Can a ML-TL be done as a 2.5-way?

[Dirk]

There's one problem with InDIYana (and I assume other events like them). An annoying catalytic effect. I now have 3.5 projects lined up.

Once upon a time, Ed (Lafontaine) penciled up a ML-TL MTM for me. I'm going to make that happen since I'll only be out the cost of crossover bits (I have plenty of suitable tweets on hand). The dimensions, though, were a box that was 36"H x 7.5"W x 10"D. The tweeter location would have been 13" down from the top of the box. That means the tweet would be just 23" off the floor. Raising the whole thing up would make for some uncomfortably tall speakers.

Could the ML-TL work just as well as 2.5-way? I can't see any reason why not (as long as the woofs were equidistant from that 13" center point), but I figured I'd ask.

Thanks all!
D.

[Paul K.]

When an MTM is configured as an ML-TL (or tapered TL or ML-TQWT for that matter), the line's design center (the mid-point between the two midwoofers) is the same as the tweeter's center. So, if you want to build an ML-TL using a TMM arrangement, the design center for the line is, again, the mid-point between the two midwoofers. In either an MTM or TMM, the line is designed as if there's a single midwoofer, but having twice the Sd and Vas, located at the design center. Of course, whatever Ed modeled for you might have to be revisited if the design center for the TMM isn't the same as that for the MTM relative to the line's length, area, etc., and you'll need a different crossover for the 2.5-way TMM.
Paul

There's one problem with InDIYana (and I assume other events like them). An annoying catalytic effect. I now have 3.5 projects lined up.

Once upon a time, Ed (Lafontaine) penciled up a ML-TL MTM for me. I'm going to make that happen since I'll only be out the cost of crossover bits (I have plenty of suitable tweets on hand). The dimensions, though, were a box that was 36"H x 7.5"W x 10"D. The tweeter location would have been 13" down from the top of the box. That means the tweet would be just 23" off the floor. Raising the whole thing up would make for some uncomfortably tall speakers.

Could the ML-TL work just as well as 2.5-way? I can't see any reason why not (as long as the woofs were equidistant from that 13" center point), but I figured I'd ask.

Thanks all!
D.

[Dirk]

When an MTM is configured as an ML-TL (or tapered TL or ML-TQWT for that matter), the line's design center (the mid-point between the two midwoofers) is the same as the tweeter's center. So, if you want to build an ML-TL using a TMM arrangement, the design center for the line is, again, the mid-point between the two midwoofers. In either an MTM or TMM, the line is designed as if there's a single midwoofer, but having twice the Sd and Vas, located at the design center. Of course, whatever Ed modeled for you might have to be revisited if the design center for the TMM isn't the same as that for the MTM relative to the line's length, area, etc., and you'll need a different crossover for the 2.5-way TMM.
Paul

I've got all that jazz. I didn't know if there was something strange about woofer behavior I should be aware of that would make 2.5 incompatible with a TL.

Ed listed the center as 13" down from the top of the box. The problem is that, if I wanted a 36" tweeter height, the top of the speaker would be 50"+ off the floor. That's what lead me to think about TMM. With a design center of 13" from the top, I figured I could snug the two midwoofers together tightly and still have plenty of room for whatever tweeter struck my fancy.

[Dirk]

By the way, it was a pleasure to meet you!

[Paul K.]

By the way, it was a pleasure to meet you!

It was good to meet you, too.
Paul

[curt_c]

I've got all that jazz. I didn't know if there was something strange about woofer behavior I should be aware of that would make 2.5 incompatible with a TL.

There are no constraints that I'm aware of. Certainly it should work as well, or better than a ported TMM 2.5 way.

Ed listed the center as 13" down from the top of the box. The problem is that, if I wanted a 36" tweeter height, the top of the speaker would be 50"+ off the floor. That's what lead me to think about TMM. With a design center of 13" from the top, I figured I could snug the two midwoofers together tightly and still have plenty of room for whatever tweeter struck my fancy.

Reconfigure the box topology to put the tweeter where you want it. For example, MJK's formulae suggest high taper TL's 'like' the woofers about a third of the way from the closed end of the line. Say for example, your line was 72" long and your folded it once to make it 36" tall. If you have the closed end at the bottom / fold at the top, the tweeter can be near the top, and the woofer offset (The center between the woofers will be roughly 24")will match the "1/3 of the way down the line" criteria.

C