"What volume do you guys play at?"..."About 1/2 way"
Oh for FS! if you won't spend $30ish on a simple C weighted SPL meter then AT LEAST put a free SPL app on your phone!
As I said before, low frequencies need a lot of power. 100Hz will need 3 times the power into a speaker compared to 1kHz and that power input will double with each octave below 100Hz.
Then, a lot depends on the sort of bass sound you want. If you want twangy,clicky and bright then you will not need as much power as if you want very powerful, clean lows. bass E is 41Hz, B is going to be about mid 30s. They demand very good speakers, lot of cone area, lot of cone displacement, low distortion and a LOT of clean watts!
None of this is cheap.
This question is AT LEAST 60 years old. Once the lead guitarist got an AC30 (or a plexi) he HAD to turn it up. That pissed off the drummer who developed muscles. Vocal PA could not compete. In my 20s there were bands in a lot of pubs. Singer,2 guitars, bass, drummer...you NEVER could hear WTF the singer was going on about!
"Proper" musicians (and some "rockists") learned eeeventually to sort a good balance. Look at the old "big bands"? All those trumpets and saxes for ONE drummer and he wasn't working that hard.
Dave.