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Apollo MTM Passive Radiator Version

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  • Apollo MTM Passive Radiator Version

    Went with passive radiator design utilizing DSA270-PR (one for each woofer). No measurements yet. Will be posting when I take them.. They sound pretty good though. Spent the last couple of days in the shop burning them in on quite a bit of material form Tidal.

    Took my first swing @ wood veneer as well. Not too bad.

    Thought I would post a few pics.

    BSME
    Kannapolis NC

  • #2
    Nice job, nice workshop.

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    • #3
      As promised, here is a measurement overlay of both speakers. Looks pretty smooth with good BSC. Not sure what is causing the -4db dip @ 13000. Could be a measurement anomaly or the fact that I changed the front baffle size slightly. Either way, it doesnt seem audible to my 60 year old ears. They sound really good. Also, this is the first time I have used Omnimic so not sure I got it exactly right.

      Click image for larger version  Name:	APOLLO 1-2.PNG Views:	1 Size:	323.9 KB ID:	1413901

      Click image for larger version  Name:	measurement.jpg Views:	1 Size:	366.2 KB ID:	1413902
      BSME
      Kannapolis NC

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      • #4
        Very nice job - looks good and (by your measurement) should sound very good. The dip is more than likely the tweeter diffraction on the edge of the cabinet and will probably smooth out some off-axis, 10-20-degrees. As you mentioned - most would not be able to hear it, without really good hearing.
        Paul

        The "SB's" build page
        http://techtalk.parts-express.com/sh...-4-(pic-heavy)

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        • #5
          How is the perceived bass?

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          • #6
            Originally posted by westrock2000 View Post
            How is the perceived bass?
            Bass is strong. The WinISD model looked good with 90g added to each PR. I am still doing some tuning but so far I have gone to 120g per. That made the bass perception a bit more defined and a bit deeper but I need to do some more listening and breaking in. I also changed from my bench amp to one of my listening amps and it cleaned it up more. I certainly have a lot to work with. There is no lack of bass at all. I am going to check the tuning with measurements this weekend if I have time and if not I will surely take some soon. I constructed the boxes out of 1" mdf and they are fully lined with 3 layer sonic barrier so they are fairly dead. I haven't done anything with stuffing yet but I have confidence I can work out the bass to sound like I want. To my ears the bass needs a bit more definition @ high volume. They do not sound strained. They just need a little more cone control high output levels.

            Matthew
            BSME
            Kannapolis NC

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            • #7
              The interior definitely needs some stuffing. Standing waves will form and impinge on the cones, so some centrally located absorptive material is essential. If you can wedge a chunk of OC703 near the center of the enclosure it will do a lot to clear up the sound.
              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.

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              • #8
                Hey Harvylogan,

                Good work done by you .This speaker looking very nice. Well Done!

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