[dtsdig]

Happy New year! Since all of the summer and fall house project madness have died down, I am back in my shop finally working on the sub and speakers one of my brothers contracted me to build. For now, I am concentrating on the sub to get my chops back in the shop and then I’ll move on to the more complicated 1099 build.
After months of looking, I was finally able to get my hands on a 77 gallon fiber drum, like they use for industrial food and chemical storage. I found it locally for $42, which is way less than I was going to spend purchasing from Uline or the like. I could not use a traditional concrete form tube because trying to smooth over the spiral lines to get a nice veneer job would be a nightmare. These fiber drums do not have spiral lines and are perfectly smooth.
After cutting off the metal rings and endcaps on the barrel, I got to work on making a bunch of MDF circles.

I glued up double layers for each endcap where the Ultimax 18’s would be recessed

 

[dtsdig]

Next up was a center brace for the tube. I wanted to add some rigidity right in the middle. I figured a little detail wouldn’t hurt.

Here it is glued in nice and tight.

Next up was routing the recesses for the subs themselves and the Speakon which resides in the bottom endcap.

Endcaps installed.

I made an oops when I was flush trimming the end of the barrel to the endcap and routed into my Speakon recess. A little bit of bondo work took care of it.

Next I glued in some plywood blocks for the woofer screws to bite into.

 

[dtsdig]

Now comes the fun part. I had purchased some Hickory paperbacked veneer for this build. The only way I could see doing this was to roll the barrel onto the veneer. Super sketchy, but worked out perfectly. For those of you who have used the contact cement method, you know as soon as your substrate touches that veneer, there is no going back. Thankfully, I left 1.5 inches of extra veneer on each end of the barrel when I prepared it just in case the roll was not perfectly centered.

For finish, I am very fond of a product called Osmo, which you should all check out. It is so easy to work with and is super durable. It’s what I used on the butcherblock counter on the island in my kitchen. It leaves you with a nice, soft natural feel on the wood.

First couple of coats:

 

[dtsdig]

I picked up some mahogany to use for the “legs”. I got a pretty good deal on a 8/4 board about 11 inches wide and 49 inches long, which was perfect for what I needed. I chose to split the board width wise then resaw it to give me 4 boards about 5.5 inches wide and about 7/8” thick. It’s felt great to put my tools to actual work again instead of a random 2x4 on the chopsaw for some construction project.

I needed to cut about 2.5” out of the sides out each board so they would mount to the barrel.

After some cuts and detail work, these were all set.

On the outside edges, I wanted to put in a small inward curve so I had to make a jig to route against for each board. I have this hard TPU type tool made for creating your own profiles. You just screw it to a board in the shape you want then flush trim the board against it.

Next, I repeated clamping that jig to each board and flush trimming the curve.

Finally!

 

[dtsdig]

Here is what the legs will look like mounted to the sub.

The top and bottom of the sub will get black, round “tabletops” recessed into the center ends of the mahogany legs. That’s the project for this week. The MDF around the driver recesses will also be sprayed Duratex.

 

[MKtheater]

Looks great. That middle brace is not needed at all with sonotsubs. I know it is hard to imagine not needing one but once you seal the ends with the endcaps that tube becomes so solid and rigid. I use to stand on mine to show friends how strong the tube was with no bracing, just endcaps. Do you have a picture of just the bare drums you are using?

 

[dtsdig]

Looks great. That middle brace is not needed at all with sonotsubs. I know it is hard to imagine not needing one but once you seal the ends with the endcaps that tube becomes so solid and rigid. I use to stand on mine to show friends how strong the tube was with no bracing, just endcaps. Do you have a picture of just the bare drums you are using?

Hey MK, that would be the case for a typical concrete form tube, like the Sonotube brand but the wall thickness on these drums is much less. Still plenty rigid with bracing, but definitely not rigid enough to stand on the side of. The veneer has also helped toughen it up. Here is a photo of a similar one from Uline.

 

[MaxxCatt]

Looking good! Nice job with the veneer and legs.

 

[MKtheater]

Hey MK, that would be the case for a typical concrete form tube, like the Sonotube brand but the wall thickness on these drums is much less. Still plenty rigid with bracing, but definitely not rigid enough to stand on the side of. The veneer has also helped toughen it up. Here is a photo of a similar one from Uline.

View attachment 3077272

Ah, missed the part about being a food storage bin and not concrete form. Is this going to be dual opposed sealed or ported? I prefer dual sealed myself.

 

[johnson636]

Next up was a center brace for the tube. I wanted to add some rigidity right in the middle. I figured a little detail wouldn’t hurt.
View attachment 3077210



Next up was routing the recesses for the subs themselves and the Speakon which resides in the bottom endcap.

View attachment 3077262

Very nice round-over work on the Center brace. How did you go about routing the cutout for the speakon?

 

[dtsdig]

@MKtheater This is dual opposed sealed with Ultimax 18's.

@johnson636 Thanks! The center brace was very easy. I just used my circle jig to cut the center hole, maybe 8 or 9 inches round, then used a 6 inch hole saw on my drill press to cut the smaller ones. Finished it up with a small roundover bit and handheld router on all edges.
For the Speakon, I used the drill press set up with a 2" forstner bit to bore out the recess then use a 15/16" forstner to drill the through-hole.

 

[Zarkoff500]

@dtsdig Looking great. I like the attention do detail and can't wait to see how it all turns out. Thank you for the tip on Osmo. Looks like it is available on Amazon.com : osmo wood finish

 

[MKtheater]

Man, it sounds easy, I use rabbit bits for the recesses.

 

[Mashie Saldana]

That is looking really nice, I love the veneer and legs.

 

[MaxxCatt]

Man, it sounds easy, I use rabbit bits for the recesses.

I use rabbet bits, using rabbits is cruel.

 

[Tim Diebert]

This looks really awesome!! 👏🏼
Very MCM which I totally dig. Here is an idea I thought I’d share with you. I think it would look really good to notch the legs as I marked in this photo in red. It would look rad but also reduce the contact area the legs make to the floor. 2Birds....

 

[MKtheater]

I use rabbet bits, using rabbits is cruel.

Nice!

 

[dtsdig]

Thanks guys. For this build I had to pick up Jasper’s large size circle jig. Works great, just like the smaller one. Once I figure out which pin hole I need to use for the desired diameter, I use a sharpie to circle and label the hole, such as “UM18”.

For the driver recesses, since it takes multiple steps, I circle the pin hole and label them in order 1, 2, 3, etc. Makes it quick to setup for multiple baffles.
@MKtheater A set of Forstner bits are a must have for Speakon and things. Way faster than messing with rabbet bits.

 

[dtsdig]

@Tim Diebert I was debating about what shape to leave the uprights in, but once the “tabletops” are installed, the legs will look like I want them to, as-is. See my amazing drawing below. The inside corners of each leg will have a chunk taken out to hold a recessed MDF plate. The same will be true for the bottom and then I have low profile rubber feet that will be mounted to the lower plate. The mahogany legs may not even touch the floor. I’ll weigh my options there when I get there.

 

[Tim Diebert]

What is the total internal volume? 8cuft?