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Nice.

Going to be a nice box.

I included the plan views that Mose produced. Maybe you got the previous version.

Boy were you working late!

I used to do that until I biscuit jointed some finger tips on my left hand. No more late nights for me. And thankfully my fingers are fine to. I hope you can get your box from your shop to your listening room without having to punch a hole in the wall!
 

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Nice detail on the motorboard. It's a shame nobody will ever see it!

I also used glue on the biscuits and PL everywhere else. Worked well. The biscuits were great for mock-up and trial fit. Also made alignment during assembly really easy. However for the final lid, I only had biscuits on three sides and none in the middle or I feared I wouldn't be able to get the lid on.

Mark, I didn't send him the plan layout, so he must have got it from your packet.

...mose
 

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Discussion Starter #43
Thanks guys. I got your layout, Mose, and some other pictures, from Bob. I'm cross referencing Marks drawings, the layout, and my lines on the actual piece to make sure things are correct. I've already caught a couple little things that I did wrong as I drew it out. But all in all things match up really well.

Thinking ahead a little now...any opinion on whether the mouth should end up near the floor or ceiling? I'm willing to play with directional orientation, but flipping end for end does not sound like fun to me.
 

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You can leave them square if you want to. But cutting them at an angle gets you many more pieces. If you are nervous about the cut there is a way to cut them by yourself. You run the cut through your stock about half the length of your board. Shut the saw off with the board in place. Pull it out with the saw off and push it through the running saw from the other end. Saves your fingers from getting to close to the blade.
 

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Discussion Starter #46
One would think that a weekend would afford good opportunities to work on a project like this...mine did not. However I did get some time in last week, and although it doesn't look like I got very much done, I do have most of the pieces sized with the biscuits cut in, and test fit for positioning so that there are no surprises when the glue starts to flow. I have started with cutting and testing the bracing, and as I go I will attach the cleats to the pieces that need them so that there is less to deal with once the assembly starts. Hopefully lots of pre planning and fitting will pay off near the end.

I have a few pictures, test fitting the outside edges, cutting biscuits for the baffles, and a ready to install motorboard with bracing in place. I deviated a little from the plan in that I kept the outside a complete rectangle for now, aside from the horn mouth, and will cut those pieces near the driver enclosure out later, once the motorboard is in and I know things are square....thinking like a framer in that I love the natural ability of a corner to hold things square and strong while the interior is being assembled.

trio 7.jpg

trio 8.jpg

trio 9.jpg
 

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Discussion Starter #48
Oh me too...it seems that Murphy's been around my place. Start a project after so long a wait, and the universe gets jealous. Work gets busier, grass and weeds grow faster, daughters 16th birthdays roll around, etc etc etc. things will start rolling again this weekend. Thanks for asking. I'm trying not to be so perfectionist that I stall myself...just steady progress towards the impending earthquake.
 

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This is gonna be awesome. BTW where in alberta are you situated?
 

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Kadijk at least you are putting the right stuff in the right order.

And man are you going to have a heavy cabinet!
 

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Discussion Starter #51
I got to work in the garage this weekend, after all the hustle of life settled down a bit. It's not going to look like much in the pictures, and if you're not familiar with the internal workings of this cabinet not much will look like it makes sense. However 9 hours of meticulous measuring and shaping resulted in all my internal bracing being cut, sized, and prep'd for install when required. I cut air travel holes and rounded off all appropriate edges and test fit each piece so that when the glue flows there will be no surprises. It might not look like 9 hours of work, so I can be accused of either working slow ( which is probably most accurate) or of being overly picky ( maybe equally evil ). I look at it this way...no one is paying me to do this, so I can be as sloppy or careful as I want and time only becomes my enemy when I set a deadline for completion, which I won't. I am getting a strong desire to hear this beast in action, so things will not drag on too long. I did actually start assembly too, and glued the braces on the outside panel for the first horn segment so that it's ready to go when the panels start going into place. I'll glue as many cleats on as I can next ( seems easier laying flat than standing in place) and then start putting major pieces together.

By the way, I am in Lethbridge(I'll have to update my profile). I am also still thinking about mouth up at the ceiling or down at the floor...any opinions?

trio 10.jpg
All the bracing cut and laying basically where it will go
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Is the project possible with 4 sheets of material? If you're very careful with use...this is all that's left
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trio 14.jpg
The first of the assembly. Braces for the first horn segment. Here we go!
 

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I'd have to say that the internal bracing is the hardest part.

So if you have completed that you are doing well.

And it looks really good.

Exit will not really matter that much. The upper frequencies where this horn will work have a longer wavelength than your rooms floor to ceiling dimension. So you are in a case of choose your poison.
 

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Discussion Starter #53
4 days since my last post? Ouch, time flies when you're having fun. I got a bit busy with work and stuff, but did manage a couple of evenings to attach all the cleats and brace supports to the panels, baffles and braces. I liked the idea of doing it while the pieces are uninstalled so I could glue and nail them lying down on the work bench as opposed to standing up in the box, not to mention the small areas to work with glue and a nailer.

Yesterday I got started on assembly! :flex: It's nice to see the whole thing starting to come together. It's a bit of a patient slow process, because the glue needs to set and I don't have 100 clamps, but I've been able to come back to the project at different times of the day and add another piece and keep going bit by bit. It definitely helps to have all the parts pre made and pre fitted so that I don't have to be cutting and shaping and frantic while the assembly is drying. Maybe by the end of the weekend I'll have most of the main structure complete...

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first and second panels on and clamped!
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third panel on with bracing already attached.
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thank goodness for a brother and dad who also own clamps...
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fourth panel forming the bottom and giving the mouth it's shape
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motor board installed and clamped
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driver enclosure. It doesn't have alot of room back there
trio 22.jpg
first interior baffle forming the pinched throat in front of the driver.

This is definitely a challenging cabinet to build, but it seems to be coming together without a hitch so far. One thing that seems strange is the way that the PL Premium "reacts" as it dries. I'm not using it for the actual joinery, but using it more like caulking once the joints are solid. It actually bubbles, like something behind it is trying to gas off. Not sure what's causing that, and I'm not too worried because it's not causing problems. I just haven't seen glue do that before.
Can't wait to put it through the paces...:hsd:
 

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Looking great x 2!

The PL is actually a bit better than most PVA glues as it does a couple of things very well. It is great against shock resistance. And as it cures it expands. That fills in any minor gaps in the joinery. A horn has to be air tight along it's path length. You are telling the pressure wave off of the woofer cone what it's doing and where it is going by means of the horn path. If there are leaks there will be serious losses in efficiency. And close to the woofer there is serious amounts of air pressure. I have yet to find an affordable sensor to measure it, but I'm working on that.

Clamps are your friend, I have 300, so most of the time I'm OK. But more times than I can count I have had all of them in use at the same time on the same job.
 

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Discussion Starter #56
The PL premium is amazing glue. I do love it. It just seems too thick for the actual joinery. So I guess I've reduced it to a serious caulk.

Construction continues one piece at a time. I do have more pics but haven't had time to post them. The horn path is really taking shape now. And the box is gaining weight. All good signs.
 

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Well still looking pretty good.

A slow but steady route still wins the race.

As for PL not being good for joinery, remember that it is thixotropic, as in when it first comes out it is relatively thick. If you use it in a proper manner on a good fitting joint you end up with. Nice thin glue line. Try it if you are in doubt.
 

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Discussion Starter #58
I managed to pry the computer out of the kids hands for a few moments, so here are some progress pictures. Getting bored with the same old looks? Not me! I know there is progress, and every piece is one closer to finished and thundering. After tonight's glue session, all I have left in the main structure is the bracing, which all fits super good and should go relatively quickly.

trio 24.jpg
Closing up the first segment and moving towards the first turn.
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It still baffles me that the throat and first segment can be SO narrow. I've been building this unbeknownst to most of my friends, but the few that have seen the box so far can't believe the narrow, "restricted" horn path for the first 9 feet or so...they don't believe it will work. And I tell them, "Kravchenko designed it, so it's GOING to work!!"
trio 26.jpg
forming up the second segment and moving towards the second turn. Ready for bracing
trio 27.jpg
 

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Thunder.

Thundering.

Boom!

Kravchenko designed it so it works! Man, nothing like a little pressure. At least there is a prototype and a bunch of other builds to look back on. Yours is going to be very well built. Have you tried fitting in the bracing around the cleats? Sometimes some things get in the way.

And those buddies will be real handy come time to move your monster. Half inch MDF is 110 lbs a sheet if I remember correctly.
 
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