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  • 15" 2-way Speaker Design

    As part of our forthcoming YouTube video series "Ask A Tech", I'll be using our 15" knock down speaker cabinets. Inspired by Zilch's EconoWave movement, I'm trying to create a 2-way HiFi speaker using PA components with focus on a low-cost, high-value design with maximum dispersion characteristics (constant directivity).

    Another inspiration of this design is to make this an open source project (which, to me, was Zilch's motive). I'd like to create a foundation by which others can build upon.

    The first question I pose is, what cabinet finish? Personally, I prefer the lighter tones of the birch and would love to see the natural waves in the panels to pop. I am, however, open to any and all suggestions for what you would like to see me try. Any help in making the panels have that 3rd dimension where the waves show through is greatly appreciated.

    I will be using the 15" Dayton PA Woofer with the Dayton 12" Waveguide mated to a Selenium D220Ti. The cabinet will be, of course, ported using dual 3" Precision Ports. To make this more of a home HiFi speaker and to keep build time to a minimum, I'm using a set of the Dayton Binding Posts.

    With the parts selected, I can keep my build time low which leaves maximum time for experimentation. One of my goals is to see how the D220Ti responds to the waveguide and how low I can push it, with regards to the crossover, and what modifications to the waveguide have a pronounced usable effect.

    I have drawn up the front and rear panels using Google Sketchup, and plan to make each and every file I generate available to Tech Talk members. Additionally I will be generating files that follow the .frd and .zma format so that anyone can take what I generate, with regards to the installed measurements of the drivers, so that anyone can create a repeatable design using the same drivers tailored to their taste using Jeff Bagby's PCD.

    One of the eye openers, so far, is that the D220Ti has a natural Fs of 2200 Hz unloaded. Once in the waveguide, the Fs dropped to roughly 660 Hz. I did not expect that type of drop as the waveguide, so I thought, didn't seem to really be loading the driver...

    I was thinking of calling this the ZDS-15. Any suggestions?

  • #2
    Re: 15" 2-way Speaker Design

    How about 'Chocks'?
    They're wedge-shaped, and that kinda applies...

    On the D220, I've heard it in decent settings as of late, and I don't think it'll be clean enough for some people, even on that budget. I like the DH200 better, even if it maybe can't play as low.

    15" 2-ways are always hard to get blending right anyway.
    Not that this won't work....
    Later,
    Wolf
    "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
    "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
    "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
    "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

    *InDIYana event website*

    Photobucket pages:
    https://app.photobucket.com/u/wolf_teeth_speaker

    My blog/writeups/thoughts here at PE:
    http://techtalk.parts-express.com/blog.php?u=4102

    Comment


    • #3
      Re: 15" 2-way Speaker Design

      Originally posted by [email protected] View Post
      As part of our forthcoming YouTube video series "Ask A Tech", I'll be using our 15" knock down speaker cabinets. Inspired by Zilch's EconoWave movement, I'm trying to create a 2-way HiFi speaker using PA components with focus on a low-cost, high-value design with maximum dispersion characteristics (constant directivity).

      Another inspiration of this design is to make this an open source project (which, to me, was Zilch's motive). I'd like to create a foundation by which others can build upon.

      The first question I pose is, what cabinet finish? Personally, I prefer the lighter tones of the birch and would love to see the natural waves in the panels to pop. I am, however, open to any and all suggestions for what you would like to see me try. Any help in making the panels have that 3rd dimension where the waves show through is greatly appreciated.

      I will be using the 15" Dayton PA Woofer with the Dayton 12" Waveguide mated to a Selenium D220Ti. The cabinet will be, of course, ported using dual 3" Precision Ports. To make this more of a home HiFi speaker and to keep build time to a minimum, I'm using a set of the Dayton Binding Posts.

      With the parts selected, I can keep my build time low which leaves maximum time for experimentation. One of my goals is to see how the D220Ti responds to the waveguide and how low I can push it, with regards to the crossover, and what modifications to the waveguide have a pronounced usable effect.

      I have drawn up the front and rear panels using Google Sketchup, and plan to make each and every file I generate available to Tech Talk members. Additionally I will be generating files that follow the .frd and .zma format so that anyone can take what I generate, with regards to the installed measurements of the drivers, so that anyone can create a repeatable design using the same drivers tailored to their taste using Jeff Bagby's PCD.

      One of the eye openers, so far, is that the D220Ti has a natural Fs of 2200 Hz unloaded. Once in the waveguide, the Fs dropped to roughly 660 Hz. I did not expect that type of drop as the waveguide, so I thought, didn't seem to really be loading the driver...

      I was thinking of calling this the ZDS-15. Any suggestions?
      In the true spirit of Zilch's efforts, the round waveguide is a step back, as it increases CTC distance quite a bit. 15" woofer already has "issues" reaching 1000Hz with good off axis response, and pushing it further from the tweeter exacerbates the problem.

      I'd opt for the 12" woofer instead for a number of reasons, but if the 15" is desired, a larger rectangular waveguide that allows for a low XO point and tighter arrangement would be beneficial. H6512 comes to mind.
      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


      • #4
        Re: 15" 2-way Speaker Design

        gotta agree with pete on the ctc. this will fun to watch. thanks for sharing.
        i kinda like the idea of the name having a 'Z' in it somwhere.
        " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

        Quote Originally Posted by hongrn. Oct 2014
        Do you realize that being an American is like winning the biggest jackpot ever??

        http://www.midwestaudioclub.com/spot...owell-simpson/
        http://s413.photobucket.com/albums/pp216/arlis/

        Comment


        • #5
          Re: 15" 2-way Speaker Design

          Another vote for the H6512...it just works.

          Just for giggles, why not start with eWave high efficiency variant as your baseline crossover, build it, measure it, and see what you can do to improve it from there?

          http://www.audiokarma.org/forums/att...2&d=1242968714

          Step 1 would be to swap out the coil and cap on the woofer to compensate for the rising response.

          Comment


          • #6
            Re: 15" 2-way Speaker Design

            Why not have a "Voice of the Theater" kind of design, with the waveguide sitting on top of the bass cabinet? A lot of people would be hesitant to cut into a premade cabinet. But building a simple cabinet for the waveguide would be a pretty easy matter
            http://www.google.com/search?q=voice...w=1659&bih=832

            Comment


            • #7
              Re: 15" 2-way Speaker Design

              Originally posted by ligs View Post
              Why not have a "Voice of the Theater" kind of design, with the waveguide sitting on top of the bass cabinet? A lot of people would be hesitant to cut into a premade cabinet. But building a simple cabinet for the waveguide would be a pretty easy matter
              http://www.google.com/search?q=voice...w=1659&bih=832
              That's what Mongo (Ed Lafontaine) did, built a beautiful bass bin topped off by a wood framed waveguide on top.

              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


              • #8
                Re: 15" 2-way Speaker Design

                That's what Mongo (Ed Lafontaine) did, built a beautiful bass bin topped off by a wood framed waveguide on top.

                That's one good looking speaker. Very nice implementation with the horn and the bass bin. There are some niche markets that would go nuts over that speaker.
                Click here for Jeff Bagby's Loudspeaker Design Software

                Comment


                • #9
                  Re: 15" 2-way Speaker Design

                  Awesome! A real eye catcher

                  Comment


                  • #10
                    Re: 15" 2-way Speaker Design

                    The question from the "Ask A Tech" was directed towards use of the 12" waveguide and a D220Ti, so that's the ulterior motive for using it (and it interested me). I also like doing things against the grain :D.

                    I think if I can get the D220Ti crossed low enough, I "should" be able to avoid the CTC issue... but that will be something to deal with.

                    That cabinet that Ed made is sick! Any chance that I can get similar results with Birch?

                    Comment


                    • #11
                      Re: 15" 2-way Speaker Design

                      Originally posted by [email protected] View Post
                      I also like doing things against the grain :D.
                      Me Too....

                      How soon will an Alpha version of the crossover will appear????

                      As soon as I get my tax refund I'll start placing my order...

                      Comment


                      • #12
                        Re: 15" 2-way Speaker Design

                        I posted this on a another thread. It might give you some reason to go with a rectangular horn rather than a round horn.

                        I have a pair of D220It-8 drivers mated up with the H812 horns. Attached is the FR using ARTA. They were tested at about 2m on the bench with no crossovers.

                        My plan was to mate them up with the Dayton PA380'8 woofers but I was waiting for the woofers to go on sale. Now I am wondering about the SPL level difference.

                        I mated the D220Ti-8 with some old ElectroVoice EVM15B 15" woofers and the SPL level was spot on without any need to adjust SPL levels.
                        Attached Files

                        Comment


                        • #13
                          Re: 15" 2-way Speaker Design

                          Attached are pictures of the EVM 15" woofer raw FR in cabinet, the D22Ti in cabinet and the final in cabinet FR with xover. The crossover point was 1200Hz. The cabinets are Community PBL fiberglass which has a built in rectangular horm. As you can see the high end droops a bit as the FR goes higher but they sound great.

                          In the previous post was a picture of the D220Ti in the Dayton rectangular horn on the bench, no cabinet. I will be followin your progress. I think I can make the PA380-8 woofers work well with this driver and horn. Still waiting for the PA380's to go on sale. Winter is gone; weather is warming; it is time to get back in the shop.

                          Mongo's speakers are beautiful, great work.
                          Attached Files

                          Comment


                          • #14
                            Re: 15" 2-way Speaker Design

                            Originally posted by [email protected] View Post
                            The question from the "Ask A Tech" was directed towards use of the 12" waveguide and a D220Ti, so that's the ulterior motive for using it (and it interested me). I also like doing things against the grain :D.

                            I think if I can get the D220Ti crossed low enough, I "should" be able to avoid the CTC issue... but that will be something to deal with.

                            That cabinet that Ed made is sick! Any chance that I can get similar results with Birch?
                            the picture does not do them justice. they simply glowed. doug mentioned to me that he had to turn the volume way down for these. very efficient
                            " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                            Quote Originally Posted by hongrn. Oct 2014
                            Do you realize that being an American is like winning the biggest jackpot ever??

                            http://www.midwestaudioclub.com/spot...owell-simpson/
                            http://s413.photobucket.com/albums/pp216/arlis/

                            Comment


                            • #15
                              Re: 15" 2-way Speaker Design

                              I built the E-wave using a JBL 15" 136A as the woofer. This was for a center channel to match the 4430s that I have as mains.

                              It does a great job.

                              Comment

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