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Compact, Nearfield 3 way thoughts . . .

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  • Compact, Nearfield 3 way thoughts . . .

    I keep trying to come up with a design that can approach the sound of the 1.6 cu ft 12" woofer loaded cabinets with a MT (separate 5" mid with 1" tweeter) cabinet sitting on top and crossed at around 150 ~ 300 Hz - only in a much smaller cabinet/footprint.

    So far all I can come up with is to emulate the Troels and his Bass Module using an 8 " down firing subwoofer driver with face tilted upwards (30*) and out of a rectangular opening in the lower front of the cabinet (~ 1 cu ft or less) with the Mid installed just above that woofer opening and the tweeter mounted above the mid.
    This alignment is in order to maintain the SHORTEST Height of the overall enclosure. I'd rather it be deeper (depth) than taller or wider but keep it under 10" wide, overall and no more than 14" tall.
    If the woofer is vented then the port can go on either the front or back - I am looking for detail and note-changes not just one-note thump.

    If the Woofer is mounted on the bottom at 60*-ish from the MT - how much difference will it make (phase-wise) if crossed at 150 HZ using 2nd order/12db X-over?

    The Troels say that below 150 Hz you need to move air fast with a lot of surface area to make good sounding low-end and from my experience he is right as rain.

    86 db sensitivity isn't going to cut it in an 8" woofer . . . or will it?


    T
    <M___
    \_W__


    I ramble . . . on . . .



  • #2
    Currently building a similar design to these http://www.troelsgravesen.dk/SBA-941.htm for a customer (same drivers).

    He is looking for something with a more classic/retro style in as compact a design as possible. They will find themselves going between his mixing studio and living room as the mood takes him so they had to work in a nearfield situation.

    It'll be the first time I use this woofer but planning on using it a lot more. F3 ~33Hz in 40L (1.4cu ft).

    It's capable of 25hz in 70L (2.4cu ft) design....more on that in the future....

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    • #3
      That linked design looks nice but still a bit too large physically for my application - Good luck with your build.

      Comment


      • #4
        In the background is the Norcal Charlie Laub Peerless Vifa 5" 2 way atop an Anarchy tapped horn. DIYSG used to kit these. Narrow but a bit deep. Good to 25hz. This is a bass management setup with HT amp with subout, separate amp.

        https://www.avsforum.com/threads/ree...-horn.1238398/

        Click image for larger version

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        • #5
          Side firing woofers crossed low are a good option too. You can cross <= 250Hz for this type of application IMO, and a passive crossover with big coils is going to cost a bit.

          Based on responses I don't think folks caught this part: 14" tall, 10" wide, however deep it takes right? That sounds like a new design to me.
          Electronics engineer, woofer enthusiast, and musician.
          Wogg Music
          Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

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          • #6
            ^ Correct, Wogg!

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            • #8
              Guys, thanks for the ideas/links - still on the search/cogitating designs.

              I can make the baffle shorter by tilting the woofer down to where it takes almost half its width in baffle height . . .

              I should probably draw a picture or something.

              Comment


              • djg
                djg commented
                Editing a comment
                Why stop halfway?

                https://www.parts-express.com/Dayton...r-Kit-300-7160

              • Steve Lee
                Steve Lee commented
                Editing a comment
                This ^ has real possibilities - mated with a 2 ~ 3" FR and/or to a 1/2" tweeter installed in the front of the cabinet as low as possible.
                Could be perfect for the shelf above my desk . . . the size is about right too.

            • #9
              For nearfield work, deep-reaching three-ways are problematic from a physics basis, although advances in small sub-woofer technology like Dayton's Epiques help things. The solutions aren't cheap, however. Time and phase alignment of frequencies above 150Hz easily become an issue. You can go back nearly a hundred years when "talkies" came to movie houses and read the engineering Western Electric and others spent on making sound understandable in barn-like "theaters" that might seat a thousand where old "live" Vaudeville and Broadway Houses rarely seated 400 with three balconies, like the old Orpheum built before statehood in Tulsa and converted to a movie house. May West performed live there in 1916 as a teenager, all 4 foot 1 inch of her but you could hear her sing out on Birch Street (3rd Street) clearly!

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              • #10
                Originally posted by wogg View Post
                ...14" tall, 10" wide, however deep it takes right? That sounds like a new design to me.
                What about these?
                https://toidsdiyaudio.com/product/101/

                Comment


                • Steve Lee
                  Steve Lee commented
                  Editing a comment
                  Another possibility, for sure - but I am not so much interested in sub woofer boom than I am in the fullness and effortless sound of a large speaker system in a compact design although without actually hearing the DINAS I cannot discount them.

                  Thanks for the thoughts/contribution - I have recently taken inventory of my speaker driver collection and find that I am WAY behind on building cabinets/cross-overs and need to get up off my *** and utilize the ridiculous levels of available drivers I have accumulated by thinking too much . . .

                  :D

              • #11
                Steve Lee RE: Subwoofer boom

                That's not really a thing unless you're setting up subwoofers incorrectly. Most people do set them up incorrectly, so I know where you're coming from. The DINAS aren't really a subwoofer system either, just an option where a full range speaker is used to reach low enough to mate to a woofer that goes really low but can't reach to a traditional tweeter. Personally I'm hesitant to use that in a larger room and would lean toward near field for such a design, but I'm not sure that's a rational position. I just prefer small diameter domes for highs, I like the sparkle.
                Electronics engineer, woofer enthusiast, and musician.
                Wogg Music
                Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

                Comment

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