New AV15 Sneak Peek

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    JasonA on #3134

    I snuck in an hour or two this weekend and got a few more pieces cut. There are still a few outstanding pieces to machine, but it’s getting close to assembly time. I did a dry fit of the major parts to make sure everything was going to align ok, and much to my surprise it goes together quite nicely.

    As you can see, I still have to cut out the middle of all of the bracing, but here’s the basic “matrix” that makes up the internals of the box.

    stryke on #3135

    Still looking good. Any progress since then?


    JasonA on #3136

    Just a quick update. The weather has been pretty rotten lately, so I drug everything down to the basement and spent a little time with the jig saw tonight finishing up the bracing. I definitely like working with plywood – so much easier on the tools, and doesn’t make nearly as much mess as MDF. There’s a significant weight difference as well, which my back is thankful for. I have a couple more little details to take care of with the two ports, and then I can finally start some assembly. This is my first time doing something other than a rectangular box, and it’s definitely taking a lot longer than normal. I’m used to banging out a pair of cabinets in an evening. I guess this is an exercise in patience.

    So here’s what I have so far:

    And here are a couple views of the internal “skeleton”:

    JasonA on #3137

    Just another minor update. Got the initial assembly done. I’ll post pics, but there’s not much new/exciting to see. The one excitement of the night was that my brad nailer crapped out on me after about 2 nails… and I loaned all but one of my clamps to a buddy. Fortunately the one clamp I had left was long enough, so I used it to pull stuff together and then hammered a few 6d finish nails in to hold things together. That was a first for me 🙂

    So here’s what it looks like now:

    Nothing really exciting to note. There were a few concessions made in the design, but hopefully they won’t have detrimental effects on the end product. I opted for dual 4″ ports, rather than a PR. Initially I was just planning on powering this thing with a 350W plate amp, but after further consideration, it may end up being powered by a pro amp… possibly with 1000+W. The dual ports can handle the 350W without too much noise, but once you start getting above that, there could start to be some noticeable chuffing. Hopefully by having the ports on the back that won’t be audible. My old Lambda sub used dual 4″ ports and I only ever heard any hint of chuffing when playing test tones down around 20 Hz at high output… never noticed it in real-world use.

    Here’s a close-up showing how I mounted the ports (4″ PVC pipe). I routed a recess in the rear panel (which I built up with an extra 3/4″ scrap so I would have plenty of material for flaring the port on the rear) and the brace that the pipe fits into, supporting it securely at both ends.

    I need to pick up some 1/4″ plywood for the sides and start the lamination process. After the sides are in place, I’ll add another 3/4″ panel to the front (with neo magnets mounted from behind for the grill) and I can route for the driver and the rear port openings. I’ll flare the ports with a 1″ round-over.

    stryke on #3138

    looking good. If you can, use a 3/4″ roundover bit to flare the ports on the inside also. Not sure if you can do that now that you have it assembled though. Flaring both ends keeps the vent noise down quite a bit.


    Anonymous on #3139

    500w seems to be just warming this woofer up…I was a little surprised, I thought I would be fine with 500w, but its not nearly enough. Ive been running my amp bridged for more power, although its not rated for bridged operation at 4ohm. Hopefully it doesn’t go up in smoke soon, it doesn’t get much hotter, but I doubt I could sell it for what I paid for it. (used off ebay)

    JasonA on #3140

    It’s been a while since I’ve had a chance to work on the sub. Dealing with the curved sides took a couple of tests with various techniques (and several failures). In the end what seems to work the best are the strap clamps, along with a sprinkling of screws to help keep everything pulled together tightly. The strap clamps on their own don’t provide even enough pressure, so the screws do a nice job of adding the extra measure of safety to make sure everything is sucked together properly.

    Now I have to trim off the excess overhang so I can add the final layer of MDF to the front. Then it’s sawdust time with the router, cutting the woofer and port holes. Some joint/screw hole filling and it will be ready for veneer and finish.

    JasonA on #3141

    I found some time Friday night to clean up the curved sides a bit. With various power tools I was able to trim off most of the overhang, and then with some hand tools clean it up reasonably well. Next up is to add the second layer to the front baffle.

    simon5 on #3142

    Keep up the good work !

    PUREAUDIO on #3143

    that is comming out reall nice and i love the look of the sub.

    JasonA on #3144

    Well, I think I’m finally in the home stretch. Tonight I routed the ports, got the front baffle installed and cut the driver opening. I borrowed a QSC USA 900 power amp to see what this thing could do. All I can say is, it likes power :mrgreen: I just gave it a brief workout with the pod race scene, and with the amp in bridged mode I got the fan to kick in after just a few minutes. Soaked up all the amp was giving it and didn’t look like it was even working hard. I tried to get some excursion pics, but my camera didn’t want to cooperate. I ran some sweeps down to 18Hz or so and even with the amp dimed never sounded like I was running into trouble. The one thing I did realize is that I have some joints I need to attend to – a 30Hz test tone does a great job pointing out the air leaks 🙂

    Here’s where I’m at now.

    From here I think it’s primarily finish work. I’m planning on doing a cherry veneer, and I’m also considering doing some sort of “base” for it, although I’m not quite sure what just yet. I have some sanding, filling and sealing to take care of before the veneer can go on. If I’m lucky I might get to work on it for a few minutes this week before we head out on vacation. If I’m diligent, by mid July I may actually have the thing finished… if I’m diligent 🙂

    PUREAUDIO on #3145

    well when ever you do listen to it please let us know about it.

    paulspencer on #3146

    Nice looking box and bracing!

    The AV subs are quite power hungry. I used to drive a pair of AV12s (older version) with a pro amp – Behringer EP2500 – 650w into each. Each in a 70L sealed box. This amp was a good match for sealed boxes power wise. I ran them with a 450w pro amp and I’d call it “just enough” but with the higher powered amp I found I almost never ran them into clipping. I think if you want more output than you can get with ~500w then you are better off with multiple subs.

    JasonA on #3147

    Not a whole lot to show right now, but this project is working its way off the back burner. Three kids, a pregnant wife, and a hectic work schedule doesn’t leave much time for speaker projects, unfortunately. 🙁

    Tonight I spent a few minutes rough sanding and getting the joints filled with Bondo. With any luck I’ll find a few minutes this week to sand down the bondo and get it ready for veneer.

    I will be using some nice cherry veneer that I got from Tapeease. I used the same veneer on a set of speakers I just finished spraying, and I’m quite happy with how it’s turned out. As you can tell I’m going for the curved look 😉

    JasonA on #3148

    I managed to get the veneer on tonight – lots more fun than watching election coverage, that’s for sure 😀

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