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new project: The Nines

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  • new project: The Nines

    I made these for a friend. The name comes from the number 9 being her number. TM using N140-8 and ND20FB, ported in 10L w/ 1.5 x 6.5" port. PVC port is 6.25" long and inset 1/4" in cabinet with 3/4" roundover flared opening - flare cuts into PVC a little. 13"H x 7.5"W x 10"D 3/4" MDF cabinet w/ 3/4" roundovers on front sides.

    Construction was simple since neither driver requires a recess. The ND20 hole was also made with my Craftsman router jig. Tweeter is only 1/2" deep and so 1/4" or so must be removed from inside for mounting. I temporarily hot-glued the ports in place so I could remove to mount the tweeters, but the screws can be accessed through the port. Single cabinet window brace behind center of woofer - not really a full window brace - curved at front behind woofer.

    I bought those terminals from Meniscus when they had them on special a few months ago for $0.79 each

    Sound is very nice. Female vocals are sweet. Bass is nice, reaches pretty low w/o any boom or mud, highs are nice as always using ND20. I like the bass on the ND140 so much better than that from the HiVi B4N - when I built these I thought maybe it was the 1/2" MDF, but with listening to these I realize it is the B4N. I like the B4N, but a little too much distortion in the bass region. Sound on these does not change much standing up or walking around the room - I like TM's and kinda do not like MTM's for that reason.

    Response does not have port response added in, F3 around 50Hz. If you can make a 20L box, F3 in low 30's can be had

    Crossover is pretty simple. Notches are necessary. Cap on woofer deals with resonance just beyond 10k, LCR deals with 5dB shelf from 1.0 to 2.5kHz. Zobel on tweeter deals with rising response. Woofer inductor will need to be unwound. I can figure out how many winds to unwind the inductor if you need - I started with a 3.5mH since I had bought 10 of them to get a discount. I can send a pair of 0.03uF caps (set of mylar 100V caps) to anyone who wants to build the design for cost of shipping - $1. Woofer cap could be a NPE to save $4. Cap value on LCR not critical, between 17 and 22uF will be fine.

    I'll add some more pics this weekend when the sun returns.






    Brad
    piano black sealing mdf irregular recesses grill technique

  • #2
    Re: new project: The Nines

    Looks nice!
    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: new project: The Nines

      Nice cabinet work and paint job.
      Dave
      http://www.pellegreneacoustics.com/

      Trench Seam Method for MDF
      https://picasaweb.google.com/101632266659473725850

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      • #4
        Re: new project: The Nines

        Those look very nice. Any construction photos?

        Comment


        • #5
          Re: new project: The Nines

          that paint is amazing. please explain how you did this. would love to see the crossover too. its always nice to see how others do it.
          you have a woodburning stove so, we expect year-round from you:D
          Last edited by [email protected]; 06-11-2010, 08:05 AM. Reason: more
          " 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/

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          • #6
            Re: new project: The Nines

            What a nice writeup. Thanks.

            Comment


            • #7
              Re: new project: The Nines

              Very good-looking cabinetry.
              Paul

              Comment


              • #8
                Re: new project: The Nines

                Originally posted by [email protected] View Post
                that paint is amazing. please explain how you did this. would love to see the crossover too. its always nice to see how others do it.
                +1

                Comment


                • #9
                  Re: new project: The Nines

                  Very nice looking finish! I like the flared port, too! I can't imagine how you get any work done with such a tiny compressor...;):D
                  "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy." --Winston Churchill

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                  • #10
                    Re: new project: The Nines

                    Thanks for the write up...those look awesome! You do some really great work. I'm seriously tempted to build a set of these.

                    Comment


                    • #11
                      Re: new project: The Nines

                      Well done Sir, very well done. Sometimes a simple cabinet style with a catchy paint job really makes a grand impression. I like it!

                      WayneW

                      Comment


                      • #12
                        Re: new project: The Nines

                        Originally posted by [email protected] View Post
                        that paint is amazing. please explain how you did this. would love to see the crossover too. its always nice to see how others do it.
                        you have a woodburning stove so, we expect year-round from you:D
                        I seal the MDF with thinned fiberglass resin. I then used a high build automotive primer to flatten the panels a little - not necessary as I applied the paint over the top of the fiberglass last time. I believe that bondo is fiberglass resin with a bunch of some powder added. I use an orbital sander with 320 grit before painting - you will see some sanding scratches, but not all that noticeable and can be removed by finish sanding and polishing. I generally use PPG Delstar for the top coat, but I tried PPG Omni this time. The Omni does not cover as well, but costs about 1/3 as much. The mixing ratios that the manufacturer recommends are way off. I've found that a mix of 8 parts paint, to 8 parts reducer, to 1 part hardener will provide a finish that will lay out flat w/o any orange peel.

                        Thanks for the compliments.

                        Impedance:


                        More pics tomorrow.
                        Brad
                        piano black sealing mdf irregular recesses grill technique

                        Comment


                        • #13
                          Re: new project: The Nines

                          I didn't take any build progress pics, but this baffle that I made to test the driver pairing in my other cabinets w/ replaceable baffles is done the same. Be sure to drill the tweeter mounting holes and screw in the screws before gluing on the baffle.



                          I like how this pic turned out. I did not fine sand or polish the finish since the paint lays out pretty flat and the gloss is never as good.

                          Brad
                          piano black sealing mdf irregular recesses grill technique

                          Comment


                          • #14
                            Re: new project: The Nines

                            The mixing ratios that the manufacturer recommends are way off. I've found that a mix of 8 parts paint, to 8 parts reducer, to 1 part hardener will provide a finish that will lay out flat w/o any orange peel.
                            Just a quick note on this comment, from a painter's POV....
                            Those look great, and I would not presume to tell you otherwise, and they will probably be fine for indoor use. But the manufacturer mixing ratio's are not "off", they are not "recommended" ratios...they are THE ratios, that's how you mix them. If you need to get a flatter finish, you change the hardener, or reducer you are using.
                            If I can't afford it...I don't need it

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                            • #15
                              Re: new project: The Nines

                              FWIW- I never even mount the ND20FB-4 with screws. It has a tapered neck on it, so it can be press-fit and used with a sealant.

                              It's easier for me that way... :rolleyes:
                              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

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