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Discussion Starter #1
I was one of the lucky winners of the SI give-away contest. It took longer than I hoped, but my build is now underway.

Pre-veneered ply. Single layer all over - including the baffle (driver will be surface mounted). Dowels bracing up the wazoo. 4.2 cubes net. 8 of the dowels will span front to back, a line up with the mounting holes. Threaded insert will be sunk into each dowel, accepting 1/4-20 bolts as a means of attaching the driver.

I will start off using a BASH 500 plate amp already in my possession, but I plan to get a pro-amp in the near future. I'm not sure which yet, as I expect I will want to make a 2nd one of these. The graphs below show the model with and without the boots filter already in the BASH (high pass with boost. 2nd order, centered at 18.7 hz, with a Q of 1.3).

Having trouble picking an amp to handle the pair aptly. Maybe Inuke 6000?? I think if I had two of the 4 ohm SI's I could get by with a single ep4000 - but the one I have is the 2 ohm. One ep4000 would be great for a single, but ~630 wpc @4ohm stereo isn't quite enough.

Probably no better option than the NU6000 for $400. If I'm overlooking something, please speak up.

Okay, onto the build.















Rabbets mostly done here.


Dry fit looks good.


First glue up. Top/bottom to one of the sides.


Other side.


Double rabbets.


Dowels dowels dowels.



Preparing to glue the rear onto the cabinet.


Gluing (as it sits right now).


I wasn't sure how I was going to handle the excess PL. A little test with the flush trim bit revealed that it will come off very nicely when I flush everything up after assembly.


Larger versions of the pics can be found here.
 

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Wow, this is a great looking build to show off the new SI drivers! I'm excited to follow along with your build progress and see how everything turns out!
 

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Elite Shackster
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Are you sure about the Q of 1.3. Seems a little high and its not a level I would run. It will make for a pretty punchy sub but also your gonna lose a bit of the low end too. The model looks awesome though, good work.
 

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Discussion Starter #5
The Q of 1.3 applies to a high pass/boost filter already present in my current BASH 500 plate amp. after changing some resistor values years ago for my current sub. I'll only be using that amp temporarily.

Are you sure about the Q of 1.3. Seems a little high and its not a level I would run. It will make for a pretty punchy sub but also your gonna lose a bit of the low end too. The model looks awesome though, good work.
 

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Discussion Starter #7
I'm not there yet - but I'm anticipating it will present some challenges. My threaded inserts will arrive today from McMaster. I think the most challenging thing will be drilling straight receiving holes in the dowels. I only have a benchtop press. My dad's floorstanding press has some issues with the travel gears, so I may not be able to lower it enough for the 20" dowels.

I'll probably make some sort of jig involving my handheld drill. The plan is to cut the driver hole in the baffle before I install it. Then drill my mounting holes. I can then bolt the dowels to the baffle and see inside to make sure I've got my lengths right, and manage the gluing to the rear wall. Then I'll use bolts to keep the glue out of the threaded inserts when I do the final glue-on of the baffle to the cabinet and the dowels.

I think there is ample room for screw-ups in there, so I will be taking my time with all of that.

Woah, we have a build! And one with significant progress, too! Thanks for posting, Ben, I can't wait to see how this turns out. Did you have any trouble lining up the dowels, threaded inserts, and the mounting holes? That seems like it would be a tough job.
 

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Elite Shackster
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Lining everything up should be too problematic. If you place the driver on your baffle you can mark out all the holes. The dill those holes out with a smaller pilot drill, on the bench if possible so they go in properly perpendicular to the baffle. Once thats done, a quick pilot in the centre of each dowel should allow you to put you bolts or whatever into the dowels perfectly centrally. You should then use the baffle again to mark out the rear panel, and once gain the opposing ends of the dowels piloted out on a bench drill so the holes go in correctly. Once thats done, assemble the cab but leave the top off, fix the dowels to the rear first, then put the drivers in or temp fix the dowels to the baffle with small screws. Once all the glue goes off they wont move again and you should be free to finish the top and then fix the driver in as an when you please.

Just my 10 cents.
 

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Wow, what do you use to make those extremely detailed drawings?

This is going to be a great build to follow.

Thanks for adding the link to the other thread.
 

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Discussion Starter #13
Happy to share the build, guys. I don't get a lot of enthusiasm about this stuff around the house - except for my little boy. He likes whatever I like. Anyhow, I'll keep the posts coming.

I just finished for the night. I'll post some pics tomorrow... baffle hole has been cut out, threaded inserts and bolts arrived, and I'm now gluing my final non-baffle dowel, the one that reaches from the bottom to the middle of the rear panel.

So far this PL Premium has been working very well. It is cold in my garage, so I've been throwing a little heater at the box overnight. The instruction of adding a little moisture does make a difference. A mist of water on both sides of the joint prior to adding the glue speeds up the cure. It seems to get 80-90% cured overnight.

I do my modeling and renders in Solidworks.
 

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Subscribed. Another fantastic looking build.
 

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Discussion Starter #15
Here are the pics from last night.




First pass



My new down-spiral bit was very friendly to the veneer.


It fits!



Last of the non-baffle dowels. It was hard to get the 45's lined up on each side with no flat edges. Little wood piece wedging between two dowels as a clamp.


Here is the bolt and insert I'll be using.
 

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Looking good, Ben. Where did you source the hardware? I love the look of nice hex bolts instead of the usual boring wood screws, and I really like the idea of the threaded inserts too, just in case you want to remove the driver at some point and not damage the enclosure.
 

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Discussion Starter #18
Looking good, Ben. Where did you source the hardware?
Hardware is from McMaster-Carr. They are fantastic in every way (except that I can't link directly to a product).

Bolts: Item # 91251A548
Threaded Inserts: Item # 90192A124

Progress from last night.

When I first approached driver alignment for mounting holes, there was a little resistance. The corner of where the mounting flange attaches to the basket has a slight radius. Black shows the rub marks.


Tiny roundover fixed this.


Just before lining it up.



It dawned on me that I could use the doweling jig I had recently purchased. Worked quite nicely.


The first insert went in straight.


Recessed slightly so it doesn't get in the way when I glue to baffle.


This is why my inserts are not centered in the dowels. Centering them would cause the dowel to encroach on the cut out. It also allows me to swivel them slightly if any of these dowels are too close or touching any of the cabinet dowels. I drew it all perfectly, but my drawings and reality have slightly different tolerances. By first look, I won't need to shave anything down to get them all to fit.


These are the feet I'm using. Penn Elcom 9106. These things are a very beefy 1x2.5" rubber. I think they'd support my house. They attach to a flanged knock-in threaded insert accepting a 1/4-20 bolt.


Larger pics HERE.
 

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Discussion Starter #20
How are you going to keep glue out of the inserts?
With bolts, at least to start. I will mark the rotational placement of the dowels, relative to the baffle hole. I'll unthread the bolts most of the way, giving me room to apply adhesive. Then I'll cinch them tight, wipre away the excess, and put the baffle on the box. I'll add clamps to the baffle which will keep everything under pressure, so I can remove the bolts after a spell.

I might do the smart thing test this out before I go live. I have extra inserts and plenty of dowel scraps.

Early evening update:

All of the rods and inserts are set.


The true hero of this task was the robust t-handle hex wrench. Trying to thread in those inserts with a common L-shaped hex would have been a real pain.


Sneak peak.
 
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