making a MMTTMM version of an MTM design

[tech.knockout]

Is it easy to modify the crossover of a MTM design to suit a MMTTMM version of it.

[foo]

i think it's easier to build MTTM ones

[joe carrow]

As I understand it, the hard part with converting an MTM design to MMTTMM would be the trouble you will have with interferance between the drivers. Higher frequencies require that the drivers are closer together- within a certain fraction of a wavelength of that frequency. Having two tweeters could give you trouble- and if the crossover is high enough, the two groups of mids could be too far apart.

The MMTTMM starts to look like a line array- I'd suggest reading about line arrays, comb filtering, and that sort of thing. I haven't had trouble with this kind of thing before- it seems to be the one area in speaker design that I've actually paid attention to

IMO, the best bet here would be to get a more efficient tweeter to match the improved sensitivity due to doubling the number of woofers, and then google for something like a crossover calculator

Good luck with your project.

[MethMan]

If you want to double speakers in existing design, answer is NO. If you want to design your own, imho there is no reason to do it because of wasting money and really difficult problems to solve.

Meer MTM

[RJ]

Why two tweeters???
The center to center spacing can't be achieved with 99% of the tweeters out there. With 4 M's the sensitivity would go up from 4 to 6 db. Just match one tweeter at that sensitivity.
Read Jim Griffins white paper on line arrays . It'll explain the problems of speaker size and placement and sensitivity gained by more woof's;
http://www.audiodiycentral.com/awpapers.shtml
Also Bottlehead has built quite a few MMMMT's;
http://www.bottlehead.com/valve/wham...les/page2.html

If you model your design on Baffle Diffraction Simulator you'll visually will see the problem of sound cancellation and re-enforcement;
http://www.pvconsultants.com/audio/d...ownloadbds.htm

[BAM]

There are some designs out there that use two vertically-arrayed tweeters, and the result is vertical dispersion control. Not all that important, and kind of a novelty, but that's what it does.

[BlueWizard]

I'm curious, why not a WMTMW setup; in other words, a 3-way system? That is actually quite common and you should be able to find design and modeling discussion about this.

I believe there might be a long discussion here somewhere covering the entire design and modeling up to the final design for a Dayton Reference WMTMW system.

Just a thought.

Steve/bluewizard

[bzfcocon]

Also a 0.5MMTM0.5M should work well (2.5 way MTM). Have not seen such a design sofar though, 3 way seems more common.

[jotom750]

Hi.
I was thinking of twin tweeters also, I have read that there are problems involved, but some hi end designs do use multi tweeters and I have not found a 94 to 96 db at 1w/1m tweeter at all, let alone at the cost of two Vifa D26NC55 ($29 each).
If there are please tell.
Thanks.

[sreten]

Originally posted by tech.knockout
Is it easy to modify the crossover of a MTM design to suit a MMTTMM version of it.

Hi,

The short answer is yes it is easy, but you will get a lot more lobing.
You change the MTM components to suit double or half impedance.

/sreten.