Is this the new Drain Tuba?

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Tom Smit
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Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Is this the new Drain Tuba?

#2 Post by Tom Smit »

:lol:
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Seth
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Re: Is this the new Drain Tuba?

#3 Post by Seth »

Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Rich4349
Posts: 855
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Is this the new Drain Tuba?

#4 Post by Rich4349 »

I built a bass reflex out of a 40" long piece of maybe 20"? wide PVC. The calculated ports were so damn big I tried running them OUTSIDE of the enclosure. Does that screw things up? (I mean screw them up any more than using BR in the first place. :lol: )
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

AcousticScience
Posts: 148
Joined: Tue Jan 20, 2015 4:37 pm

Re: Is this the new Drain Tuba?

#5 Post by AcousticScience »

I've only found problems with simulating bass reflex when either the port is long enough to have its own resonance in the pass band or the box is deep enough that the back causes a half wave cancellation in the pass band. Beyond about 2.5 feet deep.
I mean if you have a port as wide as the box it becomes a tuned quarter wave enclosure. If you flare it enough it's a rear loaded bandpass horn!
As for using a bass reflex instead of a horn, well when you start getting small like a tuba 24 the horn becomes less efficient - e.g. only 90dB efficient (low bass) when a bass reflex of the same size is 98 dB efficient which is why I didn't go with a single tuba 24 in my limited space vehicle, but if you have room for the bigger horn cabs go with them.

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