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Buyout PR Subwoofer Project...

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  • Kevin K.
    replied
    They look great Tom! And you managed to get all of the dust off of the drivers and PR's.

    +1 on wishing PE had more of the PR's, they are good looking.

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  • Derekj
    replied
    Sweet little project Tom! That plate amp sure is small too.

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  • tomzarbo
    replied
    A few more pics to illustrate the size.
    Triumph on left 9.5" cube..... Buyout PR sub on right, 10.5" cube. Coffee can on left, tape measure on right.






    Closeup of flush-mounted Passive. If I didn't recess it, it would have looked as goofy as all getout.





    Yeah, this setup sure does dig pretty deep. I played a few test tones on youtube and the volume didn't seem like it was beginning to fade until around 28 Hz or so... just by ear of course.

    Only lacking in Overall SPL I'd say. Those PR's are pretty nice, I really wish PE had more of them.

    TomZ

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  • tomzarbo
    replied
    Originally posted by Paul Carmody View Post
    You can put something next to it for a sense of scale?
    Yup, when I get home I'll put them side by side with a ruler and a water bottle or something. I need to get a better, closer-up'er picture also.
    TomZ

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  • Paul Carmody
    replied
    You can put something next to it for a sense of scale?

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  • tomzarbo
    replied
    One done...



    It's the one in for foreground. The littler' bugger behind is Wolf's 'Triumph' subwoofer that uses the neo version of the same TB driver for comparison. \/ --- Triumph on left, Buyout PR sub on right.



    I made Ben's 3/4" version, he also spec's a 1/2" version which would even be a smidge smaller. Doesn't sound like much, they're both small, but the Triumph for what it does in it's size still kind of amazes me....

    Anyway... this slightly larger setup works nicely. I was just a little bit concerned about building four of these things without ever hearing the PR in motion... they looked pretty high quality, but you never know of there will be some noise from them especially considering the price... but they're dead silent. They look very high-end too.... the rubber surround rolls around and becomes the outer flange trim piece. That means they need to be recessed to look decent, but when done, they look pretty nifty.

    I think I hear them digging just a bit deeper than the Triumph, but honestly, I can't be sure; they both go mighty low. It's a shame these PR's are NLA, they're pretty nice.

    In the pics though it's kind of dark you may see a sheen difference between the two. The 'Triumph' was finished with gloss rub-on poly, where these buyout subs were finished with satin, both from Minwax. My local Walmart used to sell Minwax rub-on in satin and gloss for $2-3 cheaper than my Home Depot. Now Walmart doesn't sell rub-on at all, and my HD only has Satin. No biggie I guess, but I'll have to find another source, sometimes I want the shine. This has only 3-4 good coats. I spend a half hour rubbing in with several applications per session. To say one session is only one coat's thickness probably isn't correct. It builds the more you apply, so 4 coats seems like enough for satin. Clear would probably need a few more to get uniform "shininess."

    I'm listening to it with a small pair of two-ways as I'm typing this and there's no lack of extension. That 25 watt Dayton amp is plenty of power for this driver. I like it. Thanks Kenny K! good idea

    Three more to go!

    TomZ

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  • tomzarbo
    replied
    Originally posted by scottvalentin View Post
    Will heatlock work with non-backed (raw) veneer? It notes on the website that it will, but I would worry about the absorption and the resulting wavyness/warping of the veneer. I have raw maple veneer.

    Thanks for the detailed explanation though, I will check out your tips as well as save what you wrote here as it is very helpful either way. I'm hoping to cut some wood this coming week so will start a thread.
    Scott,

    On that webpage where the glue is listed, It mentions that Heatlock is 'not suitable for crotch grain veneers' I assume because they tend to have 'openings' for want of a better term that will allow the glue to squeeze out through the 'pores' of the wood. Many non-backed veneers will allow some of the glue to move through to the surface as well. On paper-backed veneers, the paper/glue line stops the migration of glue through to the surface of the veneer... on unbacked veneers, that may not be the case. You may be alright using the iron-on method for unbacked veneers, but it's probably at least a bit more risky.

    Also consider that as you apply heat to the veneer as it bonds to the substrate, it will shrink a bit. That's why when you do a seam on a box with veneer, often you need to place something under the veneer like a wire or something to allow for some 'slack' so that the veneer actually overlaps by a 16th or so.... so when you iron it on, it will shrink to a perfect fit. If unbacked veneer shrinks too much, you may have some mild splitting, potentially allowing some of the glue to make it's way to the surface, and that's a problem for finishing.

    Think about it...You're applying water based glue to a very thin piece of wood for 45 minutes which will cause it to absorb some of the moisture... then you're applying it to a cabinet and pressing on it with an iron which will cause rapid drying/curing/shrinking. The paper backing prevents many potential problems.

    Truthfully though, none of these issues are probably deal breakers, and wood putty and some fiddling can fix almost anything, but paper backed is just much less problematic.
    The fact that you have maple, which is a very hard wood, is working in your favor. My suggestion if you have enough for 'scrap' is to try it out on a leftover piece of the same substrate you plan on making your cabinet out of. Not a tiny piece 2" x 3", but hopefully something a bit larger where you can see the shrinking in action. Maybe even b-u-t-t together two pieces of veneer, then iron them in place and see how much of a gap results after you're done.

    Lots of variables also, thickness of veneer, method of cutting, moisture content of veneer and substrate, etc.

    You may find that you'll make out fine in the end, and I hope you do. I'm looking forward to seeing your project!
    TomZ

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  • scottvalentin
    replied
    Will heatlock work with non-backed (raw) veneer? It notes on the website that it will, but I would worry about the absorption and the resulting wavyness/warping of the veneer. I have raw maple veneer.

    Thanks for the detailed explanation though, I will check out your tips as well as save what you wrote here as it is very helpful either way. I'm hoping to cut some wood this coming week so will start a thread.

    Leave a comment:


  • Paul Carmody
    replied
    Great project!

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  • tomzarbo
    replied
    Scott,
    Thanks for the kind words. Yes, I used heatlock and an iron for this. I almost always use that method, it's almost foolproof, which is good for me.
    Couple of things to remember...
    First the veneer needs to be "backed" veneer. The backing is usually paper, that works best with the iron-on method. Non-backed veneer will soak up the glue too much and get 'wavy', also the heat from the iron combined with pressure will cause the glue to 'bleed through' sometimes, happened to me once.
    Second, although several others have used Titebond glue to do this with, I've only ever used the Heatlock glue, which is designed for exactly this procedure, and I've never had a failure in say, 7-8 yrs and probably 2-3 dozen cabinets over curves and bumps. It works 100% if done right.
    Third, the glue roller makes it work. It allows for the glue to be distributed evenly with no 'dry' spots and no areas with too much glue which will not 'bond' with the heat.

    After you roll out the glue on the box, do the veneer. By the time you're done that, you may notice that some areas of the box may look a little bit dryer, (this usually happens on end grain with MDF) you can re-roll those areas briefly with a slightly wet roller (don't have to fully dip in the glue, just redistributing the existing glue on the box) and let it sit until everything is dry to the touch. When I say dry, I mean when you touch with your finger, you don't bring back any glue. If it's a little bit 'sticky' that's okay but the glue should remain on the box or veneer and it shouldn't be soft to the touch. Then you're ready to go. I use a fair amount of the glue on the piece, but not too much, you want it to be able to dry in about 35-40 minutes or so. If you put too much, it won't dry even, then you'll have to reapply. I pour the glue into a plastic disposable plate for picnics. When the glue dries in the plate the next day, I peel it off in one sheet and reuse it.

    My iron dial goes from 1-8, I use a setting of 5-6 usually with an all-cotton T-shirt scrap as a means of keeping the heat directly of the veneer so it won't scorch. Work center out and apply moderate pressure. After I think it's good, I "Pluck" the veneer with my fingernail to listen for any 'higher-pitched' noises that would indicate a non-adhered section. Also, I pay special attention to the edges and slightly press and roll the iron on the edges to make sure they are well adhered. And that's pretty much it. Like I said, I've had zero failures or lifting all these years so far, knock on veneer. The "Heatlock" glue is special stuff... it's very thick so it won't run down the side of an already veneered cabinet, and it isn't super-wet or moist, so it doesn't cause the material it's applied to to 'swell' with the moisture. They got the formula just right with it, and it's really not expensive for what it does. I know others have used Titebond with success, but I've found a method that works and I'm sticking with it.

    I have a few videos in my sig at the bottom of this post, a few about veneering. They're boring, but there may be a few pointers that may help or just seeing it done helps me sometimes. It's easy once you get the feel for it.

    TomZ

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  • scottvalentin
    replied
    Tom those look great and that Walnut really sings with the finish! Do you use Heat-lock glue for the iron on method or something else? I just picked up a roll of maple veneer and hope to improve from my first veneer job which was not that great. I used normal Titebond and the iron on method failed and the glue warped and bubbled the veneer. Oddly enough, I was successful using the 3M adhesive spray after the first 2 pieces failed.

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  • kenny_k
    replied
    Thank you Tom, but this is YOUR build and YOUR interpretation of the design. So, give yourself a well deserved pat on the back. I like your plate amp choice. 👍

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  • tomzarbo
    replied
    Originally posted by philthien View Post
    Did you use any software to model the enclosures w/ the passive radiators? Or did you model with a port and substitute the passive for the port?

    I guess I'm wondering how you model a sub w/ passive radiator, especially one that seemingly cannot have any mass added or subtracted.

    Nice cabinets, BTW. I've always enjoyed your cabinet work.
    I used BassBox Pro to model this setup. Again, Kenny K basically did the design and thought the idea up, I just tweaked it a bit to fit a particular size. BassBox does a good job of modeling enclosures and it does PR's just fine.

    There seems to be a "Sweet Spot" I've noticed with PR's. When I model them, it doesn't take much of a change in weight up or down to goof up the model a lot. It seems like driver/PR designers get the weight pretty good. There are many designs where no, or very little weight is added to the existing mass. This PR is heavier than most, but it seems to work well with this driver/box combo.

    Thanks for the positive comments. I love smaller projects like these, they don't take up too much time, but the reward is still big. I expect this sub to sound pretty good; should be done in a few days, I'll report how it sounds then.

    Kenny... build it! Yours will be a bit bigger but dig lower, right? BASS!!!!!!!! gotta love it.

    TomZ

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  • kenny_k
    replied
    Bravo! Great looking subs, wonderful job. Now I got to get off my bottom and make some. 😁

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  • WernerM
    replied
    Very cool! Gives me an idea to go along with the B652's I just got for my daughter.

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