How low will two Tuba 36 ‘Slim’ version subs stacked go?

[DeonC]

Hi guys

My question is simply this- how low will a pair of Tuba 36 ‘Slim’ version subs stacked one on top of the other go ITO bass extension? I am talking of the verticle baffle system. It says the following on the website: 'Build the vertical baffle version for extension to 15 Hz...'. I am thinking of two subs measuring 36 x 36 x 20 inch (HDW) stacked on top of each other to measure 72" tall. Just wondering...

Enjoy,
Deon

[simon5]

15 Hz, I'm not believing that.

15 Hz needs an excessively large horn, even if corner loaded.

[GM]

Greets!

FWIW, someone mentioned to me that his Table Tuba has a ~13 ft pathlength, which sitting on a large, massive surface equates to a ~15 Hz Fc, so ignoring the room, how low it goes before rolling off to Fc is a function of mouth area. If his slim version is functionally the same, then two with a combined 72" x 20" mouth sitting on and perpendicular to said surface unloads at ~71 Hz, so figure a peak at ~35 Hz before rolling off. Factor in a corner, a hyperbolic flare, and two drivers with the 'right enough' specs and it should have no problem getting to 15 Hz in-room, but a driver small enough to fit in such a compact box won't have any real power handling down this low, so I seriously doubt it will have any real 'grunt' below ~35 Hz other than what the room provides, which should still be quite enough to rattle the house since the starting efficiency will be fairly high.

Frankly, as cheap as large sub drivers and amp power is these days, I'd just as soon have a few kW and couple of 'hummer' drivers in a less obstrusive package for sub duty.

GM

[Bogie]

Yeah - I was at an outdoor gig this past weekend, and four 18" Peavey low riders in slot-port boxes pretty much did the trick out a fairly good distance.

Didn't reach out and slap you, but you know something? It sounded like music.

[hakalugi]

Originally posted by simon5
15 Hz, I'm not believing that.

15 Hz needs an excessively large horn, even if corner loaded.

It's not fully horn loaded at 15hz (based on mouth size or path length) but there is response - see this image another BF forum member made:
http://www.ofgb.org/reference/music/bill fitzmaurice/plots/tuba36 - outdoors in half space.jpg for actual response down to 15hz

Originally posted by GM
Greets!

FWIW, someone mentioned to me that his Table Tuba has a ~13 ft pathlength, which sitting on a large, massive surface equates to a ~15 Hz Fc,

actually it's 17hz for the standard size TableTuba (30x30x16) but it's long path lenght and smaller mouth (it's not a 'full-face-mouth' like original Tuba series) mean it 'must' have at least a wall for 1/4 space loading per Bill.

so ignoring the room, how low it goes before rolling off to Fc is a function of mouth area. If his slim version is functionally the same, then two with a combined 72" x 20" mouth sitting on and perpendicular to said surface unloads at ~71 Hz, so figure a peak at ~35 Hz before rolling off. Factor in a corner, a hyperbolic flare, and two drivers with the 'right enough' specs and it should have no problem getting to 15 Hz in-room,

i think you're mixing Table Tubas and the mouth size of a pair of T36s as described (or i'm misunderstanidng you)

but a driver small enough to fit in such a compact box

the normal TT (table tuba) does have a small driver space - i use an HL10 and it's tight. I send it about 360 watts from 1 ch. of power from an QSC RMX 1850 HD. but with about 98db/1/1m sensitivity, doesn't need too much power

But i think you're confusing them again. The Tuba 36 has a huge amount of space internally, whther you use the horizontal or vertical baffle - it's still 'spacious' -- in the poster's 20" wide version, you could fit one of the recommended drivers: http://www.wwbw.com/Eminence-Magnum-...-i505425.music which takes 700 watts RMS. In the 'normal width' 30" model, going with 2 x 12" drivers, or a 36" wide with 2 x 15" drivers.

But if you go with a 20" wide one, per bill ". If you build the cabinet narrower than 30 inches use the horizontal baffle, otherwise response will be compromised. "

won't have any real power handling down this low, so I seriously doubt it will have any real 'grunt' below ~35 Hz other than what the room provides, which should still be quite enough to rattle the house since the starting efficiency will be fairly high.

Frankly, as cheap as large sub drivers and amp power is these days, I'd just as soon have a few kW and couple of 'hummer' drivers in a less obstrusive package for sub duty.

GM

you're leaving out one thing: quality. Bill's TT is my first folded horn sub, but I've built sealed Qtc .5, then .7 for dual A/D/S 12's, had HSU, SVS, and Sunfire in my house for extended periods. Played around with a vario-vent, did ported per Win ISD, and even some 4th order BP for fun.

And nothing sounds as good with my fronts as the Table Tuba I built. The 13' path length means I need to tell my Pre/Pro it's 13 feet 'farther' away than it realy is -and some EQ (from my BFD) to flatten it out- then it's the tightest fastest bass i've ever heard in my house.

I'm building a 48" wide 'table tuba' with a 21' path length, with an Fc of 13hz. It'll have space for 2 x 12" drivers with 1200 watts RMS between the 2. And as far as being unobtrusive - i'm making it the riser for my 2nd 'row' chair - so the only person that will know where it is the owner of the bum sitting over the side-vent getting blasted in a very special place.

This is a DIY forum, i say give it a shot, you'll be surprised with what you hear

[simon5]

Your link isn't working.

BTW, any box have response at 15 Hz... the way you define it.

[hakalugi]

his site appears down. it showed a 1/2 space plot (in a field by his home i believe) with several response sweeps.

"the way i define it" - not sure what that means...

but since it starts off so sensitive, it does play usable down there. but if "sub 20hz" is your goal, build 8 TableTubas (TT) and line your front wall with them, making a 30"high bench with the mouth facing the front wall to floor edge.

note: traditional horn mouth area vs. Freq equations have to be modified b/c of the larger rear chamber in the tubas (not TT, but the traditional ones). Browse Bill's forums, but basically, he claims (and has measured) an "additional octave" of response below what would normally be expected b/c of this larger rear chamber and the flare config.

i suggest you try one