Tuba 18 driver/crossover questions

[telecast]

I'm the proud new pappa of a 1976 Pioneer SX-650. Currently running some older cabs I had laying around unused for years and years, some Sony bookshelf and a Optimus down-firing 12" sub. They actually sound halfway decent after I installed new drivers, but I'm pretty sure I could do better.

I'm thinking a Tuba 18 and a set of short SLAs would do the trick for me, but have some questions. My current sub is passive. It has a dual crossover built in with satellites out. You feed both sides of the amp into a DVC subwoofer via the filters, then back out to the tops. I really like this setup because it's easy and doesn't involve a subwoofer amp, and since there's (obviously) no sub line out on the receiver I'm kind of stuck anyway unless I buy a high-dollar sub amp with low and high inputs.

Questions are pretty straight forward:

1) Is there a suitable DVC driver that could be installed in the Tuba, or, is there another way to accomplish the same setup?
2), Or, could the Tuba be built with dual drivers, each fed from one side of a similar dual crossover?

and

3) What would the recommended crossover point be for the mid/tops assuming short SLA?

Maybe these questions have already been answered in more recent plans, the last set I have is from '06 or '07, so I'll need to buy new plans for both cabinets.

Thanks!

[Bill Fitzmaurice]

There's no reason to use L/R signals with a sub. Content below 80-100 Hz has been summed to mono since the 1970s.

[telecast]

That scares me.

Assuming my receiver is summed, how would I connect it and the tops?

[Bill Fitzmaurice]

It's not the receiver that's summed, it's the content. The same material is on both channels. Therefore only one channel needs to be connected to the sub.

[telecast]

Ok, so you're saying run side one to the sub and then on to the mid/top, and then run the other mid/top direct to the amp? Wouldn't that put a 4-ohm load (given 8ohm cabs) on one side an 8 on the other with no crossover?

[Tom Smit]

Ok, so you're saying run side one to the sub and then on to the mid/top, and then run the other mid/top direct to the amp? Wouldn't that put a 4-ohm load (given 8ohm cabs) on one side an 8 on the other with no crossover?

The "imbalanced load" doesn't hurt anything, unless the amp channel cannot handle a 4ohm load.

[Bill Fitzmaurice]

Ok, so you're saying run side one to the sub and then on to the mid/top, and then run the other mid/top direct to the amp? Wouldn't that put a 4-ohm load (given 8ohm cabs) on one side an 8 on the other with no crossover?

No, because you still need a crossover between the sub and the main, which is another subject entirely. A plate amp for the sub would be better. With the high sensitivity of the T18 it need not be more than 75 watts.

[telecast]

Ok, so you're saying run side one to the sub and then on to the mid/top, and then run the other mid/top direct to the amp? Wouldn't that put a 4-ohm load (given 8ohm cabs) on one side an 8 on the other with no crossover?

No, because you still need a crossover between the sub and the main, which is another subject entirely. A plate amp for the sub would be better. With the high sensitivity of the T18 it need not be more than 75 watts.

That's essentially what I was asking, but I prefer to run the amp the way it has been. I'll figure it out, I may just reuse the existing crossover and load it into the Tuba. it has all the connections and hardware already there. I found a similar DVC sub on PE that should work. The amp is rated at 35w, plenty for my use.