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A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

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  • A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

    Trade-offs, trade-offs, trade-offs. As I posted earlier, I am working on as yet unnamed AC130/F1-OWII MTM speakers in an MLTL arrangement. I'd like to get the table saw spinning today, yet I'm a bit stuck on the many tradeoffs on the alignment decision.

    The upper graph below is just about optimized for flat and maximal f3 extension, but results in a foot print that is about 8" X 16", a bit larger than I'd like.

    The lower graph is an alternative with a smaller footprint, and an alignment that provides less extension with a bit of a boost in the 50-100 range - rather like Jeff B's Continuums use to flesh out the low end - though the Continuum boost may be a bit higher in frequency.

    Parameters such as excursion and port velocity are acceptable in either case.

    Which would you expect to provide more satisfying listening and why?


  • #2
    Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

    I would prefer the second one, Maynard. I've been doing some thinking on this topic, and I am wondering if I like a high"Q" bass alignment not for the extra bump it gives me, but because it might help to alleviate some of the loss to floor bounce?

    Or maybe I am a basshead beyond hope.
    Don't listen to me - I have not sold any $150,000 speakers.

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    • #3
      Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

      I think the smaller box may end up sounding like a much bigger box....in a good way. It looks like the rise starts low enough to keep them from sounding bloated. And the difference in F10 looks to be only a few hertz. Wouldn't the biggest factor be how you stuff them?
      Co-conspirator in the development of the "CR Gnarly Fidelity Reduction Unit" - Registered Trademark, Patent Pending.

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      • #4
        Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

        Originally posted by tom_s View Post
        I think the smaller box may end up sounding like a much bigger box....in a good way. It looks like the rise starts low enough to keep them from sounding bloated. And the difference in F10 looks to be only a few hertz. Wouldn't the biggest factor be how you stuff them?
        The stuffing is pretty optimized in either case. Many factors interact. I also must keep the ripple at 700-800 tamed - so 1# / cu. ft. is used in the top 1/3rd or so of the line.

        The main ?? of the post is more about experience or philosophy regarding the maximally flat and extended vs. a bit of a boost 50-100.

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        • #5
          Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

          It's really difficult to make a judgment because other than a few Hz difference in F3, the two responses aren't all that different. Without hearing either beforehand, much less in an A/B comparison, I'm guessing the second, smaller box will sound better, probably a bit fuller in bass.
          Paul

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          • #6
            Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

            Originally posted by tom_s View Post
            I think the smaller box may end up sounding like a much bigger box....in a good way. It looks like the rise starts low enough to keep them from sounding bloated.
            +1

            Chris
            Chris

            Goofing around since 2000.

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            • #7
              Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

              #2.

              Since after the knee remains relitivly soft for a "high q", it seems the motors on those lil guys will have a fair amount of control. You may want to meet the alignmts 1/2 way. I feel the first would lack impact given the driver size, even border on being tubby sounding.
              .

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              • #8
                Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

                I'm late to the party as usual, and no doubt you've made your decision already.

                I wouldn't be too worried about using the smaller design, as a little 'extra' bass never hurt a 5" design any. I suspect the bass will sound fuller overall, and only on material with very deep bass will you notice the relative differences.

                C
                Curt's Speaker Design Works

                "It is the mark of an educated mind to be able to entertain a thought without accepting it."
                - Aristotle

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                • #9
                  Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

                  Actually, you are not late to the party. The mdf shelving I'll be using remains in the car. I spent the day yesterday gathering materials (where does the MDF go?)

                  Also, I cut the "positive" patterns for the truncated AC130/F1 and for the OWII, which I truncated to achieve closer C-to-C spacing. These exactly match the shape of the flanges of the speakers - which cannot be detached. Then I can use a router guide insert with a 1/4" upcut bit to cut a "negative" pattern larger than the flange for each driver. The negative pattern will be used with another router guide insert to cut the actual flange recess at the correct shape and depth for each driver. At least I think so - will have to lay it out further. Then, I'll cut the cutouts.

                  Regarding the bass alignment, I'll be using #2, the smaller footprint with a bit of bass boost. It is the best compromise, and there is always a compromise. There will be some latitude to play with stuffing and port length.

                  Last edited by maynardg; 12-05-2010, 11:32 AM.

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                  • #10
                    Re: A Quiz - Dual AC130 MLTL Alignment Options - Paul, Jeff, Curt - anyone???

                    Originally posted by maynardg View Post
                    Actually, you are not late to the party. The mdf shelving I'll be using remains in the car. I spent the day yesterday gathering materials (where does the MDF go?)

                    Also, I cut the "positive" patterns for the truncated AC130/F1 and for the OWII, which I truncated to achieve closer C-to-C spacing. These exactly match the shape of the flanges of the speakers - which cannot be detached. Then I can use a router guide insert with a 1/4" upcut bit to cut a "negative" pattern larger than the flange for each driver. The negative pattern will be used with another router guide insert to cut the actual flange recess at the correct shape and depth for each driver. At least I think so - will have to lay it out further. Then, I'll cut the cutouts.

                    Regarding the bass alignment, I'll be using #2, the smaller footprint with a bit of bass boost. It is the best compromise, and there is always a compromise. There will be some latitude to play with stuffing and port length.

                    Thanks for documenting the pattern making for odd-shaped drivers. It helps the cabinet-inept like myself.
                    .

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