[quote name='NancyJohnson' timestamp='1493029201' post='3284887'] 
I'm sure we're all familiar with this type of chart: 
 
Lovely, isn't it? 
 
Thing is while I'm sure Phil's post is of some interest, I did start to blur over.  (Sorry!)  Thing is, these sort of numbers are not unlike the motor vehicle manufacturers claims of peak performance for their vehicles; unrealistic in the real world. Ever had 50mpg from your Honda CR-V?  No me neither. 
 
When I turn up for a gig (like last weekend), where we have no monitors, little more than a vocal PA running the gig, I despair.  Room was about 45'x30'.  The sound guy, bless him, is saying we need to turn down, the drummer can't hear me (and he's sitting less than a metre from my gear), I can't hear me or anything else apart from the drums.  I'm sorry, but a 1x12 isn't going to work now, is it?  If, however, I was playing in a jazz trio, acoustic piano, drummer on brushes, I'm sure a 1x12 would be fine. 
[/quote] 
 
Kill the guitarist(s) and all will be fine..