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  • What the, no crossover?!?!?


    So I have an old set of MTX AAL212 towers that I bought at a garage sale for $150. I'm living in dorms and can't go without my speakers anymore, but they're just too bloody big. I've decided rather than building some new, smaller, DIY speakers, that I should save the money and just build some smaller boxes for my ol' garage sale find. I cracked them open the other night and noticed there wasn't much of a crossover... just a couple capacitors. One between the woofers and the mid, and another between the mid and tweeter. I was wondering if building a crossover would make them sound better or if I should just leave it? Here are the speakers specs from the mtx archives.

    12" 3-Way
    Dual 12"Fiber Foam Surround
    2" Voice Coil
    5" Mid-bass
    2"x6" Horn-Loaded Quartz
    38Hz-22kHz
    93dB
    8 Ohm
    300 Watts RMS/
    600 Watts Total
    38-7/8"
    15-3/16"
    15-5/8"

    Any advice or suggestions would be great.
    Thanks, Jeff

  • #2
    Re: What the, no crossover?!?!?


    > So I have an old set of MTX AAL212 towers
    > that I bought at a garage sale for $150. I'm
    > living in dorms and can't go without my
    > speakers anymore, but they're just too
    > bloody big. I've decided rather than
    > building some new, smaller, DIY speakers,
    > that I should save the money and just build
    > some smaller boxes for my ol' garage sale
    > find. I cracked them open the other night
    > and noticed there wasn't much of a
    > crossover... just a couple capacitors. One
    > between the woofers and the mid, and another
    > between the mid and tweeter. I was wondering
    > if building a crossover would make them
    > sound better or if I should just leave it?
    > Here are the speakers specs from the mtx
    > archives.

    > 12" 3-Way
    > Dual 12"Fiber Foam Surround
    > 2" Voice Coil
    > 5" Mid-bass
    > 2"x6" Horn-Loaded Quartz
    > 38Hz-22kHz
    > 93dB
    > 8 Ohm
    > 300 Watts RMS/
    > 600 Watts Total
    > 38-7/8"
    > 15-3/16"
    > 15-5/8"

    > Any advice or suggestions would be great.
    > Thanks, Jeff

    Without measurements, there's no way to determine what kind of XO mods, if any, can be made to improve the sound.

    The XO uses the woofer's and mid's natural roll-off to make the XO work to some extent. I wouldn't mess with it. Get an equalizer and adjust for your taste. Then, build some nice, proven designs, when budget permits.
    R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
    Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

    95% of Climate Models Agree: The Observations Must be Wrong
    "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

    Comment


    • #3
      Re: More than a few "old school" speaks...


      ...were created with minimal crossovers... And with some designs, like an Eminence Beta 8 and a piezo, well, it ain't gonna be great, but just wire it up, and you have loud.

      One of my favorite sounding speakers is the old EPI-100... 8" woof rolling off smoothly, with a 10 mike cap before tweet... Or was it .10? I dismember. That was _it_.

      If you choose drivers well, _or have them built to your specs_, you can get away with stuff like that.


      Comment


      • #4
        Re: More than a few "old school" speaks...


        > ...were created with minimal crossovers...
        > And with some designs, like an Eminence Beta
        > 8 and a piezo, well, it ain't gonna be
        > great, but just wire it up, and you have
        > loud.

        > One of my favorite sounding speakers is the
        > old EPI-100... 8" woof rolling off
        > smoothly, with a 10 mike cap before tweet...
        > Or was it .10? I dismember. That was _it_.

        > If you choose drivers well, _or have them
        > built to your specs_, you can get away with
        > stuff like that.

        St. Louis DIY???????
        R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
        Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

        95% of Climate Models Agree: The Observations Must be Wrong
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

        Comment


        • #5
          Re: More than a few "old school" speaks...


          > If you choose drivers well, _or have them
          > built to your specs_, you can get away with
          > stuff like that.

          Certainly. That's not to say it will sound good. The JVC three way I am deconstructing also has just two caps, one for mid highpass and one for tweeter high pass. That's enough to protect the drivers, stop them from farting, but not to really filter the drivers and make them play only their ideal ranges.

          Comment


          • #6
            Re: St. Louis DIY


            Actually, it's looking to be more of a halloween party... Jen's almost back on her feet, and I _really_ have to clear out work area in the garage.


            Comment


            • #7
              Re: What the, no crossover?!?!?


              > So I have an old set of MTX AAL212 towers
              > that I bought at a garage sale for $150. I'm
              > living in dorms and can't go without my
              > speakers anymore, but they're just too
              > bloody big. I've decided rather than
              > building some new, smaller, DIY speakers,
              > that I should save the money and just build
              > some smaller boxes for my ol' garage sale
              > find. I cracked them open the other night
              > and noticed there wasn't much of a
              > crossover... just a couple capacitors. One
              > between the woofers and the mid, and another
              > between the mid and tweeter. I was wondering
              > if building a crossover would make them
              > sound better or if I should just leave it?
              > Here are the speakers specs from the mtx
              > archives.

              > 12" 3-Way
              > Dual 12"Fiber Foam Surround
              > 2" Voice Coil
              > 5" Mid-bass
              > 2"x6" Horn-Loaded Quartz
              > 38Hz-22kHz
              > 93dB
              > 8 Ohm
              > 300 Watts RMS/
              > 600 Watts Total
              > 38-7/8"
              > 15-3/16"
              > 15-5/8"

              > Any advice or suggestions would be great.
              > Thanks, Jeff

              A pair of BR1's and a 10" sub would be a drastic improvement over anything you could possibly do with those. Chances are the boxes that are too bloody big are actually too small for optimum bass. Making them smaller sure isn't the way to go. If you left the crossover alone and just made smaller boxes, whatever bass you had will be gone, and you'd be stuck with a harsh midrange and top end. If you built an optimum crossover, it would improve, but only to a point - there's only so much you can do with cheap drivers. You'd end up replacing the mid and tweet - and you'd still have no bass if the box was made smaller.

              Comment


              • #8
                Re: What the, no crossover?!?!?


                Remember you can also use creative placement. One of the dorms I was in had about 12' between a pair of bookshelves that faced each other... So we took a 2x12, about 13' long, and set it in there on the top shelf... Instant extra mondo shelf for speakers, stereo, etc. Yeah, it ain't gonna be optimal, but hey... Another opportunity would be pipes below the ceiling, etc...

                Use what you have for a while, put a sign on a campus bulletin board with 'em for sale for $150, and when you unload 'em, do some smaller speaks and a sub...

                > So I have an old set of MTX AAL212 towers
                > that I bought at a garage sale for $150. I'm
                > living in dorms and can't go without my
                > speakers anymore, but they're just too
                > bloody big. I've decided rather than
                > building some new, smaller, DIY speakers,
                > that I should save the money and just build
                > some smaller boxes for my ol' garage sale
                > find. I cracked them open the other night
                > and noticed there wasn't much of a
                > crossover... just a couple capacitors. One
                > between the woofers and the mid, and another
                > between the mid and tweeter. I was wondering
                > if building a crossover would make them
                > sound better or if I should just leave it?
                > Here are the speakers specs from the mtx
                > archives.

                > 12" 3-Way
                > Dual 12"Fiber Foam Surround
                > 2" Voice Coil
                > 5" Mid-bass
                > 2"x6" Horn-Loaded Quartz
                > 38Hz-22kHz
                > 93dB
                > 8 Ohm
                > 300 Watts RMS/
                > 600 Watts Total
                > 38-7/8"
                > 15-3/16"
                > 15-5/8"

                > Any advice or suggestions would be great.
                > Thanks, Jeff

                Comment


                • #9
                  Everyone knows I'm no measurement freak, but


                  I'd really like to see some raw measurements of these woofers to see just how smooth they really roll off naturally.

                  Comment


                  • #10
                    Re: What the, no crossover?!?!?


                    > 12" 3-Way Dual 12 Fiber Foam Surround
                    > 5" Mid-bass
                    > 2"x6" Horn-Loaded Quartz(piezo)
                    > 38Hz-22kHz
                    > 93dB

                    Dual 12's and it's only 93db!! WTF. Oh.. the MTX logo says it all. Crappy car audio drivers stuffed into a pro looking PA box. A single Delta 12LF and DH200E will soooo blow these away!!!Been there, done that. So if you're on a no $$ budget, pull the 4 MTX 12's and pawn them off on some car audio guy. Pick up a pair of delta 12lf and either build new cabs bringing along the mid and piezo from the other cabs, or go with the DH200. Even with a minimal crossover these will rock the dorm room with as little as 100w.
                    Paul O

                    Comment


                    • #11
                      Re: What the, no crossover?!?!?


                      About 12 years ago I bought a pair of MTX 4 ways with the 15" driver( I still have them) and was really disapointed when I blew one of the 15'S, I opened it up expecting to find a crossover and all that was there was a couple of litic caps,They came with a ten year warrantee and they honored it with no problem. I was also bummed when I found that the advertized "seperate chambers for each driver" turned out to be only sealed back drivers.

                      I thought they sounded awesome until I built my own,now I cant listen to them,

                      A.H.
                      http://smg.photobucket.com/albums/v655/aaronhero/
                      http://groups.msn.com/aaronsspeakers/pictures
                      [email protected]

                      Comment


                      • #12
                        Re: What the, no crossover?!?!?


                        > About 12 years ago I bought a pair of MTX 4
                        > ways with the 15" driver( I still have
                        > them) and was really disapointed when I blew
                        > one of the 15'S, I opened it up expecting to
                        > find a crossover and all that was there was
                        > a couple of litic caps,They came with a ten
                        > year warrantee and they honored it with no
                        > problem. I was also bummed when I found that
                        > the advertized "seperate chambers for
                        > each driver" turned out to be only
                        > sealed back drivers.

                        > I thought they sounded awesome until I built
                        > my own,now I cant listen to them,

                        > A.H.

                        Yup. "Sealed back midranges" and first order high pass. Funny how it starts rolling off but comes back with a vengeance around resonance - which is not too awfully far away from the "crossover point".

                        Comment

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