I've had my new PB 12 + for going on a month now I suppose.
I can't find settings that both please me and keep the thing from bottoming out on very low HT scenes. For the record, I am not a bass hound, nor do I listen very loud - typically the highest SPLs I see during movie playback are in the 90-100 range, average is 60's.
The gain is turned up approximately 1/3 of the way. After the AVR does its auto setup I have further backed down the LFE channel by - 2.5db.
Examples of scenes that make this sub bottom out - the rocketship ignition/take off from the Incredibles. King Kong landing on the ground in the scene where he defeats the final T-Rex. The opening scene from "Attack of the Clones" where the ship explodes.
I am generally thrilled by this piece of equipment. It does things like I never imagined. If I trim the config down to the point where these scenes do not cause bottoming, then I generally have little or no sub output in the more moderate low frequency range.
I have the sub set to the 20 hz tune. When I alter it to 16Hz or the 12Hz tune, the bottoming out effect is decreased, but not totally eliminated.
I can't even imagine what anyone would need the gain levels above 1/2 way for on this sub with it bottoming out at 1/3 gain.
I don't think my sub is broken in any way, but let me tell ya, it really takes away from those intense scenes when it suddenly sounds like your sub is exploding.
Your help appreciated.
Edit, I should say that other "bass impressive" scenes, like the Darla/glass tap scene from Nemo, do nothing other than make me grin from ear to ear. Same with the explosions in U571. Go figure.