"I'm adamant that the only thing going through the PA will be vocals as I believe most bands are too loud."
FWIW, I would consider it more of a 'balance and control' issue by putting everything thru the system, than simply a volume thing ..
... with that said, I also had to make the same decision, and opted to go with a pair of Yamaha S115IV's for the mains ... had I decided to go with a sub, I would have used 112/horns ... it turns out that I found a second pair of S115's just after I found the first set used, and got them as well, even though we may not be using 4 of them on a regular basis ... I guess I just wanted to keep things simple, no crossover, single power amp for mains, etc ... my thought is that if we start needing more, there are plenty of sound outfits around with complete systems for rent that supply everything if that occassional need arises, and they should have the ability to dial everything in properly without us having to deal with it ...
... so, to be efficient and affordable for what I can do as one person, I opted to go the no sub route, and decent stuff maybe a little older and used ... but then, we are also playing 50/60/70's music, so that as well had an affect on the decision .. we played this stuff 40 years ago with a couple padded 410 Kustom columns, or if the space warranted it, a half dozen Altec Voice of the Theates stacked up and never even thought about subs ...
The type of music that you play probably affects your choices and needs as much as anything, and then when you add in monetary restrictions, and if you have a person capable of being out front to properly run it all matters too ...
Again not ideal, but I actually have our bass drum into my Peavey practice amp in front of the drum ... some may frown on it, but it adds some crispness to the kick and the amp is along for the 'just in case' situations that may arise anyhow ... none of it is optimal, but sometimes you just make the choices based upon what you have and what you can afford to do ... I will now defer to those on here that have forgotten more about sound reinforcement than I will probably ever know, just thought I would share my thought process on the same question ... and again, JMHO
