Speaker designs – MTM vs. TMM

Discussion in 'Speakers & Subwoofers' started by Panther_B, Apr 17, 2005.

  1. Panther_B

    Panther_B Auditioning

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    Hello everyone.

    I've noticed that most floor standers and bookshelf speakers have an M-T-M array.

    Is there a technical reason why these speakers are more popular than the T-M-M designs?

    Do the M-T-M speakers measure better (i.e. Flatter on/off axis, less distortion, etc.)?

    Or is it a visual thing? Do people just prefer the look of M-T-M designs more than T-M-M designs?

    Thanks for your help,
    B
     
  2. Michael%B

    Michael%B Auditioning

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    thats all i really know. i have no arguement for either but thats from dan wiggins. so i am assuming that it is easier to design a crossover for a mtm rather than a tmm.

    MIKE

    MIKE
     
  3. John Garcia

    John Garcia Executive Producer

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    I've been reading a lot about this recently. It is definitely not a visual thing, and it's not so simple to describe, since there are a lot of variables. I believe an MTM is actually one of the hardest designs to implement correctly - it seems simple, but it isn't THAT simple. Off axis can be a problem due to the fact that you have the two equal nulls to either side - in a vertcal MTM though, those nulls are generally not going to yeild a big affect at the listening position because they are above and below it, though it will mean placement is important. For a horizontal MTM (center), off axis can be a big problem, depending on your seating arrangement. X-over design should be similar, since you can still end up with the same sort of "comb effect" that can result from having two drivers playing the same frequencies, though the null(s) are not in the same orientation.
     
  4. Ron T

    Ron T Stunt Coordinator

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    There are far more TMM designs than D'appolito.
     
  5. David Bikeman

    David Bikeman Stunt Coordinator

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    While D'Appolito has designs that are MTM, most MTM's are not D'Appolito.

    David
     
  6. Panther_B

    Panther_B Auditioning

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    Thanks for the info so far.

    Although I'm not a speaker designer, based on what I've learned, I agree
    with Dan Wiggins from Adire Audio. But...

    There are so many D'appolito designs out there. So I wonder if I'm missing something. Even SL used a M-T-M design on his Phoenix speakers. I can't help but wonder why.



    Written by John Garcia
    “I've been reading a lot about this recently. It is definitely not a visual thing, and it's not so simple to describe, since there are a lot of variables...”

    Hello John.
    Could you describe the variables? Could you post a link(s) so I could read more about it? Thanks.



    What I really want to know is...
    Do M-T-M designs have any advantages over T-M-M designs? Lets assume that both speakers are floorstanders, good designs (no technical flaws), and they are the same hight.
    Is one design a winner over the other in terms of good sound (accuracy) and/or cost to implement correctly?

    Thanks again for the replies.

    Enjoy,
    B
     
  7. Panther_B

    Panther_B Auditioning

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    Written by David
    “While D'Appolito has designs that are MTM, most MTM's are not D'Appolito. “

    Hello David.

    I didn't know that. Could you describe the difference between the M-T-M and the D'Appolito?

    Thanks,
    B
     
  8. Ron T

    Ron T Stunt Coordinator

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    I sure didn't know that either David. Care to enlighten us heathens?
     
  9. Max F

    Max F Second Unit

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  10. Panther_B

    Panther_B Auditioning

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    Max, thanks for the link.

    If those guys are right, it seems that it's easier to design a good crossover for a M-T-M speaker. But the speakers need to be taller to get the tweeter at ear level.

    Acoustically, there doesn't appear to be a clear winner. Both designs can sound good (accurate).

    Could anyone confirm this to be true? Thanks.

    Enjoy,
    B
     
  11. John Garcia

    John Garcia Executive Producer

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    Well, I don't see where anything there would lead one to believe the x-over design is simpler for one or the other, or really give a sound advantage over the other either - as one guy said in there, it's all about the execution. The considerations are different for both.

    I don't have hardwood floors, and I have vaulted ceilings, so I don't have big issues with floor or ceiling reflections. I have stands that yeild nearly perfect height for my seating position for critical listening. This type of speaker can be very picky about placement, IMO, moreso than a TMM (which I had prior to these). I noticed this right away with my current MTMs - the sweet spot took me a few days to really dial in.

    I chose my speakers (GR Research A/V-2) specifically because of their midrange clarity, owing much to the designer's ability to know exactly what to listen for and measure for, and how to build a x-over that is very well suited to the drivers. Again, it's not as simple as it would seem to design one of these guys just right.

    I don't have a link to online info; I've been reading the Loudspeaker Design Cookbook v6 on MTM/Di'Appolito and THX speaker designs recently - I'm not a speaker designer either (though I have designed and built my own subs before), I just find the theory behind speaker design interesting.
     
  12. Chu Gai

    Chu Gai Lead Actor

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    Absolutely. If anything is true, it's that 'Any idiot can design a speaker, and unfortunately, many do.'
     

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