Advice on building my A/V-3 cabinets...

Discussion in 'Home Theater Projects' started by PaulDF, Oct 11, 2003.

  1. PaulDF

    PaulDF Second Unit

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    I am nearly completed the basic buildup of my A/V-3 cabs, and am getting nervous before I glue the baffle on. I have not received the kit yet, but want to proceed as far as I can without it. Assumably, the complete cab should be able to be built, with all parts installed later, as prebuilt cabs are built/sold! Any other A/V-3 owners out there willing to help me out?

    Can the crossover network etc. be installed after the front baffle? how does the wire route down through the transmission line to the terminal cup? is it fastened in any way?

    Where do the crossover components fasten to? The internal components look pretty huge!

    I'll also assume that the hole cutouts are very accurate for a snug drop-in of drivers/terminal cup? Should the tweeter holes be countersunk after painting?

    Is it better if I just wait for the kit before I glue the baffle on? Could be 1-2 more weeks, and I'm going crazy. By that time I could maybe have the cabs painted as well (big maybe).

    I hate to pester Danny at GR again, so I thought I'd seek advice here, thanks.
     
  2. Joey Skinner

    Joey Skinner Second Unit

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    I just finished a pair of AV3s and on advice from this forum I built my crossovers and glued them to 2.5" x 5" pieces of 1/4" pegboard. I glued the inductors and caps to the pegboard. I think you could glue these assemblies to the braces with the baffle in place, just make sure the x-over for the tweeter will fit through the hole before you glue it the the pegboard. As for the wires to the cup, you could put some string through the transmission line before gluing the front baffle and then tie your wires to it and pull them through. I would countersink the tweeter hole before painting.
    Good luck,
    Joey
     
  3. PaulDF

    PaulDF Second Unit

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    Thanks Joey. So I would glue the pegboard to the top of a TL brace? They are the only surfaces not covered up by foam, etc. I was worried about the wire hanging down to the terminal cup, for possible rattling, vibration or otherwise against the braces. I suppose this'll make a lot more sense when I finally have a look at the actual kit parts.

    I've waited this long to build a good set of speakers, why not wait another week. I'd better just be patient.

    Thanks again
     
  4. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Paul, I've just built a pair of A/V-3 cabinets. I ran the terminal cup wire pair up through the cabinet through holes I drilled through the two back baffles, then caulked the holes. That way, the wires are fairly taught and are against the foam that's glued to the inside back of the cabinet instead of loosely hanging straight down and flapping against those baffle edges. For each cabinet, I glued the tweeter inductor and large caps to a piece of 1/8" plexiglas I had lying around. Also put a dab of glue on the tweeter resistor to afix it to the plexi. Being in the tweet circuit, it won't get too hot. Then, glued the plexi assembly to the second baffle. I glued the woofer inductor to another piece of plexi, along with the woof cap, then glued the assembly to the top baffle. The glue I used is Goop Plumbers Contact Cement/Sealant. It is tough and sticky stuff. It does not dry "hard", so there's no danger of it cracking over time. You could just glue the large components to the baffles, but I prefer nice assemblies that I can wire up out in the open, check out and then glue in place on the baffles.
     
  5. MikeSRC

    MikeSRC Second Unit

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    I'm also in the middle of A/V-3 cabinet construction and I'm doing the X-overs as Joey mentioned, with the woofer X-over glued to the top brace and the tweeter X-over glued to the second brace (per Danny's instructions). I like Hank's suggestion for running the wires down to the terminal cup and will likely do just that.

    I also plan on connecting all the drivers and make sure everything works properly before glueing the X-overs down or sealing the cabinet.
     
  6. PaulDF

    PaulDF Second Unit

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    Hank, great idea about drilling holes in the rear braces! Simple but smart. I might try that too, if I can find a way to drill back in there.

    Mike, also a good plan to try things out before gluing anything down permanently. Not sure if I would have thought of that. Another simple and smart idea. How would a person temporarily attach the baffle? Clamp it?

    Thanks for the tips, as this is all very new to me, and I have not had the components in my hand to visualize where they'll go. Also not sure whether Danny sends any instruction on any of this, since it is a rather simple procedure for anyone other than a noobie.
     
  7. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Paul, clamps work great. If your saw cuts are straight and 90-degrees, you won't need screws or nails (although for big cabinets, I do use a brad nailer to hold thinks in place before clamping, except for the front baffle). Tip: if your MDF parts fit snug, just use regular yellow wood glue. If you have some gaps, use polyurethane glue (like Gorilla Glue) on those areas.
    The instructions simply tell you to place the woofer xover parts on the top brace and the tweeter xover parts on the second brace.
     
  8. Joey Skinner

    Joey Skinner Second Unit

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    If you don't use nails or screws the panels are going to try to slide around when you apply clamping pressure. Where the panels meet you can nail small brads in about 1/8 in and then cut them off with diagonal cutters leaving them sticking up about 1/8 in. When you press the panels together the brads will keep them from sliding. Do a dry fit before glueing.
     
  9. PaulDF

    PaulDF Second Unit

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    Thanks guys, but my question was how do I 'temporarily' attach the baffle. For a test run, so I can still get inside the cab if something is wrong... I thought this was what MikeSRC meant he was going to do. Maybe I misunderstood him.

    As for the enclosure, I used biscuits to hold the rear and side panels in place while clamping. Not sure how I'll do the front. I had thought it wouldn't slide too much.
     
  10. MikeSRC

    MikeSRC Second Unit

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    I'm using nails with all the exterior panels, so I'm planning to just nail the front baffle on for a test. It's just to make sure everything's working correctly.
     
  11. Allen Ross

    Allen Ross Supporting Actor

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    i think pats idea of a removable rear baffle is great, as long as you get good edges on the joints and a good weather strip. plus you won't have to do a contortion act bending your arm getting into the small opening.
     
  12. Brian Bunge

    Brian Bunge Producer

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    I can't imagine why you'd need to get inside the cabinet. The foam will be stuck already and the XO parts will be behind the drivers. If there's a need to run new wire from the XO to the terminal cup either tie to the existing wire and pull through or use a string with some sort of weight on the end of it (nuts or something) to help feed it down the line.
     
  13. Joey Skinner

    Joey Skinner Second Unit

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    Paul, if you just want to test the speakers before glueing the front, clamps will work fine. That's what I did.
     
  14. PaulDF

    PaulDF Second Unit

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    Brian, you are quite right. There should really be no need to get into most areas of the cabinet when all is done. If the XO's are in the upper area then they are accessable anyway, and fishing a wire down is no real problem either if it had to be done.

    I've never done this type of project before, and am nervous like I said. I also overthink everything.

    Heck, even after all the engines and transmissions I've built, I still get a bit nervous in that moment before I fire them up for the first time!

    BTW, Danny sent me some info that comes with the kit regarding wiring, so I'll take a look at that. Thanks Danny.
     
  15. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Take a deep breath, Paul. We know how you feel. It's like firing up the rebuilt engine, wondering if you'll need to partially disassemble to take care of a boo-boo. My front baffles are clamped and gluing up in the garage as I type this. I triple-checked my crossover wiring and ohmed it out with my meter and I can reach through the driver holes to get to the crossovers if I need to. A removable portion of a back panel is not a bad idea for some speakers. You could mount crossover on it and it would always be easy to tweak/upgrade in the future.
    Anyway, just DO IT![​IMG]
     
  16. PaulDF

    PaulDF Second Unit

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    Okay, I PROMISE, when I get the time, I'll finish these babies.

    Can anyone link me to some XO pics? I have seen some in the past, but can't find them for the life of me!

    Also more questions...

    How short do I need to trim the foil inductor leads? And how best to solder to them?

    Also, do I need to worry about any magnetic interaction between inductors and caps? (As they will be placed quite close together)
     
  17. Danny Richie

    Danny Richie Stunt Coordinator

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