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In conclusion: "Fenrir"...

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  • In conclusion: "Fenrir"...

    I was contacted last year by Rhythm Audio Design in Canada about doing a kit for them. Ultimately, the winter chill hit before the cabinets were completed, and basically, Old Man Winter only just recently relinquished his grasp about a week and a half ago. We had snow on April 20th here this year! (Prince was right yet again.) I did a lot of the gluing and finishing in my basement for this project just to get it done in time for InDIYana 2018. Even though this is a requested kit by a distributor, it is also requested to be open-source, and public information. The main reason for the name is that Fenrir is known as "king of the wolves" in Norse mythology, and really that's about it.

    More will come...
    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:
    http://photobucket.com/Wolf-Speakers_and_more

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

  • #2
    The look, and some background:
    I purchased some pre-cut BREX baffles at the PE Tent Sale back in about 2006, and they were pre-cut for a kit that PE no longer sells/sold. There was some goo on the faces, and some very minor scratches, and they had $2 stickers on both of them. So- I got those for just over $3. The wood that eventually became what the baffle set into, was a very figured pine 5-6 ply that HD had at one time about 7-8 years ago. I wish they'd had more, but this was the only sheet like it. I held onto it awaiting the project that the wood would be enough to finish a project. I had no idea these would end up in the same project.

    I received the drivers and made some initial T/S,¬*Z¬*sweeps, and prepped for a cabinet design. The drivers are Wavecor TW022WA06-4 waveguided 22mm silk dome and the Rival Acoustics R176-P-08 carbon paper 7" midwoofer.

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    The box alignment came out best to 18 ltrs. Larger, and the driver would unload easier,¬*so I only sacrificed a few Hz of low-end potential. The dimensions of the baffles I had dictated that the cabinet could only be¬*minimally deep. This also meant that the dual 1.5" ports that were approximately 8" long had to be bent to fit within the constraints of this pre-existing cabinet modus. This cab is tuned to about 40Hz, for an F3 of about 39.81 Hz just below there. It's a pretty standard vented rolloff. BTW- cabs were measured to be tuned to 41 and 42 Hz, so 8" is pretty close. According to the sim, the port mach does not exceed 23m/s with 25W input for an output of almost 102dB, where 26m/s should be the hard line drawn in the sand. The Xmax at this level does not breach 6mm (linear + 15%) until about 33 Hz, so it should be pretty well protected under moderate to¬*louder usage.

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    More 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:
    http://photobucket.com/Wolf-Speakers_and_more

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

    Comment


    • #3
      Hey junior - I saw the pic of those from 2018 diyindiana - I've got a boatload of those Rival 176 drivers on the shelf, so I'm real interested in your design.
      But the Unibox model you posted shows 1x driver in 18 liters.
      Inquiring minds want to know - 1x or 2x in 18 liters?

      I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
      "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

      High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
      SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
      My Voxel min sub Yet-another-Voxel-build

      Tangband W6-sub

      Comment


      • #4
        Should be 1 x in 18 liters based on what I saw and modeled.
        John H

        Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

        Comment


        • #5
          The picture I saw of the Fenrir did not look like a 36 liter box.
          Probably my mistake though.

          I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
          "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

          High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
          SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
          My Voxel min sub Yet-another-Voxel-build

          Tangband W6-sub

          Comment


          • #6
            Don-
            I don't know what you're referring to, but I had one woofer in an 18 ltr box. You could be looking at the Contender project from Brad Anderson in an MTM in 36 ltrs. I have not even mentioned 36 ltrs in this build thread until now in this very post, so I don't know where you brought that number from.

            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:
            http://photobucket.com/Wolf-Speakers_and_more

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

            Comment


            • #7
              Thanks Ben
              Yeah, now I see the Fenrir with the BREX baffle. Standard mt as you said.
              I was confused by the picture of the "mtm with the same drivers as the Fenrir"
              Apologies for the mixup.

              I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
              "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

              High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
              SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
              My Voxel min sub Yet-another-Voxel-build

              Tangband W6-sub

              Comment


              • #8
                Don did you get the P or the CP drivers?¬* Looks like they may have change the part numbers on the web site
                John H

                Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                Comment


                • #9
                  So- I set out to build the enclosures. I mitered the plywood edges so the grain wraps around the perimeter of the baffle; left side to top to right side. It looks pretty good that way too! The back is MDF, nothing special there. I had to make an inset inner circumference lip to allow the baffle to bolt down and seal up with weather stripping. I also added substantial bracing to stiffen the ply. IME, ply tends to ring when used, and I didn't want this to happen.

                  I braced the cabinet while including the ports in the bracing. This helps keep the ports from ringing, in addition to the bend and the angled inner exits. My thought process here was to try and reduce the column resonance associated with upper freq port harmonics, and the resultant dip in response it can cause. It's basically another form of end flaring by making the exit have larger end area than the main portion of the tube itself. Since the harmonic resonance is based upon length, I angled the ends thinking this would reduce it¬*while the average length still being 8".

                  I also ended up placing foam under the port bends, and across the inside top of the cab. I stuffed the central chambers with 100% Bamboo fiberfill from Natur-Fil, and then wrapped 5%/95% wool/poly batting behind the port tips, and then 4 layers of it between the drivers and the rear cavities in the box (not shown). This damped the box really nicely.

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                  At this point I finished the cabs. I sanded with 80/120/300, gently rounding the edges with the sander, and then applied high build polyurethane, wiped on by hand. I used 300g again to take off the raised grain, and then used with 0000 steel wool between coats up to 3 coats of poly total. They really shine nicely, but still have the bit of ebb and flow that I like to feel in wood texture. The picture below has 3 coats on the left, and 2 on the¬*right. The shadow makes the right look darker.

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                  More 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:
                  http://photobucket.com/Wolf-Speakers_and_more

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

                  Comment


                  • #10
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                    You can see I had to remove one leg of the bracing to allow the installation of the xover networks. As stated prior, the only damping missing is the 4 layer poly sheet from the upper horizontal brace down. I also had to carve the lower baffle mount lip to get the xovers into their respective homes.

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                    Since there was no easy way to mount the boards in this case, I just wedged foam in on top of the xovers to keep them solidly in place and from rattling. The barrier strip facilitates the wiring, and keeps the woofer xover in place.

                    I had to adjust the xover (more on that later) and then mounted the first cap in the central cubby of the box:

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                    ^^^There you can see the layers of poly I rolled back under the removed baffle to gain access to the filters.

                    More in the next post,
                    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:
                    http://photobucket.com/Wolf-Speakers_and_more

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

                    Comment


                    • #11
                      Originally posted by jhollander View Post
                      Don did you get the P or the CP drivers?¬* Looks like they may have change the part numbers on the web site
                      And of note- they are different coatings. I have the P-08, not the CP-08.

                      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:
                      http://photobucket.com/Wolf-Speakers_and_more

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

                      Comment


                      • #12
                        The xover I approached with a bit of skepticism as to whether the 22mm and 7" woofer would work well together. My thoughts were that the waveguide might allow this, but that I still might get a touch of beaming from the woofer if it needed to xovered higher than optimal. I took single axis measurements in the cabs, and these are what I got:

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                        You can see that the HD is rising 2nd order on the tweeter to above 1% below about 2.5kHz. This worried me a bit, but it was required knowledge.

                        Simulation showed this:

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                        This is what I started with, and I'll continue with the process later tomorrow....
                        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:
                        http://photobucket.com/Wolf-Speakers_and_more

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

                        Comment


                        • #13
                          What are you impression of these woofers and the others offered by the RAD site?

                          Comment


                          • #14
                            Looks like a very competent and well thought out crossover design to me. I am very interested in what they end up sounding like. I have a feeling they might be very nice and the drivers chosen look first class.

                            Comment


                            • #15
                              I like the look of the boxes a lot, they have a very nice style.

                              As far as the crossover, I suspect something close to 3k like you have will work well. This takes some strain off of the tweeter, the woofer has the surface area to easily handle the SPL. A little possible beaming might be a fine trade for the lower distortion on the tweeter, IMHO. Allowing a slight dip in the mid-range might be another option, that often sounds nice to my ears. How does the total phase and power response look?

                              Comment

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