If you're playing places with only vocal PA, you don't need that much firepower, and everything will sound like garbage if you just try to out loud your bandmates.
If you want your band to actually sound good, research live sound techniques and spend some of the money you were going to use on a too big bass rig on getting a set of PA mains and subs that go well together. Having bass, drums, etc... in the PA will go a long way towards making your band actually tolerable to listen to.
I would also say, if you DON'T do that, "stereo" on bass is going to probably get lost in the room anyway. The subway cabs I gather are all grouped pretty closely in terms of frequency response, so you won't gain much with a pair of 2x10/1x15 stacks. You would get more out of 4 2x12s I think. If the V12s can biamp then you could look into some sub specific low tuned 15s or 18s and go with 2x10s or 2x12s on top. Again, this becomes complete overkill in a bar where the drums aren't in the PA. Generally speaking, a single good quality 4x10 should pretty much keep up with acoustic drums, even in a fairly loud metal band.
Also, just so you know, you don't have to have Mesa cabs just because you have Mesa heads. Feel free to use whatever brands you want to use together. The only caveat I would make to that is you probably want to keep all the cabs more or less in the same brand and/or line. A mesa 2x10 and an eden 2x10 and an ampeg 15 and an swr 15 or something isn't really a recipe for success.
Anyway, to wrap up, if you or your band aren't going to roll with your own PA with subs, the equivalent of a 4x10 or 2 (like 2 2x12s, etc...) is probably plenty. Also, guitarists should really only be using a 2x12 each in a situation like that, and more like 50w than 100. Otherwise you're pretty much all giving the finger to your drummer and your singer (especially the singer). If you all get into a volume war, the vocals will basically ALWAYS be muffled, drenched in feedback, and just generally sound awful. So before blowing 1000s of dollars on JUST bass stuff, you should really look into dedicating yourselves to bringing a PA to shows if you actually want to put on a well produced show and not just a noisefest. Take it from this guitarist/bassist/keyboardist/sound guy.
Hello Omega Monkey,
Thank you for your response and advice. You raise several excellent points. Perhaps, I should have done a better job in describing my application for this rig in my original post. I’m always conscious of not drowning out my bandmates. Especially, our singer. However, my drummer and guitarist are loud and I could not cut through with a single Epifani DIST 410, so I added a UL3 310 and went with QSC GX-7 to drive the cabs. My preamp is an Aguilar DB680. This rig is a bit too HiFi for the style ARIS is playing and we do have have instrumental section that are pretty heavy. It’s during these sections that I need to elevate volume, yet retain low B fidelity and articulation and also have some midrange cut for two handed tapping, chords, runs and swells with FX. During the vocals, we control our dynamics quite well and I even disappear from the mix at times.
Since we are opening shows or providing support for larger acts, we don’t have the option of setting up an auxiliary PA where we usually perform. We don’t play tiny bars. However, we do have 4 EV ELX floor monitors to make sure we hear clear vocals when we play clubs that don’t have stage monitors. If the PA is beefy enough, we chose to put in our guitarist who plays in stereo and some kick into the mains. My bass is rarely welcomed into the PA as there are not usually subs. So all the bass needs to be generated by my rig. I do use a wireless and go out front to hear the band mix and make changes accordingly. If the room get packed and there are bodies upfront blocking and absorbing the bass, I have been told by trusted musician friends that frequent our shows, that I’m not keeping up with the PA as it projects into the venue. When I turn up and EQ accordingly, I can blend into the room well. Since, the size of venue and quality of PA and experience level of the sound person varies widely, I need to make sure I have more power on tap rather than less. Its all about headroom for me and I want as much as possibly so my rig will work wherever we play.
I very much agree that blowing out band members and the audience with too loud of sound is a very bad thing. After three years playing the local circuit, we are no where near the loudest band in our scene. However, hearing health is important to me as well as the guys in our band. I personally walk the room before shows to thank people for coming and also to offer them earplugs. I mention we have loud passages in some songs and that we can get loud. Most don’t accept them, but those who do are pleased and usually come up after the set to say thanks and sometimes pick up some stickers or buy a CD. So, impactful dynamics are key to conveying our songs and having control over the necessary amount of volume (headroom) during our shows is required to make sure the bass is not lost in the room or over powered by the PA.
The Mesa Boogie house “rock” sound as well as switching from a Paul Reed Smith GG-5 bass to a Spector 5 should deliver the tones I’m after. After reading the TB replies and watching some great tone comparisons on YouTube, I’m leaning towards a Subway 215 with a 212 on top. The Titan has a 2 Ohm switch on the back, so aim assuming it can handle the 2 Ohm load. Both Titans are receiving power supply and thermal updates at the factory. I plan to play through some Subway cab pairings when I pick up my amps. I will come back and share my findings to help other who may be in a similar situation.
As for splitting the bass cabs left and right of the drums to run in stereo, I do now realize that in larger venues with a proper PA that this setup is not acoustically ideal. The split cabs would create issues for the stage mix. So this is no longer something I’m interested in doing when we play bigger venues with full PA. I’ll stick with making my sound in one area and projecting from a vertical array cabinet stack.
In the smaller venues without full PA we play, my guitarist has problems hearing me at times and the same happens for me not hearing him as well as I need at times. We discussed both of us splitting our cabs left and right of the drums. The idea is that hearing each other better will help us self-balance our mix. For the audience, we’re thinking it will be just like listening to a big stereo system with a live drummer in the middle. The guitar is already stereo and mostly in the PA and we want to keep the stage monitors with vocals only. So the split stereo set up seemed like a good idea to try.
Again, thank you for your response and advice. I very much appreciate your point of view and it has made me rethink how I put this new rig together.
Kind regards,
Michael
just my 2 pennies. 
