Announcement

Collapse
No announcement yet.

Examples of MMTMM?? Need good vertical directivity.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Examples of MMTMM?? Need good vertical directivity.

    My new HT area doesn't have much need for controlled directivity in the horizontal direction (very wide), unlike my last room. Now I only need vertical directivity. Think MMTMM. So I'd like to study the concept. Any examples out there?

    Also need a tweeter that is directional vertically down to 1500hz or less. My original plan was SEOS 12, but there is another wrench thrown into the mix. I now have to make these in wall. So I only have about 4" depth to work with. Thinking tall ribbon/planer, but to fragile and expensive. I need a short and shallow waveguide. But then it won't control directivity low. :rolleyes:

    What to do.
    https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

  • #2
    Re: Examples of MMTMM?? Need good vertical directivity.

    Originally posted by ryanbouma View Post
    My new HT area doesn't have much need for controlled directivity in the horizontal direction (very wide), unlike my last room. Now I only need vertical directivity. Think MMTMM.
    Vertical dispersion with four midbasses will be about 1/4 that of one, but to get pattern control with the highs you'll need at least two tweeters, if not four. Think line array, a line of midbasses next to a line of tweeters.
    www.billfitzmaurice.com
    www.billfitzmaurice.info/forum

    Comment


    • #3
      Re: Examples of MMTMM?? Need good vertical directivity.

      I don't want to array the tweeters, because I don't understand true line arrays and because at high frequencies I don't believe in them. Maybe I'm wrong. But if I can get some vertical control from a waveguide that would work for me... As you can imagine, finding a waveguide that'll do it is tough unless it's large. I suppose I could just allow it to flare a little bit at the bottom of its pass band.

      I'll shade the top and bottom woofers to keep a linear power response. Like this, but vertically aligned: http://www.diysoundgroup.com/forum/index.php?topic=11.0

      Thinking of using the Aura NS6 for the woofers.
      https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

      Comment


      • #4
        Re: Examples of MMTMM?? Need good vertical directivity.

        A true ribbon exhibits excellent vertical directivity......but they don't go as low as you require.....which I'm not sure if you use a small enough midwoofer is actually a real concern. Take a look at Zaphs Za5.5 for some design guidelines.

        Comment


        • #5
          Re: Examples of MMTMM?? Need good vertical directivity.

          Originally posted by ryanbouma View Post
          My new HT area doesn't have much need for controlled directivity in the horizontal direction (very wide), unlike my last room. Now I only need vertical directivity. Think MMTMM. So I'd like to study the concept. Any examples out there?

          Also need a tweeter that is directional vertically down to 1500hz or less. My original plan was SEOS 12, but there is another wrench thrown into the mix. I now have to make these in wall. So I only have about 4" depth to work with. Thinking tall ribbon/planer, but to fragile and expensive. I need a short and shallow waveguide. But then it won't control directivity low. :rolleyes:

          What to do.
          Why do you think you need vertical directivity from the tweeter, or for that matter, from the speaker?

          Comment


          • #6
            Re: Examples of MMTMM?? Need good vertical directivity.

            What's the tweeter budget? Would $60.00 each break the bank? I've done a MT aura ns6/RT2II that has a narrow sweet spot for vertical directionality. What I don't know is if you went MTM and had less padding if the tweeter could still handle the lower crossover point I used to pair it up with the NS6.

            Take it easy
            Jay
            "I like Brewski's threads, they always end up being hybrid beer/speaker threads based on the name of his newest creation." - Greywarden

            Breakfast Stout - HiVi RT2 II/Aurasound NS6
            Imperial Russian Stout - Vifa DX25/Fountek FW146/(2) Fountek FW168s - Built by Fastbike
            Ruination 2.5 way - Vifa DX25/Fountek FW168
            Levitation TM
            - Vifa BC25SG15/Fountek FW168

            Comment


            • #7
              Re: Examples of MMTMM?? Need good vertical directivity.

              I woudl not do a ribbon or planar due to power handling demands of a home theater and the requirement to cross too low, if I remember Jay were't you ar like 2.5-2.7K with the RTII? He is looking for almost an octave lower. I would recommend the D2604/833000or its lil' brudder'... These guys were made for this. The RS28 is always another low-crosser option. If you wanted to throw a lot of money at it, there are some Seas, Scans, and I believe others that are $100+ that will do it well, too.

              Speaking for the D2604, It is crossed with a shallow knee at 1200Hz on the Fatbellies and hits a brickwall at 800, and does so with extremely low distortion. I'ts in the crushmans too, 3BW at 1700 with no notch filters, straight forward x-over with just padding and it is effortless and dynamic. It truly is a beast of a tweeter.
              .

              Comment


              • #8
                Re: Examples of MMTMM?? Need good vertical directivity.

                It's 4th order bessel at 2300 Hz where I'm crossing it with less padding though it might not be able to handle that. I was just thinking narrow vertical window with ns6 sounds pretty familiar.
                "I like Brewski's threads, they always end up being hybrid beer/speaker threads based on the name of his newest creation." - Greywarden

                Breakfast Stout - HiVi RT2 II/Aurasound NS6
                Imperial Russian Stout - Vifa DX25/Fountek FW146/(2) Fountek FW168s - Built by Fastbike
                Ruination 2.5 way - Vifa DX25/Fountek FW168
                Levitation TM
                - Vifa BC25SG15/Fountek FW168

                Comment


                • #9
                  Re: Examples of MMTMM?? Need good vertical directivity.

                  Brewski, I'll do my own design as I'm in wall. Thanks though.

                  Rpb. I forgot to mention I'm now 10' away with ceiling tile and laminat flooring. And, because I can.

                  Mayhem. A WMTMW is looking more and more right for the job. Then a ribbon would work.

                  Thanks for the suggestion Mike.

                  Keep em coming guys. Any one use the ns525? I could do 8 per side of those in my budget.
                  https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

                  Comment


                  • #10
                    Re: Examples of MMTMM?? Need good vertical directivity.

                    Why not build a pair of on wall speakers with the SEOS 12? I believe the horn and CD are less than 6" deep.
                    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                    http://www.diy-ny.com/

                    Comment


                    • #11
                      Re: Examples of MMTMM?? Need good vertical directivity.

                      It may fit with a built out baffle, but the wall is 4" deep. 2 x 4 construction, so actually 3.5" plus drywall. I still might though.
                      https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

                      Comment


                      • #12
                        Re: Examples of MMTMM?? Need good vertical directivity.

                        These might be of interest.
                        http://www.parts-express.com/pe/show...number=299-278

                        Or these.
                        http://www.parts-express.com/pe/show...umber=264-1062

                        Comment


                        • #13
                          Re: Examples of MMTMM?? Need good vertical directivity.

                          Originally posted by ryanbouma View Post
                          .

                          Mayhem. A WMTMW is looking more and more right for the job.
                          A ribbon would also work for an MMTMM if a 2.5 way topology is used in the crossover but would agree that the WMTMW would be the more ideal option.

                          Comment


                          • #14
                            Re: Examples of MMTMM?? Need good vertical directivity.

                            Is the gluing really that sloppy on those Peerless 832444 drivers as seen in the picture?

                            No matter where you go, there you are.
                            Website

                            Comment


                            • #15
                              Re: Examples of MMTMM?? Need good vertical directivity.

                              B&G Neo8PDR?
                              "It is only Scrooge McDuck and others with a personality disorder who have money as their goal"

                              Comment

                              Working...
                              X