Announcement

Collapse
No announcement yet.

W6 sub

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • W6 sub

    After having so much fun building and listening to the W5 based Voxel sub, I knew that I had to build a W6-1139 variant sub.

    I felt that I wanted a little lower tuning, no chuffing, and little better power handing than the original Cerberus, but I didn’t want to build a 2 cube box to get that. I started modeling the woofer in about 23 Liters and 50 watts. I estimated at this point, that the driver would be happy in 23 L, and I’d use maybe 7-8 L for the port, so about 31 L total. Figured about 13X13X15 outside dims, which was really a bit too large for my location.

    Click image for larger version

Name:	params-unibox-50w-23-liters-3-inch-port.png
Views:	1
Size:	55.7 KB
ID:	1192484


    But for a 3 inch diameter port, the required length was 66 cm (26 inches).
    Lots of bends to get that working with PVC (my usual choice for ports)

    Click image for larger version

Name:	port-speed-unibox-50w-23-liters-3-inch-port.png
Views:	1
Size:	14.4 KB
ID:	1192485

    But with even just 50 watts, the W6 was over excursion starting at about 42 Hz.
    Response goal: I’d be happy with 30 Hz at 85 dB, and very happy if I could get 30Hz at 90 dB or better.

    Click image for larger version

Name:	maxspl-unibox-50w-23-liters-3-inch-port.png
Views:	1
Size:	17.5 KB
ID:	1192486

    But now the box was really getting too big.

    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

  • #2
    Re: W6 sub

    So I tried a bunch of tunings and box sizes, and suddenly, 14 Liters (70 watts with a SA70 amp) with a 2.5 inch port started to look real good:

    Click image for larger version

Name:	params-14-liters-unibox-70w-14-liters-FINAL.png
Views:	1
Size:	55.8 KB
ID:	1167394

    At first glance, maxspl and excursion could be an issue:

    Click image for larger version

Name:	maxspl-unibox-70w-14-liters-FINAL.png
Views:	1
Size:	17.4 KB
ID:	1167395


    Because of the slight “droop” of this tuning it looks to me like I will have much less excursion issues with this vs the 23L box, I know that room gain kicks in, and I decided that I really was never going to play it at 100 DB anyway.

    Here’s another sanity test – I remember Wolf suggesting a model for subwoofer xmax that added 10-15% to the mfrs xmax number. So here is the W6 with an additional 10% xmax, and 30 watts of input power.

    Click image for larger version

Name:	Unibox-max-spl-30w-13mm-xmax-28hz-fb.png
Views:	1
Size:	16.7 KB
ID:	1167396

    At 94 dB, I’m within xmax (+ 10%) down to about 26 Hz or so. Good enough!

    Port speed was good (length 89 cm / 35 inches):

    Click image for larger version

Name:	port-speed-unibox-70w-14-liters-FINAL.png
Views:	1
Size:	14.9 KB
ID:	1167397

    as well as W6 excursion / frequency

    Click image for larger version

Name:	peak-excursion-unibox-70w-14-liters-FINAL.png
Views:	1
Size:	13.9 KB
ID:	1167398
    Last edited by donradick; 07-14-2015, 09:42 AM. Reason: added content

    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


    • #3
      Re: W6 sub

      And at this point I knew that I wasn’t going to try to fit 35 lineal inches of 2.5 inch PVC into a box, I was going to build my first slot port.

      I spent about a week, doing about 7-8 models, going back and forth between Unibox (my favorite) and WindISD (because it can model slot ports with HP and LP filters).

      Final outside dimensions:
      11.5 H x 11.5 W x 13.5 D -- slot port used about 2.5 inches vertically in the bottom of the box. Minus the port, W6 displacement, and SA70 volume, the net interior volume should be right at 14 Liters.

      A 2.5 inch diameter round port = 31.67 cm squared port area.
      I figured that a port .6” high, 9.75 “wide = 37.63 cm squared port area, which required a length of 89 cm or 35 inches.

      Someone said that even a minor deviation in port specs caused a distinct change in tuning, so I wanted the dimensions very precise, probably more precise than I could have routed some dadoes into the sides. So I played around with my table saw and a digital caliper until I got exactly .6 inches width, then cut a bunch of those out of .25 inch BB. The slot “shelf”, likewise, was cut from some .25 inch BB. I don’t hear any problems, and really there should not be a lot of force on the slots. (Is that really true?)

      BTW, big shoutout to “thekorvers” for suggesting a .6 inch slot port height in the PE TT thread “Cerberus Subwoofer Modifications”.

      For this method, I would need to build up the slot port from the bottom of the box, adding each shelf as I go.

      I also liked the fact that when I build a slot port this way, I can ensure a perfect seal on all sides, and minimize the amount of glue squeeze out hanging around in the port.
      For the slot build process, I glued 2 strips to each side corner, and decided to add another spacer strip in the middle to provide some stiffening.. I held the strips in place while the glue set with blue tape, and sometimes a brad if it was warped.
      Here you can see the front port exit.

      Click image for larger version

Name:	IMG_0032-slot-spacer-small.jpg
Views:	1
Size:	207.3 KB
ID:	1167399

      Since I was rounding over the front exit, I decided to round over the interior slot entrance. I glued some scrap to the .25 inch slot “cover” and rounded over both top and bottom for good measure.

      Click image for larger version

Name:	IMG_0049-last-slot-roundover-detail.jpg
Views:	1
Size:	78.8 KB
ID:	1167400

      Because I totally suck at planning in three dimensions, I finally taught myself Sketchup. Much better than my stupid pencil sketches. It took me about 15-20 hours of false starts and restarts, but I’m pretty happy with the results:

      Click image for larger version

Name:	side-view-slot-detail.PNG
Views:	2
Size:	345.7 KB
ID:	1167401


      Since I had . 5 inch BB unbraced about 12.5 x 10.5 inches for the sides and top, there was a bit of ringing on a knuckle rap. I decided that a cross brace was in order.

      Click image for larger version

Name:	IMG_0064-rear-view-slot-brace-detail.jpg
Views:	1
Size:	115.0 KB
ID:	1167402

      You can also see the top layer of the slot and the center stiffener. I needed to shorten it about 2.5 inches so that the SA70 plate amp didn’t interfere with “breathing”. The sims showed that shortening the length by this much would not change the tuning more than 1 Hz or so.
      Last edited by donradick; 07-14-2015, 09:48 AM. Reason: added content

      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
        Re: W6 sub

        In the next pic you can also see the “naked” BB treatment – I decided to try more amber shellac – I had big problems putting it on evenly (dried VERY quickly) – but the amber color matched up with the cherry veneer very nicely.
        Originally I had planned on a roundover of the outside edges of the baffle, but then realized that I really couldn’t achieve a nice clean line for the edge of the veneer.

        Click image for larger version

Name:	IMG_0090 - w6 - front and top contrast - smaller.jpg
Views:	1
Size:	168.5 KB
ID:	1167403

        Probably should have painted the inside of the slot black. Oh well.

        A similar view for the back and top.

        Click image for larger version

Name:	IMG_0091 - w6 back and top contrast-smaller.jpg
Views:	1
Size:	176.5 KB
ID:	1167404

        You can sort of see how I had to reserve 3 inches in the bottom of the box for the slot port, and place the SA70 up against the top.

        Speaking of the SA70, I like the clean power and controls, but it seems like it’s always a bit warm even when I turn it “off”. Thinking about going with a Class D plate amp if I build another one just for that reason.


        Just for grins, here’s a comparison of the voxel to the W6 :

        Click image for larger version

Name:	IMG_0083 - voxel vs w6 - smaller.jpg
Views:	1
Size:	116.5 KB
ID:	1167405

        I could have made the W6 a bit narrower and taller, and I still might do that on another build.

        Speaking of veneer, I had always used water-based contact cement, but recently noticed a bunch of lifting around the edges of my older builds (ackk!!), so I decided to make the plunge to iron-on white glue. I used a little foam roller, put 2 thin coats on the box and veneer, then ironed it on. No problems whatsoever – piece of cake. I LOVE THIS METHOD!. Sheessh, no more worrying about a bubble or missing a spot or an edge lifting.

        After I was all finished and the W6 was thoroughly broken in, I ran LIMP to verify the box tuning.

        Click image for larger version

Name:	limp-stepped-sine-FB-detail-final.PNG
Views:	1
Size:	25.8 KB
ID:	1167406

        Question:
        I’ve always thought that the exact Z min of the “trough” indicated Fb (which is about 29 Hz in this case), but the 0 degree phase angle is about 27 Hz or so.
        Which is the correct answer?

        In either case, tuning is very close to my design goal, so no problem.

        So how does it sound?

        WOW. I don’t think I’ve ever turned it up past about 1pm on the gain control.
        Shakes the house, handles very low bass with ease.
        Sounds tight and clean.
        Last edited by donradick; 07-14-2015, 09:53 AM. Reason: added content

        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


        • #5
          Re: W6 sub

          Very nice build and very methodical process to get to the finished product. That is a pretty imposing little driver! Are you going to do some in-room measurements? maybe compared to the Voxel?
          Nice job on the finish too. Did you use raw veneer or paper-backed?
          Paul

          The "SB's" build page
          http://techtalk.parts-express.com/sh...-4-(pic-heavy)

          Comment


          • #6
            Re: W6 sub

            Originally posted by bullittstang View Post
            Very nice build and very methodical process to get to the finished product. That is a pretty imposing little driver! Are you going to do some in-room measurements? maybe compared to the Voxel?
            Nice job on the finish too. Did you use raw veneer or paper-backed?
            Thanks Paul -

            I actually wasn't planning on in-room measurements, but I will now!

            Pretty happy with the finish - about 6 coats of shellac on the (paper backed) veneer and 1 coat of AquaZar water=based poly.
            (You know the drill "It looks good enough and I want to play this tonight!")

            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


            • #7
              Re: W6 sub

              That's a nice project! It looks like you may have crossed over from cool 'mini' sub to a full-fledged hairy-chested subwoofer, even though it's still compact.
              That little TB'er is a beast!
              Oh, did you use the neo or Ferrite version? I wasn't sure based on the comparison to the Voxel which uses the ferrite driver.

              TomZ
              *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
              *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

              *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

              Comment


              • #8
                Re: W6 sub

                Originally posted by tomzarbo View Post
                That's a nice project! It looks like you may have crossed over from cool 'mini' sub to a full-fledged hairy-chested subwoofer, even though it's still compact.
                That little TB'er is a beast!
                Oh, did you use the neo or Ferrite version? I wasn't sure based on the comparison to the Voxel which uses the ferrite driver.

                TomZ
                Thanks Tom!

                I used the ferrite version - the price difference could not be beat vs the neo.

                As indicated, I will probably make at least one more of these.
                I've got friends who can't stop drooling at Fry's bargains - looking for a 12" sub with 200 watts for $100.
                I'll bet this little guy will blow away any of those commercial mass-market subs.

                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


                • #9
                  Re: W6 sub

                  Here's Omnimic comparison of my W6 sub vs a stock voxel with 1/24 octave resolution.
                  Played OM Track 2, hope that's correct.

                  I don't know if this is the correct procedure - I set a level of 85 dB at one meter,
                  then measured close-miked on each system. It surprised me that the W6 (in Blue) was not
                  more flat from 30 - 100, but in any case you can see the Voxel (in Red) drop
                  off below 60 Hz. Still, the Voxel sort of shows an EBS alignment, with good output
                  well into the 30s.

                  Subjectively, the Voxel sounded like was working a bit hard during the test, while the W6 was shrugging
                  at the challenge.

                  Click image for larger version

Name:	W6 vs Voxel.PNG
Views:	1
Size:	15.9 KB
ID:	1167408

                  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


                  • #10
                    Re: W6 sub

                    Best writeup in many moons. Very interesting project!

                    Comment


                    • #11
                      Re: W6 sub

                      I could be wrong, but I think "track 4" is the Bass-sweep on the disk. Not sure if it matters though, since these aren't really playing anything over 150-Hz anyway.
                      That is a nice smooth "Blue" curve, with an actual "port tuning" dip showing at about 25-Hz. Looks like a very nice and solid sounding sub build.
                      You have peaked my interest.
                      Paul

                      The "SB's" build page
                      http://techtalk.parts-express.com/sh...-4-(pic-heavy)

                      Comment


                      • #12
                        Re: W6 sub

                        Thanks guys.

                        When PE cranked up the "Speaker Design Team" project, I realized that my documentation was woefully inadequate, so
                        I learned Sketchup and tried to put more details into the build notes. One aspect of this hobby that always surfaces
                        in any project is the revisions and alterations and changing decisions until it's finished.
                        I tried to capture some of that. But, sheesh, after a number of years at this hobby, I'm still in awe of the
                        writeups that some guys produce.

                        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


                        • #13
                          Re: W6 sub

                          Nice build and a great read!

                          BTW, the W6 is out of stock already.

                          Cheers, Wayne

                          Comment


                          • #14
                            Re: W6 sub

                            This project looked interesting to me and I have just started to learn Sketchup and used this as practice. An attempt was made to follow your dimensions in the text and I came up with some slightly different numbers.Click image for larger version

Name:	BOX 1.JPG
Views:	1
Size:	53.1 KB
ID:	1167412Click image for larger version

Name:	BOX 2.JPG
Views:	1
Size:	46.7 KB
ID:	1167413

                            Attached are a couple of sketches for your review.

                            Comment


                            • #15
                              Re: W6 sub

                              The venerable 1139 claims another fan!!!
                              Love these little mongrels,
                              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

                              Working...
                              X