Altec 2 Way Build ala JELabs - 802/32/414

Discussion in 'High Efficiency' started by marantzfan, Mar 8, 2018.

  1. ICTWoody

    ICTWoody Junior Member

    Does it matter if it's a rounder or a bevel? I was thinking a 45deg bevel that is about 1/2 of the motor board depth would look cool. Especially since this is baltic with those nice fine plys.

    - Woody
     
  2. Well, a bevel is still a diffracting discontinuity, but how much of that will you hear?

    Another thing to consider is that you must leave wood for the mounting screws!

    A deep bevel could remove some of the screw thread zone. Beware of that! The driver is heavy and needs a good fastener arrangement.

    If you must 45 deg bevel, and I agree that it would look very cool, keep this consideration in mind. There is not much spacing between the "bolt circle" and the cutout to play with, remarkably little for ambitious hole edge treatments.

    So, measure twice, cut once.
     
  3. ICTWoody

    ICTWoody Junior Member

    Thanks for the tips. I am taking a driver over to my friends tonight and I asked him about putting inserts in for longevity. Like I said, he's pretty seasoned as a woodworker and I think we'll be covered. I already asked him about adding a ring or a small cradle to help support the 414 because it only has the 4 mounting points.

    - Woody
     
  4. Good screw-in inserts would be an excellent idea.

    I'd think four #8 or #10 machine screws with locknuts under the heads should hold the 414 up. Again you have to look at the available real estate because insets take a much larger hole than the screw diameter.

    Four #10 deep thread wood screws would work. As for "longevity," you could rotate the driver a few degrees and find new wood each time you remove/reinstall it, which probably won't be often.
     
    Last edited: Mar 20, 2018
  5. Audionut

    Audionut Next Round Is On Me

    I was thinking of doing the same thing on my altec 604 opening but thought of not having enough meat to support the weight of the speaker. A simple adjustment to 22.5 or 33.75 router bit angle will provide the same effect and not compromise the hold of your screws. I was also thinking of putting a second ring inside the box and creating a more concave horn like effect (both 3/4 surfaces would have a taper of course). Here’s a sample:
    98AB260D-E31C-418C-9590-54D03E8CD775.jpeg
     
    Last edited: Mar 20, 2018
    ICTWoody likes this.
  6. Hey Fellows,

    I thought I would jump in here w some pics of my DIY WE 753 variant.

    Components are Altec 802B, Altec 32 B horn, Jensen P15ll Woofers in a braced 6cuft cabinet.

    Still tinkering w the xover but I couldn't be happier. I can't think of a better speaker diy project to do. If I can do it...

    Jensen build.JPG iphone 7-14 015.JPG SKINNED.jpg Myspeakers2 rotated.jpg mY DIY Speaker.jpg
     
    Last edited: Mar 21, 2018
  7. Beautiful cabinets!
     
  8. marantzfan

    marantzfan Administrator Staff Member

    Those cabinets are gorgeous! So, did you end up rear mounting the horns or did you veneer over the lip?
     
  9. Super nice! Wheres the xo point?
     
  10. Wntrmute2

    Wntrmute2 Junior Member

    I'm jealous of those that can turn wood into works of art. I really like the horn mounted inside the cab.
     
  11. That aesthetic is Shindo (RIP) like, in a good way. Really nice stuff!
     
  12. Wntrmute2

    Wntrmute2 Junior Member

    I'd like to find some cool 50s - 60s grill cloth like your's. Any suggestions?
     
  13. marantzfan

    marantzfan Administrator Staff Member

    Have you looked at any guitar supply shops? Some of the guitar amp cabinet cloth looks pretty retro.
     
  14. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Welcome to The Haven @doglv :)

    Beautifully constructed speakers.

    Bet they sound great! :)
     
  15. je2a3

    je2a3 Junior Member

    Welcome to the forum!
    Is this a vintage Jensen and the same unit used by @Salectric? Just curious, thanks!

    JE
     
  16. I’m not exactly sure what you guys are talking about here but I thought I would show you what I did, which is not to imply it is correct. But maybe when I figure out how to take some good measurements, we can actually see the effect and experiment w alternative solutions. I agonized on how to do this and eventually said… f@#& it, I’m going to make it look good and hope for the best. I placated my audiophile nervoses with the thought that “it’s a woofer w big sound waves" and the effect is minimal in the grand scheme of things. I also took some cues from Shindo... if you look closely at those speakers, they have the same “edge”. I used a strip of veneer to “finish” the hole. It turned out great… aesthetically anyway.

    picspkr20.jpg

    Thanks Sal. I couldn’t have put these together without you. Fellas- I want to tell you all a story about one of the good guys in the DIY audio community. I was very green when I thought about making these but I had one thing going for me… I knew what kind of sound I wanted. So, after perusing the internet I finally found JE’s site, and bingo!…. I found the speaker. Now I had to find someone who could tell me how to do it. From my very first inquirery about Sal’s 753’s he was incredibly gracious with his time and knowledge… to, at that time, a perfect stranger. He was sooo patient and answered every ridiculous question I had without a smidgen of attitude. For example, after one of my questions about his crossover he answered just as straight faced as a neophyte could hope for… “Doug… it’s a resistor, not a transistor”. Little did I know when I started this journey I would end up with great sounding speakers AND a friend.

    I routed the outline of the horn’s lip so it would sit flush in the unveneered plywood box. Then I veneered “over” the lip. If you’ll notice in the picture, it’s not perfect. The 32 horns, especially the metal ones, are far from uniform, so, its impossible to get perfectly fitted. There are air gaps that still need tended to. I contemplated various caulking solutions but was afraid caulk wont last the test of time and removing dried up caulk will be impossible as the horns are permanently attached to the cabinet. Thinking about other solutions, like stuffing w high quality felt. Another note, that’s not insignificant, is the width of the veneer. My cabinet making buddy helped me mill this veneer from a 12’ long 4” thick slab of black walnut that had been drying in my garage for 10 years. He called it a rich mans veneer as we sliced it thicker than usual. That thickness is key to veneering over the horn… if it were thin, like most “bought” veneer, it wouldn’t work.
    picspkr5.jpg

    The xover is at 2k. The xover is a variant from JE’s site and modified by Sal w a high end boost network. I have taken some REL software measurements but don’t want to post due to my incompetence. But, I know I have a 10db suck out just above 200Hz. Not sure if that can be addressed via xover or not. I have half walls, both suspended floors and ceilings and a glass wall on the right side, so…??

    Someone told me that my xover is too high for the distance between the horn and the woofer. If I had to do things over again, I would have made the horn and woofer a bit closer. As you can plainly see in the pictures the original 753, the drivers/horn is slightly closer. Although mine are the same as the Shindo’s… so, maybe not an issue. But, I was told that a better crossover point would be 900Hz at the distance I have mine.
    we753 back.JPG
    picspkr1.jpg


    A few comments regarding the booster network: I’m getting roll off around 10khz. I have not tinkered alot here, so I can’t give you much practical experience. I’ve been working on the other end of the spectrum and will eventually get to the top side but can’t say I’m wanting for much as it sounds really “right” as is.

    I could go on and on w questions etc… about xovers but I’ll stop here for now. I really look forward to getting yours and the groups input on the subject. Very curious as to how you use autoformers, etc.. Way more to come here, I hope.

    Thanks. I have a cabinet making friend who had the tools and veneering chops to guide me through the process. I did most of the grunt work, helped clean his shop a few times and he did the technical cuts and told me where and how to tighten the clamps. He has impeccable taste in music and we had some great jam sessions. It was fun and I learned a lot. Every time I came home from a session… I would tell my wife- there are no dumb, good carpenters. His on the fly grasp of geometry is nothing but remarkable.

    Thanks. The speaker is all WE 753 but Shindo was obviously a huge inspiration aesthetically. My house is mid century design both in and out and I was looking for something along that ilk. Here’s some pics of inspiring 753 variants... in my opinion, the most beautiful speaker ever made.

    homage 755-2.PNG View attachment 5281 hommmage ken.PNG 753 great pic.png Shindo Petite.PNG
    Google Richmond Design Inc.. And/or type “vintage radio grill cloth” in Ebays search engine.

    I asked for a sample of 5 or so designs and let the wifey pick the final 2. I then took the samples to Kinkos and had color copies made to size and taped them in place and then the boss made the final decision.

    I had a simple wooden frame built from a caning and seat weaving supplier. To make a small and strong frame is a delicate and difficult thing to do although is doesn’t look like much. I then took the fabric and frame to a frame shop and let the pros stretch the material and hot glue to frame. I attach w 3M’s stretch and release two sided tape.

     

    Attached Files:

    Last edited: Mar 22, 2018
    Martin G, Audionut, je2a3 and 3 others like this.
  17. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Great speakers.

    You are a talented woodworker.

    I think you will find many kindred souls here at The Haven. :)
     
    Audionut likes this.
  18. Doug, thanks for the nice comments and thanks too for posting the terrific photos of 753 inspired speakers. I especially love the finish on the one in the porch photo. Doug somehow manages to locate the best photos and most obscure information on the internet.
     
  19. marantzfan

    marantzfan Administrator Staff Member

    Ok. That WE speaker is gorgeous. I love the slatted front over the front baffle and has led me to look up other speakers built with a similar design and aesthetic.

    I came across this one, which I think it pretty handsome.

    image_68288.jpg

    http://techtalk.parts-express.com/f...stern-electric-we753-speaker-build-for-friend

    Now, I'm starting to think about replicating the look of this one... Oh how these things take one a mind of their own...

    I love it. ;)
     
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  20. On your 200hz suckout. look at a table of wavelengths of sound and compare to dimensions of interior of cabinet.

    If any dimension is 1/4 wave of 200hz, that means that the refection back to the cone will be 1/2 wave or 180 degrees out of phase and cancel.

    I just installed a 1" thick rockwool board in my WE 728B equipped "753 cab" to get rid of a narrow 400hz suckout. I put it in at an angle from front to rear so that it will destroy standing waves along the vertical axis as well as front to back, and screw with side to side reflections also. Suckout is gone and it tightened up the sound quite a bit otherwise.

    i glued two wood slats to the rockwool for added structural stability.

    A 4x2' 1" rockwood board is $12.99 shipped from Amazon Prime. Enough for two speakers.

    Pic is sideways. Bottom of cab is where the wire comes out. Rotate in your mind.

    IMG_0157[1].JPG
     
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