MMTMM Why not more designs?

[ultrakaz]

I was reading about Zaph's new MMTMM at Zaph Audio. Based on his description it seems to combine the strengths of a line array without having to deal with a tower of drivers from floor to ceiling and having to deal with the problematic crossover to the tweeter (with regard to the comb filtering issue). The primary advantages are increased efficiency, impedence which is the same as if using a single driver, lower distortion, ability to play louder and controlled vertical directivity (vs an MT or MTM).

I did a search and there doesn't seem to be many designs. I like Zaph's design, but he recommends the use of a sub. I was thinking about 7" or 8" midwoofers for more efficiency.

A few questions:

Has anybody designed or done the research on how to go about designing one?

Has anyone actually heard a MMTMM, and if so what did it sound like?
What is the optimal midwoofer size?
Can a 2.5 design be easily converted to a MMTMM?

Thanks in advance.

[postalrat]

Are you open to TMMMM and MTMMM designs as well?

[HiFiNutNut]

Welcome to the new journey of speaker design and building. I started it 4-5 years ago and am just about to finish my first MTMWW speakers that are 100% of my own design.

Your question is very broad (I did the same thing a while back) and I don't know who can give you a reasonable answer without writing a book. The knowledge and experience required to design and build a pair of speakers are vast. My suggestion is to first read sufficient materials and study others' designs. You also need to sort out the difference between a subjective opinion / false belief or objective truth.

This is not to discourage you from doing it. It is a long, hard journey but at the end very satisfying and rewarding. Good luck with your adventure.

If you could narrow down your questions, I am sure a lot of experts in this forum will be keen to help.

Regards,
Bill

[PeteMcK]

'he recommends the use of a sub' - that is the main problem with this type of design, why use all those drivers when fewer well chosen drivers would cover the whole range?

[skogs]

Hi. Could you give me a link to zaph's design please? Couldn't find it.
I'm on the planning stage of building a bi-amped TMMMM, using four Vifa C17 mids and a Peerless dome tweeter. I have testet the four c17 together in small cabs, and i really love the sound of it, really punchy. I'm expecting this project to be very simple to get right, compared to a lot of other setups, mostly because of the bi-amping.

[5th element]

http://www.zaphaudio.com/ZA5/

[Telstar]

I'm also favouring the MMTMM design (woofers, apart, with one mid less due to cost and size issues). But I tend to prefer WMTMW commercial speakers and this reflected my choice.

[ultrakaz]

Skogs, what is the crossover frequency and slope (electric and actual) of your design? Especially, the bottom two midwoofs.

Pete the design fills a niche. Zaph did a poll a while back and found that people like narrow tallish versus big. Now I know why, at least for me. Okay, right now I'm running a 15" with midhorn and supertweet. I want to snake a narrow speaker in-between for non serious listening.

Hifinut, been in audio for over 25 years, even sold speakers in the 80s. Owned mostly every type. Never attempted to model a crossover on any software program, but have built 4 big speakers (and crossovers) in the last 10 years or so. I like designs that are efficient, with flat impedance, and with good power response. I just thought I might be able to convert Zaph's waveguide 2.5 design into a MMTMM.

Postalrat, (just got your monicker) no am interested in the MMTMM at this moment.

Thanks for the responses.

[skogs]

All four mids\woofers will be coupled in a serie-parallell-config, and will be playing the same frequencies. I'll probably go for an active 2nd order Linkwitz Riley with a simple BSC-circuit. I SHOULD do the same with the tweeter, except the BSC of course, but i want to try a passive xo on that one. (Otherwise i won't be able to use my main recievers amplifier).
XO will be somewhere around 2.5-3khz. (preferably as high as the woofers will allow.)

[Antripodean]

What about the Elsinore?