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Faux Pas

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  • Faux Pas

    Heresy some might say, but taller and slimmer is the plan (tower version). On-the-cheap with drivers I've slowly acquired over the years to dabble with due to being interested in doing such a build... Waiting for my skill and research to mature enough. I'll call them Faux Pas.

    Tweeter is a P-audio pht-409. A lookalike to those in most of the gen 3 Klipsch heritage line. I got a couple pairs to mess with. The stock diaphragms are phenolic, but due to an incident with a soldering iron.., I decided to try out titanium diaphragms in this pair. If i remember right a pair went for ~$32 on "the auction site". The diaphragms were probably more than that.. oops

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    Midrange CD is from an MCM 53-1240 (discontinued, though I suspect is the same as the 53-1245 with a different horn). Titanium 1.75" Diaphragm. The horn from the 53-1240 looked the part, but had some issues and I found the Dayton H812/Celestion H1-9040P seemed to pair well for a $40 horn/CD combo (nowadays prices).

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    Woofer is tentatively an MCM 55-2952. Not so sure this will stay. For the price ($22 currently) it is hard to expect much. I have used these in a small sealed 2-way, but pulled em to take that project in a different direction because I realized I was being a moron. Interested to see what they do in a larger vented enclosure with less bandwidth to contend with.

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    My first attempt at a 3-way.. may crash and burn. We'll see how it goes.​
    My hopes for these are to satisfy the heavy metal itch.. That my 2-way builds have mostly lacked.
    I'm certainly not good at this. Just stubborn enough to keep going.

  • #2
    Keep us posted - I am doing something very similar right now.


    • #3
      Some extra pics and ramblings since I bumped up to the 5 attachment limit..

      The first thing I noticed comparing to the stock vs titanium diaphragm was the much flatter impedance on the titaniums. Which, initially struck me as possibly being nicer to work with for the higher xo of a 3-way? Maybe just wishful thinking. Because, along with that, came a more pronounced downward slope in the response.

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      The tweeter response posted was surface mounted on baffle. Planning to flush mount this time.. kinda, mostly
      The mid horn response was measured unmounted/free air. Maybe the baffle will bolster the bottom end slightly?

      If anyone cares what the front of the woofers look like.

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      A bit of a personal tradition is to do my digital baffle mockups in ms-paint.. I even got fancy this time and went two tone and added a base.
      It shows the basic premise of how I plan to use the plywood edge to cap the sides of the mid horn recess and top of tweeter recess. Making for a baffle width of ~14"
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      I'm certainly not good at this. Just stubborn enough to keep going.


      • #4
        On to the cabs,

        Being lazy and cheap I wanted to come up with a tower that only took a single 4x8 sheet for the pair. I already have simple plans that I came up with for two 13"x18"x11.75" boxes out of a single 4x4' piece. So I doubled it and massaged the numbers, Ending up with 14"x36"x11.25". And since there are only two cabs instead of four, There are four extra pieces that would otherwise be tops and bottoms to use as braces instead.

        I also really prefer working with plywood instead of MDF. I found some South American Sande wood ply for $60/sheet.

        However, I ended up screwing up and started cutting the sides for height when I meant to do the front/back, So the cabs will be ~34.5" tall instead of 36".. But that isn't a huge deal. I'll add a base to it like I showed in my ms-paint work. I also messed up when cutting some of the inner brace pieces and cut one too narrow, so I cut the other to match then adjusted to cut #3&4 correctly. That's what I get for working on projects after being strung out from a rough day at work and a couple beers in me.

        Free-handing the router for recesses is always a very stressful endeavor. I haven't gotten into router jigs yet. This time I tried using the table saw to define the straight lines of the horn recesses. This gives me a little safety net when using the router to get out the rest of the bulk.

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        However, since the sides and top will butt right up to the horns i need to get some material out with the router before assembly. There were a couple slips (not in the photo) but I'm not too worried about that. All part of the process.

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        Gluing up is a slow process. I've only got so many clamps. I added some scraps to give a little extra meat for the mid horn mounting screws.. There will be a good amount of torque with the big CD hanging 8" off the end.

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        There is one thing that sucks about plywood compared to MDF... it is rarely flat. That hasn't caused too much issue for me up until now, it sucks for towers because the bow really adds up on the length. You start needing to keep it in mind each part you are gluing on and figuring out how to straighten it all out by the end. My kitchen dining set has bench made of 1.5" butcher block. I've been clamping it down to that and makes a decent reference for flatness with the square.
        Last edited by DrewsBrews; 09-15-2022, 10:20 PM.
        I'm certainly not good at this. Just stubborn enough to keep going.


        • #5
          Looks good so far - you might want to consider supporting the CD somehow as once you drop or shock-load this cabinet it will likely break your horn - just a thought (I am doing this with my current project).


          • #6
            I understand. That was one concern about the horn that came with the CD. The plastic was rather thin and I seem to remember reviews saying it would break in shipping with the CD attached. Though, all the ones I ordered arrived undamaged. The H1-9040P are nice and thick and have thick reinforcement ribs. Also since the horn is about as tall as it is deep I think it can withstand torque better than a narrower horn. I'm confident it can handle enough of a drop that I'd be just as concerned for other parts in the same situation.

            The speaker in my avatar pic I used an H812 (pretty much identical to H1-9040P) with Selenium D220TI that was threaded, necessitating a thread adapter, making it even deeper. I wasn't too worried about it. Though I don't mistreat them.
            I'm certainly not good at this. Just stubborn enough to keep going.


            • #7
              A few suggestions...Regarding MS Paint, Sketchup is easy to learn (there are some better/more powerful programs if you ever get into 3D printing) and can really help if you start getting into complicated cabinets. I have made a curved cabinet and was able to easily figure out the net volume in Sketchup without a lot of manual calculations. I built a trapezoid cabinet and mocked it up in Sketchup and got all of my angles from there without having do do any manual calculations.

              I recently also tried choosing my cabinet dimensions such that I can maximize the use of 1 sheet of wood. This free site is pretty awesome --->


              • DrewsBrews
                DrewsBrews commented
                Editing a comment
                Yeah I bet I'd have to do that if I ever decide to do anything more fancy than flat 6-sides.

            • #8
              Got tops and bottoms on. Going to probably glue in a brace to one side before I put the sides on.

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              I'm certainly not good at this. Just stubborn enough to keep going.


              • #9
                Going back and forth deciding about rear or front port. Will be 4"dia x 4"long.

                I'm thinking rear because it can be stuffed if needed and remain out of sight. I may limit BSC to maintain efficiency so a bit of a bottom end boost might not be too bad. These sort of designs aren't necessarily aiming for highest linearity. But boomy can get annoying. My living room doesn't seem so sensitive to bass, but these may end up at my father's apartment. His living room is super bass happy so any port will probably be stuffed in that case.
                I'm certainly not good at this. Just stubborn enough to keep going.


                • #10
                  Thanks for doing a real time build thread. I think people really enjoy following a project. I do.


                  • DrewsBrews
                    DrewsBrews commented
                    Editing a comment
                    Thanks, often I feel like I'm not doing things many others would find particularly interesting. Just kinda forcing myself to get out there more.

                • #11
                  Friday night I got the side brace glued to one of the sides and glued that side to the box. Then Saturday I glued the other side on. This evening I pulled out the flush bit on the router and went to town. There was one corner that tried to tear out and fan folded some of the plys. Fortunately it was on a bottom rear corner and nothing came completely off. Pulled the pieces back and squirted some glue in. Clamped for an hour. That should take care of that.

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                  Starting to come time for many decisions to be made..

                  I'm waffling yet again on the port. Now I'm thinking front port. That spurred me onto an idea for the grill.

                  I initially I was going to finish the plywood as-is (and maybe paint the front baffle), and that is still an option I may ultimately go in. However, after I saw djg's build I found myself at the hardware store today putting a roll of paper backed veneer in the cart.
                  Unfortunately, all of the sudden, weldwood quart cans seem to be unobtanium locally (checked a few stores). And I don't want to wait for it to be shipped in. So either I buy a whole gallon, or I look into other application methods. I've heard of a dried titebond iron on method, but that is about all I know. Does anyone know many details such as can that be used for paper backed veneer? How thick to apply the titebond? Can it be titebond II/III or original required?

                  I picked up some 1x2" for the base. Probably going to make it a little smaller than the box dimensions for the pedestal look and paint it black.

                  And lastly I grabbed a chunk of plywood I have lying around and cut a hole to mount the woofer as a testing baffle. Unfortunately looks to be only 3/8" ply. I'll scrounge for a few 2x4s or something to clamp on it to give some rigidity while running the sweeps.
                  I'm certainly not good at this. Just stubborn enough to keep going.


                  • djg
                    djg commented
                    Editing a comment
                    Actually they look kind of cool with the exposed plywood edges. Another approach is iron on edge tape veneer to cover the exposed endgrain. I tried titebond once and wasn't very successful. Many people swear by it. Also available is another heat activated adhesive. You can easily research all this.

                  • DrewsBrews
                    DrewsBrews commented
                    Editing a comment
                    Unfortunately there are some burn marks from the router on the edges that I doubt will sand all the way out. I was being a bit more cautious around the horn recess area and lingered a little too long in some spots. At one point I had an in-line speed controller I'd use but it bit the dust years ago and have just been getting by without it since.

                • #12
                  Got some nearfield measurements on the woofer. I'm quite tickled by the result for my intended purpose at least. Unless you guys see something I don't?

                  1/12 smoothing applied

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                  I'm certainly not good at this. Just stubborn enough to keep going.


                  • #13


                    • #14
                      More router and saw work. Starting to get a better idea what it will look like.

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                      I'm certainly not good at this. Just stubborn enough to keep going.


                      • #15
                        Iron on edge veneer tape would look like this.

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