I have a room that requires a sound bar. I have the sound bar mounted under a 47 inch flatscreen on an articulating arm with a sound bar mount.
My original set up:
Denon AVR 1912 (90w per channel) and Polk CHT400--This setup would overheat at 4db in 3 to 5 minutes using the AirPlay feature. Both the CHT400 and the AVR1912 were swapped out. If I played music via AppleTV not AirPlay, at the same volume it would take longer to overheat, but the AVR1912 always went into protect mode. The system only overheats with music, movies don't seem to work it as hard.
I have a Denon AVR1912 downstairs hooked up to some Bose Acoustimas Speakers and it runs fine at 4db (Apple TV, AirPlay, or whatever).
I pulled my Harmon Kardon receiver from the garage. It's an AVR235 (50w per channel) and it seemed to run the CHT400 at 4db without any issues. No HDMI, etc. So that is why it's in the garage.
I was convinced it was a combination of the of CHT400 and the AVR1912. Not wanting to lose AirPlay on the receiver, I swapped out my SoundBar for a Definitive Mythos SSA-42. This speaker is much heavier and deeper than the CHT400. I was impressed with the sound but I was able to easily overheat at 4db, pretty much the same amount of time.
4db is loud but that is probably where it would be at a party. If it overheated in an hour that would be one thing, but 5 minutes it kind of ridiculous.
Yes, I do have subwoofer. The speakers have always been set to small, 120Hz.
I don't think I need a more powerful receiver, since my old 50W HK AVR235 seemed work fine. Maybe I use need a different reciever, I just don't under stand why the AVR1912 works with the Bose Speakers and not with the Soundbars (I did try to swap them, I overheated the downstairs one)