tuba crossover point

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himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

tuba crossover point

#1 Post by himhimself »

In the beginning, I played around a bit, but not extensively, when I got my tuba/otop set-up going. Looking at my x-over, my tubas top out at 102hz, with the otops coming in at 110hz on my driverack, using the steepest LR slopes. When op checking my two new tubas using a tone generator, I noticed that the volume doesn't seem to really start to drop noticeably until quite a bit higher than 102hz. Like 120 and 130 still seem pretty similar, finally backing down substantially as the freq climbs into the 140-150hz range.
I've never noticed anything sounding off with how I've been running, but am wondering if I should set the subs to start rolling off quite a bit lower. Maybe 90 or even 80hz, to get them out of the otops bottom end.
Thoughts???
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Bill Fitzmaurice
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Posts: 28619
Joined: Tue May 02, 2006 5:59 pm

Re: tuba crossover point

#2 Post by Bill Fitzmaurice »

Since the Tubas are most sensitive above 100Hz you need to low pass them anywhere from 80 to 90Hz to get a flat summed response with the tops. If you had enough of them the Tubas would have a flat response right on down to 30Hz, but that would take perhaps sixteen of them. Even with four of them though you should see a flatter response into the lows than with two.

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: tuba crossover point

#3 Post by himhimself »

Thanks Bill, that makes sense. I will play around with lowering the LP accordingly.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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