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  • transcenD

    This project has been in the works for a long time. I work slow to begin with and don't have much free time to dedicate to hands on building, but I finally got these done and am happy with the outcome. The design is a relatively small (medium size perhaps) three-way vented floor standing speaker. It uses a Fountek Neocd1.0 ribbon, ScanSpeak 10F/4424G mid, and Dayton RS225-8. The capital "D" on the end of the name is intentional, to pay a personal tribute to what is still one of my favorite commercial speakers I've owned, the EPI A500 (D is roman numeral for 500). They really at this point only have in common with the A500 the fact that they are three-way floorstander. The initial build had cabinet colors that mimic the A500, but the baffle color was changed to black at request for something different (WAF). I will post a pic with the original baffle color.

    Initially these were going to use a HiVi M8N and Vifa TC9FD18. My inability to get the TC9 and low-mounted M8N to play nice together (sensitivity of a single TC9 was a little too low), forced me to switch drivers. I (am probably the only person here who..) have never used a RS woofer before and was itchy to try one, so I ended up switching woofers in addition to the mid. I already had the baffles done, and finding a driver to do what I needed in the mid and fit the hole was actually quite a challenge, but the 10F worked well. I actually ordered another TC9 pair (because they are probably the biggest bargain in speaker history) and plan to do an MTM with them and the M8N when time permits. All three of the drivers chosen really impressed me. I think the CD1.0 is a bargain at its price for a true ribbon. The 10F is stupid expensive for it's size, but at least it sounds very nice. I am preaching to the choir, but man that RS225 is nice. It looks nice, sounds nice, is built nice, and is super easy to work with for a metal cone driver. You seriously would have to spend at least double to come close to it in most Euro brands. Wish it had a bumped back plate, but I haven't bottomed it yet..

    The cabinet was kind of an experiment for me. It is curved and has very thin walls (1/4" only). The idea was to see how well I could do with a thin walled lightweight cab. I used 1/8" hardboard curved around a frame that remained part of the cabinet. The top and bottom cap are standard 1/2" ACX ply and the vertical frame is 3/4" x 1.25" sticks. The cab is then internally cross braced with dowels and more of the sticks. After the first layer of hardboard was adhered, I used a rubberized flooring adhesive (stays pliable) on the surface - all but the edge where real glue was applied, and placed the outer layer of hardboard over it to form a constrained layer. The inside of the walls had cheap ceramic tiles glued to it with construction adhesive and then applied a roll of rubber roofing sealer. The walls were lined with about an inch of fiberglass insulation. The mid chamber is sealed, a 7" x 4"id piece of pvc, stuffed with fiberglass and treated with rope caulk and the aforementioned roll of rubber. I surface mounted the mid and woofer but flush mounted the tweeter. The mid wasn't flushed because I wasn't going to flush the TC9, which had a thinner flange, and the cabinets were done when the new mid was picked. The port consists of a 2" id aeroport flange and just the coupling ring for length. It is very odd to me, but the cabinet is roughly 35L (gross), but DATS shows a lower tuning frequency than the port length would suggest. Perhaps some sort of TL effect occurring? Not sure. The baffle is two layers of 3/4" birch ply, faceted. Like I mentioned before, the baffle was originally stained and body textured black A500 style, but I ended up covering the baffle with gloss black VViVid vinyl. That stuff is amazing. It is so stretchable with just high hair dryer heat. The baffles were done in one piece. They show defects, especially up close, but it isn't the vinyl's fault, I just didn't prep the surface for vinyl application and it is gloss so it shows everything. black wasn't the original baffle color, but I think the look sleek. EDIT 01-03-17: I added the inner flare so the port is both flares back to back.

    It has a part or two in it.. I will attach the schematic. Crossover points are about 400 and 5k. All filters ended up being third order electrical. I didn't try for any particular filter or slope, this is just what ended up working out. I used Oil caps in the mid and tweeter circuits, only because I wanted to try them. I would have used two ASC caps in the mid section but they appear to have gone NLA so I had to do the Mundorfs. I'm sure Audyn q4 caps would sound fine too, just kind of like playing with different caps. I know I cheaped out on the mid inductor compared to the caps, but it is what I had on hand and is a parallel component. I will say though I am a fan of the steel lam buyout inductors. The oddly placed 1r resistor in series before the mid/high circuits was added after longer listening. The resistors in parallel with the mid and tweeter can be adjusted to suit the listener and environment. I voiced these on a downward tilt (started out relatively flat) because a lot of my music is unfortunately mp3 and or relatively compressed to begin with, and that Fountek driver is a little "honest" for poor recordings. They now sound on the warmer side, but not in a bad way. The impedance measurements are before a couple of minor resistor value changes in the mid and tweeter parallel circuits, but should be close. It is very much an 8 ohm nominal load, but I do prefer the sound on the 4 ohm taps of my 35w tube amp. Edit 01-03-17: Typical for me the longer I listen the more I tinker. The crossover resistors were slightly revised and resistor wattage recommendations were updated after running it through xsim. See the new diagram in post 2. The only thing not noted on there is that if the tweeter is a little hot for you, add a 47r in parallel with the tweeter to bring it down about a db.

    Well, I can't judge my own design, but will say I am very happy with them. Pics to come. Thanks for looking!
    Last edited by dynamo; 01-03-2017, 08:23 PM. Reason: I changed a few things about the design

  • #2
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    The measurement is on axis at 2m in a small room (xover slightly revised since this measurement)
    Last edited by dynamo; 01-03-2017, 08:33 PM. Reason: crossover revision


    • #3

      epi a500


      • #4
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        Original baffle and vinyl wrapped baffle


        • #5
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          Taking some measurements and crossover


          • #6
            Build pics to come when I have more time


            • #7
              Nice! Not to disagree with the Mrs.'s, the original baffles looked pretty good also. Looking forward to the build pics.
              My "No-Name" CC Speaker
              Kerry's "Silverbacks"
              Ben's Synchaeta's for Mom
              The Archers
              Rick's "db" Desktop CBT Arrays
              The Gandalf's


              • #8
                I'm with the wife, original was nice, but gloss black is Awesome! Great design, nice build and I'm jealous of the FR graph (darn flat)! Fantastic man!

                The "SB's" build page


                • #9
                  Thanks guys! I have to credit the 1/6th octave smoothing for the graph though! :D


                  • #10
                    You can still get the ASC's from several vendors. Pop me an e-mail....
                    "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:

                    My blog/writeups/thoughts here at PE:


                    • #11
                      I'm trying to upload some build pics but keep getting an error message (invalid file, but they are jpeg and open fine on the computer), so it might be a bit. I'll apologize head of time for the poor quality of the pics when they do show up.


                      • #12
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                        Here we go, size was too big. More bracing was added than what is pictured here, but this is the basic frame. The back was too tight of a curve to wrap with the Masonite, so I ripped a piece of pvc on a table saw and used that for the rear curve.


                        • #13
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                          The body panels adhered and pvc back piece on. I just used joint compound to fill gaps knowing I would not have a high def finish on the body. I sealed the body with poly and then primed it. The actual finish is Rustoleum spray on bedliner. The last pic is laying out where the chamfers were going to be cut on the baffle. I ended up with a lot of lines since I cut them with a skil saw and guide, so I had to determine where the cut would be and where the guide had to be clamped on. I lucked out and that actually worked pretty good.


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                            Baffle pics. The strips that form the double layer to accommodate the chamfer were opened up where they partly block the woofer hole. The pvc mid chamber worked good. I used a drill rasp to chamfer the back of the driver hole. It would be so much faster to route it ahead of time, but this wasn't too bad.


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                              Closer shot of baffle chamfer. I love the look of unfinished wood, wish there was a way to keep it looking dry and freshly cut and sanded like this forever. Also a shot of the sanded body. This is all I could find for build pics. I see some looked to have a date back to 2014..told you I work slow!
                              Last edited by dynamo; 06-12-2016, 10:00 AM. Reason: Fixed chamber to chamfer