator hits bottom/stops. A heavy bass signal is sent which made the speakers (and yes, it came from the speakers and not the room) --esp. the front left-- sound like a rattle was coming from them. This is the secondary concern however. The primary concern is that the speakers (left front in particular) created a sound with that base signal similar to what one would expect small speakers from a child's toy (or inexpensive external computer speakers) to create if hooked up to play one of the lower registers of a pipe organ or bass heavy rap etc.

Initially, I wondered if it was actually the sound editing, but playing it at a very quiet level seemed to resolve this. Volume was set at 70 (for those with familiarity-- I know, there can be a lot of variables). Suffice it to say that it was not exceptionally loud and the distortion could be replicated at about 63 up.

So the questions:

1) MOST IMPORTANTLY: Does any of this seem to suggest that my speaker may in fact be damaged OR may have suffered damage? I have never heard this from these speakers, but then I have never watched this disc until tonight. I would not expect moderate volumes from a reasonably powered receiver and outstanding speakers to do this.

2) What is anyone's guess as to what happened?

Thank you for knowledgeable insight.