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    New Speaker build

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    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 1:06 am

    Seasonal greetings to the group.

    I'd like to self indulgently report on a new speaker build.

    I set out, in August, to start a pair of DTQWT (double tapered quarter wave tuned pipe) transmission line type speakers, which a forum member turned me onto. These are a design of Troels Gravesen, who has been likened to the "Nelson Pass" of speaker design. Many reviews confirmed that Troels is a talented speaker designer, and many examples of his various speakers have been successfully built and nary a complaint about any of them.

    I took exceptional care to execute the built according to the specified dimensions. (It's amazing how many people take liberties that surely amount to significant but random design changes!).

    I'm sure the time invested is over 200 hours, and far more than planned for, but the total cost was a mere $2846 Canadian dollars.

    This is essentially a 2 way speaker with an integrated sub woofer. As sub woofers go, it's not very "sub." The speakers play down to 40Hz, with a bass that the Who might characterize as "meaty, beaty, big and bouncy."

    Now for some pictures. . . .

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 1:12 am

    Hmmm.

    Sorry.

    No matter how many ways I try, I can't up load the photo. I'm pretty sure I followed the instructions.

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 1:14 am

    Here are a couple of links to my public drop box...

    https://dl.dropboxusercontent.com/u/21640362/DTQWT%20Mk%20III%201.jpg

    https://dl.dropboxusercontent.com/u/21640362/DTQWT%20Mk%20III%202.jpg

    Hopefully, if you click on these, you will see the pictures.

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 1:20 am

    I want to thank Alan for re activating my build to save money addiction.

    While these speakers apparently need a good bit of break in time, so far they sound phenomenal. They sport a Seas tweeter, Scanspeak mid-woofer and an Eminence Deltalite 12" woofer on the back panel.

    Building these requires access to a table saw, a router, and a belt sander. Fancier stuff you can do without.

    If anyone is interested in something like this, I recommend drawing out the plans on a roll of paper, then converting (re measuring) all dimensions from metric into imperial. Working with mm became a nightmare when it came to working with the wood. May as well have been rendered in microns. Tedious and migraine inducing.

    I would be pleased to consult anyone else through the various choice points in building these. Though time consuming, I have to say they are staggeringly good.

    How good? I don't know. I welcome any forum members to come over an tell me how they stack up against their own speakers. I'll just add that "our friend Alan" (as they say in the mafia) has some rich audiophile buddies who reckon these speakers hold their own with boutique speakers costing $15K and more.

    Alan has compared his own examples favourably against speakers costing more than that!

    peterh

    Posts : 680
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: New Speaker build

    Post by peterh on Thu Dec 10, 2015 2:37 am

    Very nice wood-work !

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 2:43 am

    Hi Peter,

    Why thank you for your kind compliment. :-)


    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 1:37 pm

    So I guess the main point I want to make for this forum is that this is a speaker that works well with our VTA amplifiers. My VTA ST 70 easily drives these to levels that fill the house with music.

    With acoustic music, I like to crank it to a natural level, and this is effortlessly reache, with plenty of steam left over, in a large living room.

    vtshopdog

    Posts : 69
    Join date : 2015-07-11
    Location : UT, USA

    Re: New Speaker build

    Post by vtshopdog on Thu Dec 10, 2015 5:23 pm

    Those look really nice - did you use hardwood ply or a veneer them yourself?  Love the hardwood edge bands.

    Troels designed speakers are on my list for next spring -  have exchanged a couple emails - he seems really nice.  Did you purchase one of the Jantzen Audio complete kits or source drivers here?

    Tube Nube wrote:
    If anyone is interested in something like this, I recommend drawing out the plans on a roll of paper, then converting (re measuring) all dimensions from metric into imperial. Working with mm became a nightmare when it came to working with the wood. May as well have been rendered in microns. Tedious and migraine inducing.
     

    I am very familiar with the nightmare of mixing imperial and metric in woodworking as the path began when I purchased a Festool track saw several years ago.  At this point have converted my shop to full metric and am extremely happy - (Quite a bit faster math and waaaay fewer errors!!  I will never go back . . .) but this involved a fair investment in Incra metric scale fences, a few hard to source router bits and other items.  Most the nice sheet goods seem to be metric anyhow (3/4" ply is actually 18mm etc) so fighting mixed scales one way or another.

    Congrats on nice build
    Tim

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 6:46 pm

    Hey Tim,

    Thanks for your interest and your comments.

    I used 18 mm baltic birch ply for most of it, and edged it with 6mm of birch hardwood most places. The about 1 1/2 imches (there I go again, mixing it up) for accent pieces on the front.

    I did buy the parts kit from Jantzen's, with the upgrade capacitor option. It included all but the Eminence 12" woofers which came from parts express.

    All in, it cost me about $2850 Canadian dollars, so you can figure on asomething like 75% of that as an estimate.

    tubes4hifi
    Admin

    Posts : 1292
    Join date : 2008-11-30

    Re: New Speaker build

    Post by tubes4hifi on Thu Dec 10, 2015 7:41 pm

    hey Doc Brenton, VERY IMPRESSIVE !! That's alot of money and alot of work, I'm sure you'll enjoy them.
    Much better than the single driver speakers you used to use!
    My summer project was a much more modest build of "Sunflower" speakers, around $500 in parts and probably 30 hours of labor.
    They are MTM open baffle on the top half, with an enclosed 8" bass on the bottom.
    I outsourced all the cabinetry making (that's not my talent, let me stick to electronics!)

    pedrocols

    Posts : 64
    Join date : 2014-11-24
    Location : Western MA

    Re: New Speaker build

    Post by pedrocols on Thu Dec 10, 2015 7:48 pm

    Very nice!

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 8:32 pm

    Roy and Pedro,

    Gracias amigos!

    Outsourcing is what Alan14 did, and I sure see the wisdom in having someone else do the cabinets.

    Though now that it's done, I can begin to romanticize the building process by forgetting the frustrations. I had the time for it, so it's a good way to save money and get a better speaker than I could have bought.

    I'm delighted to hear of your MTM speaker, Roy. I'll have to look that one up. How do you like 'em?

    PeterCapo

    Posts : 386
    Join date : 2008-12-05

    Re: New Speaker build

    Post by PeterCapo on Thu Dec 10, 2015 10:46 pm

    Really nice.

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Thu Dec 10, 2015 10:55 pm

    Thanks Peter.

    Hey Roy, those open baffles look great, and Im reading womderful reports of them.

    How do you like?

    TPW

    Posts : 7
    Join date : 2015-09-18

    Re: New Speaker build

    Post by TPW on Fri Dec 11, 2015 9:00 pm

    Very well done!

    Dogstar

    Posts : 93
    Join date : 2014-06-23

    Re: New Speaker build

    Post by Dogstar on Tue Dec 22, 2015 8:54 am

    I didn't realize wood was so expensive in Canada ...especially since Canada largest natural resource is probably lumber. Or are those drivers really excessively priced?

    Tube Nube

    Posts : 643
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: New Speaker build

    Post by Tube Nube on Tue Dec 22, 2015 12:00 pm

    Hi Dog,

    The wood itself came to almost $400. but it's mostly Baltic birch ply, which I imagine is imported. I don't know if I overpaid, but the cost at other stores locally was all about the same.

    The parts kit, iirc, was almost $2k, comprised of very high quality bits and pieces: drivers made by Seas, Superior Z caps, etc.

    I believe its a saving if ordering the parts kit from Jantzens, that is linked in with Troels' web page. Partners? Others have looked at doing their own sourcing, and reported it's the costlier way to go.

    Even in US dollars, it's still an expensive project. Looking at it one way, that was taking a bit of a risk.

    The bigger risk I was trying to avoid was spending money and time building a speaker no better than my last pair. I was fairly confident from reviews that this speaker would top my last. I haven't seen a bad review of them.

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