I'm planning on building a pair of Tuba 30s with 12 inch drivers (probably the eminence kappalite 3012lf but I'm open to suggestions) and I'm stuck on what width to make them. I understand that you get more output from having a wider cabinet (max 30") but at what point does this become impractical? Assuming I have the vehicle to transport them, what are the practical doorway limitations that one runs into? It need to be able to get these into club and warehouse spaces but also for the occasional house show. My running assumption is that in most places in the US at 23" cab can make it anywhere and a 28" is going to make it through 90% or the doors one would encounter. Am I on the right track here? Has anyone built at 28" and regretted it?
Having been where you are now, I just wanted to share a few findings regarding the T30's.
For a single person, 24" is nudging the upper end of size and weight to making for manageable cabs for maneuvering through door/hallways, and lifting into the back of vehicle/trailer, or lugging up stairs. I built with marine ply so my cabs are a bit heavier, so premium drivers saved some weight. IIRC mine weighed in at 36kg a piece, but I built them with heavy duty castors which adds some weight (but makes them easier to move). 2) Driver:
I recommend premium all the way. Single loaded, medium width cabs are the go. Two of my single loaded 24" wide cabs will outperform one double loaded cab at max width, making them more cost efficient, and easier to move. Don't waste your time with cheap drivers, you'll kick yourself at the end. The T30's hit pretty hard indoors, but to give you an idea outdoors I also have 2 OT12's and they happily keep up with the 6 T30's. So in my opinion, 3012LF would be the minimum spec driver, I'd also consider the 18Sound premium driver as it will give you a little more headroom and allegedly better thermal efficiency. Depends how hard you plan on running them; if they will be run at full noise for hours on end, definitely consider the extra insurance that the 18sound drivers will offer. 3) Tuba or Titan:
You're onto it. Yes the T39 outguns the T30 above 38hz, but that’s raw cab output being measured. Once you factor in your high and low pass filters and your EQ, suddenly the T39 is looking a lot weaker for electronic music with a 45hz cut off (with 2 cabs). Nothing worse than hearing your basslines cut out on the lower notes. With 2 T30's you can happily get to 35hz, which in my opinion is still not quite acceptable but that's just the music I play - you need to measure your content to decide what you need. This is not to bag out the T39, but it is the wrong tool for the job if you're trying to hit sub 45hz.
4) T30 or T45:
While it's true you can't V-plate the T45's, a V-plated stack of T30's does take up a lot of room, a consideration for indoor work. I sometimes think the T45 may have been easier to move around etc, but wheels make any cab easy to move. If you wanted to make them lighter, skip the castors and use a dolly. I do like the form factor of the T45 but haven't yet been stumped when placing the T30's. Most of the time they face a corner or a wall. For me, the clincher was the ability to V-plate for a worthy boost in performance and efficiency.
If you have any other questions about living with the T30's feel free to ask.