I'm watching this at the moment on BBC HD, and my bass speaker is rumbling constantly despite there being no such sound on the show. Anyone else getting this, or is my setup wrong?

Strange as it is otherwise fine on all other programs. I'm inclined to blame the HD broadcast.

I use it as 5.0 - decent speakers and no sub.

No obvious extra bass and my fronts go down to near sub levels.

Can't have a sub as Castle have gone bump

I noticed there was a lot of low level bass - but i'm fairly certain it was to symoblise distant explosions - plus i'm sure some of it was incidental music.

My bass speaker isn't that sensitive, most tv shows won't make it rumble unless it is really low or loud, like explosions. Yet in simple conservation scenes it was pounding away non stop. Was really over the top.