Sorry in advance for the long post, everyone.
Nicely written, if I do say so myself. The fact that you're really excited and pleased is all that matters. You now have the option of bringing one combo to a jam or rehearsal or add the second one to where a little more bass authority is needed.
You are correct indeed that you'd need ten times the power to double the volume. Think of it like you had been practicing through a 15-watt combo and one day brought it your BA-115, only to turn it on, play a note, and wet your pants. Now imagine you're enjoying the same 150-watt combo but get an itch to double its volume. That's right, you'd have to pony up to 1,500 watts to do it! Super wet pants, of yeah, but also incredibly expensive and unnecessary. With the addition of your second combo, you added +3 db in SPL, but more importantly, increase your surface area. That's why the perceived sound increase...you're moving a lot more air now.
So I played this afternoon, using my Vox SuperBeetle as I have the past couple of weeks and your great-looking rig influenced me into setting up my monster rig (for me), which will have little chance to be opened up, but I like the looks. It's one of a series of amp and Precision combinations that I've been taking pics of since June. I'm almost done, people! A number of those out there do not like the asymmetrical look, but I kinda dig it. check out my avatar. What's funny is the SuperBeetle is in the background looking kinda puny. I like it too though.
Is it time for a hardware post of our combos? I'd say, yes, it is! Post away, members, and have yourselves a great week. I'm down to seven days before I can just talk bass, amps, and what's on your Christmas wish list...
See ya,
FL
Thanks, FL!
TB has saved me so much effort, time and money by giving me such good information. I always try to post any insights from my limited perspective to help others that may be researching gear to buy. If you ever search "Roland Cube" or "battery powered amp," you're going to get to know me and
@Wasnex really well.
The truth of the matter is that I'll never need the 1500 watts. I play for fun. I'm not going on tour next week.
So your rig is the Fender Rumble 800 and extension?
...and what are the details on that Fender P?
Stacks of combos? Kind of defeats the intended purpose of a portable amplification solution doesn't it? Of course, with the MB212 combo i have, I'll never need to stack anything to get the volume i need to "wet my pants".
Another wonderful night at work. Three weeks now since my last day off. Bad weather caused a power outage here earlier today and the 25 year old computers that run our machines didn't like that one bit. Still dealing with issues including no network connection to the outside. Posting this with my phone. Gonna be a looooooong night.

Good thought!
I played bass for a few years, got rid of all my gear and rebooted about 3 years ago. The first time around, I bought the gear first and did a good job of guessing what I needed. This time around, I'm buying gear based on gigs that I actually ended up having.
I know it seems weird, but here's why I went from this 350 watt head + two 115 cabs:
to these two 150 watt 115 combos:
*****Don't get distracted by the Fender Rumble/Ampeg BA debate. Just look at the head/cab stack vs double combo stack. In fact forget brands at all. Pretend it's [insert your favorite combo by your favorite brand here].*****
I bought my first rig before I needed it and guessed pretty well what I would need. The head with two cabs served me really well. It sounded great and was super loud, but the truth was that I almost never needed the second cab. I thought about getting a second head and stand so I could set up a second rig at the practice space and keep one at home, but I decided to sell one of the cabs and just use the head and a single 115...which is what brought me to the 150 watt 115 combo.
This was great...except one time. I was playing outside at a party and we were having PA problems. For the most part, me and the two guitar players made up the difference with our amps. One had a 4 x 12 stack so no worries there, he put his amp behind the drummer so the drummer and everyone else could hear. The second guitar player had a small but powerful combo and had picked out a very appropriate stand so it was head height-and also happened to be aimed at the drummer. I rocked my BA115 into wedge position, aimed it at my face like I always do and blasted away all night!
The problem was that the drummer couldn't hear me. I didn't find out until later and had no idea because I could hear myself fine.
If I had it to do over again, I would take this double stack and put it behind the drummer like the guitar player with the 4 x 12. Having played that gig and having played my double BA115 rig, I am very confident that setup would have worked like a charm...and given me as close to the experience of an Ampeg stack as I'll ever realistically need.
At one point I also played an outdoor festival.
HUGE PA. BIG field.
maybe twenty people...all our friends...huddled as far away from the PA speakers as they could be without being rude or unsupportive.
There was an 8 x 10" backline provided and it was GLORIOUS. However, if I had been required to provide my own amplification, I'm confident that this double BA115 stack would have worked.
So the moral of the story is that, in the gigs that I actually played (as opposed to the ones in my head) I really only could have used a stack two times. However, it would have been consistently convenient for me to have a second rig to leave at the drummer's house so I only had to tote a bass to practice.
However, I am a very low level hobbiest bass player.
YMMV as they say.