Build Thread - SMJ Equilateral Subwoofer

[JimS]

These are looking great guys!! For some reason I’m getting as excited as Sven for completion of this build 😜

[Steve Manning]

Well can't let Jon have all the "fun" ...... I've been working on some fiddly bits of late. Rounding over all the through hole edges on the bracing and trimming some verticals to length with beveled edges.

Today it was finally time to break out some glue and slather up the first brace assembly.









This is certainly a multi step process even with extended Titebond glue.

[Steve Manning]

With all the pieces glued in place on the first brace assembly I started laying out and cutting mortises on the first baffle.



Fortunately I've been able to get most of these mortises cut in the middle of their respective boards. Believe it or not that's not as easy as you would think given the cost of Festool products. I think their Domino could use a few improvements to help with that.











Slowly bit by bit .....

[Steve Manning]

Well despite the usual interruptions from life, some decent progress was made today.

Side panel mortises were laid out and cut on the first cabinet.

Cabinet with just the sides attached.





Adding the baffle to the mix .....











As expected this thing all of a sudden got rather heavy, I'm thinking 90-100 lbs already. Time to break out the lift table.

[JonMarsh]

That’s the problem with these big project- and that’s just a single 12!

[technodanvan]

These look really nice Steve, lovely work thus far!

theSven Did you mention somewhere what you would be powering these with?

[theSven]

The photos look amazing! Seeing this come to life from the CAD is really a thrill.

These look really nice Steve, lovely work thus far!

theSven Did you mention somewhere what you would be powering these with?

I have a pretty old Behringer now, but I want to upgrade to something new for these that has a trigger. I have to dig through email, but I think Steve Manning shared some amps with me in the past, but I can't recall at the moment if it was him or another member I was chatting with. One option was the JL Audio amps. I had looked at the Crown. I'm open to suggestions and it's something to explore...

[technodanvan]

JL is interesting, I didn't realize they had a line of home amps they sold separate from their home subwoofers. May need to explore that a bit for my own little project, when the time comes. Of course, depending on what receiver you use you may have Dirac (or similar), which might negate some of the need for some of the fancier bits on the JL. They also don't seem to post specs of the amp which is a bit concerning to me.

Crown is a popular choice of course, and for good reason. I thought Monoprice had one but I can't seem to find it anywhere. I had been looking at SpeakerPower plate amps but they also make rack-style amps too (https://www.speakerpower.net/collect...ack-amplifiers), I thought they used to be USA-made (if that's important to you) but I can't seem to find mention of that anymore? If you peruse AVSForum, you'll note the DIY section is almost entirely about overkill subwoofers - they use things like bridged pro amps from Powersoft (X series?) and various Chinese clones of other power amps...which maybe aren't as good a value as they used to be, given the tariffs and such.

If you're looking at JL prices you could also consider purchasing or DIYing an NCore or even Purifi amplifier. NCore has a new (presumably) 1,000 watt module coming soon to OEMs (https://www.hypex.nl/products/amplif...ly/ncx1000-oem) that may be fairly competitive in pricing.

Edit: I use NCore FA502 plate amps on my CSS subs - bridged 500 watt modules for something around 1,000 watts each. They come with fancy DSP that I really don't need for what I'm doing, but it gets the job done with minimal effort. Maybe something similar exists in a rack-style amplifier?

[Scareurpasenger]

I have been happy with my crown for subwoofer duty.

[JimS]

@sven I’ve got a k2 currently gathering dust you are more than welcome to borrow/test until I decide if I need subs with the ardent d’s.

[Steve Manning]

Here's a few of the things I've managed to slip in with life's list of chores.

Started installing some of the inserts .... though it looks like I ought to be sending these on over to Danny!



I broke down the bamboo sheets for the tops, bottoms and corner assemblies.

Here is the first panel glue up for a set of corners.





I decided to change up how I was cutting parts and bought a roughing bit.



This thing goes through bamboo like butter. Nice clean cuts



I also used it for roughing out the curved profiles



Things after final profiling .....





The area where the holes are is scalloped out for the binding posts in the rear of the cabinet.

[technodanvan]

What does a roughing bit do that is advantageous in this situation? I mean, I can't argue with the results as it looks great, but I'm curious.

[Steve Manning]

What does a roughing bit do that is advantageous in this situation? I mean, I can't argue with the results as it looks great, but I'm curious.

The readers digest of it, is the flutes have a serrated edge which helps remove material easier. Generally they are not used in a router, just CNC's. You can cut faster and quieter than with a standard spiral bit. This video goes over things, if your interested.

Generally you leave a little extra material on you cut line and then go back with a finishing bit and take that off.

[Steve Manning]

Work has continued on the corners. I had to make a jig to hold the parts so I could cut a 30 degree bevel on the edges.









I've also started mixing up some epoxy to begin glue up of the first cabinet.





I had to get creative with some wood scraps and clamps to get the appropriate sides more or less level for epoxy application.

[Scareurpasenger]

Nice work! I don’t think I would trust myself to get the tolerances correct on that.

[technodanvan]

No kidding, I'm lucky to get within 5 degrees of 90...

[Steve Manning]

Thanks guys .... though it's mostly wishful thinking on my part. No matter how much I try the wood always wins!

[theSven]

Steve Manning you make the woodworking look easy from the photos! Sure the wood may win, but I'm sure you put up a good fight showing it who is the boss.

[Steve Manning]

Despite many distractions from life, I managed to get the corners attached to the first subwoofer.









Second cabinet in the queue for epoxy and glue once I get past carpet installation tomorrow.

Then it's on to top and bottom fabrication.

[JonMarsh]

"Slow work takes time-"

Jeno Tihanji, former director of Siemens MOSFET development.

[technodanvan]

Wonderful work Steve, looks very cohesive. Are the corners already attached or are you going to paint the cabs before permanently installing them?

[JimS]

Wow, looking good!! 🤩

[Steve Manning]

Wonderful work Steve, looks very cohesive. Are the corners already attached or are you going to paint the cabs before permanently installing them?

They are glued in place with a rough sand done. I'll have to deal with the transition of clear to black during finishing .... I have a couple of options under consideration.

[Efalegalo]

Despite many distractions from life, I managed to get the corners attached to the first subwoofer.

Damn, thats beautiful!

[Steve Manning]

Thank you for the kind words

[Steve Manning]

Like Jon, I've had a multitude of things taking me away from the shop, but I've got some progress in. After getting the corners in place I cut a test piece to check how well the top and bottoms would fit if they we're machined to the drawings. Well go figure they would have been off by a small amount. It turns out that after cutting 17 individual pieces out and gluing them together all was not perfect, good, but not good enough.

I figured the easiest solution was to cut the tops and bottoms a little oversize and then flush trim them to size.









Here are the tops cut 1/16" oversize.

[Steve Manning]

The way I had to flush trim these pieces required getting a new longer flush trim bit .... one of Jon's favorites. Cutting the first part with my 2.25 hp Triton router I was less than happy with the experience. So more money was spent on a bigger 3.25 hp Mikita router with far better results. I also took a closer look at the speed I had been using on the bit and discovered I was running it too fast. The new router has a nice table on the side telling you where to set the speed dial.

Having more power and a better speed on the bit gave me a lot better control of the entire process.



The combo makes a bunch of sawdust!



The two tops trimmed.



I then put a 60 deg chamfer along the top edge and a small chamfer on the two mating surfaces between the top and cabinet.

[JonMarsh]

Looking very good, Steve- I have some of those 60 degree bits, been thinking about ways to use them! this was perfect!

[theSven]

Who doesn't love a new tool to play with? Glad you could find a router that has the power and ease to use for cutting the bamboo. The pieces look great on the cabinet.

[JonMarsh]

Looking very good, Steve- I have some of those 60 degree bits, been thinking about ways to use them! this was perfect!

BTW, folks, Steve is in the midst of a two day power outage, due to a transformer pole being blown over. Should be back up late tonight.

Stuff happens...

[theSven]

I was lucky and didn't loose power. I did get the strong winds that blew chairs off of my deck and the plastic I have down in the yard over to kill some weeds off with bricks. A bunch of trees down in the area too. VA gets wild weather all through the summer where it's like a hurricane 1 min and the next is like nothing happened...

[Steve Manning]

👋 I'm back ...... I must say that was not enjoyable! Not only no power, but no water either since we are on a well. Turns out this was not one of the round transformers but a much larger rectangular one. I discovered a number of our breakers tripped when this happened. Must have been a heck of a surge to the system .... I heard the bang when it happened.

As for the 60 degree bit, I agree it is a nice look. I would have liked to take a little more off, but that's about as big of a bit as they come. You want bigger it's time to buy a shaper!

[Steve Manning]

An update of sorts, though not the one I planed on ........

The idea was to post some pictures of the cabinet bottoms, well that hit a bit of a snag. That little power outage we had, apparently sent a rather large surge through the neighborhood. I had to reset all kinds of GFCI breakers in the house and shop and everything appeared to come back on ...... almost. I started into cutting the bottoms and found that my dust collector would not turn on. As one can imagine the big tools and the CNC in particular create a lot of dust and dust removal is a must.

After doing some troubleshooting I discovered the control board for the dust collector has some fried components on it ..... the magic pixie dust got out! So lets order a replacement ..... not so fast! Turns out the unit I have is discontinued and parts are no longer available. I have a request in for tech support for a possible solution but have not heard back from them. I'm hoping it's due to the holiday.

I been a bad month at my house!

[theSven]

Would home owners insurance cover the damage from electrical for the dust collector? Hopefully you hear back from the tech support people!

[Steve Manning]

Calling my insurance agent is on the list as an option

[JonMarsh]

This totally sucks... my sympathies!

This is one of the weak spots of a lot of fear- transient surge protection for the power supplies. The last rental we had, a similar Hubble home to the one we bought, the owners wanted the smart home accessory computer installed. Did it; a month later there was a line surge and power shutdown with Idaho power, and the surge killed the power supply in this Samsun controller module. That's part of why all of my gear is connected to heavy duty surge protected power distribution boxes, such as from Monster power and Tripp-Lite.

[JimS]

Wow, sorry to hear Steve.

[Steve Manning]

Thanks gents. I ordered an upgrade board today that I believe will solve the problem. 🤞If not, we try the insurance route which might be a long shot and with the couch cushions already searched we might have a problem trying to buy a replacement.

[Steve Manning]

Well after 2 weeks of very slow service from Laguna Tools I finally received the control board I ordered and as hypothesized it can be used for control of my dust collector!

Well back to making sawdust .....

[theSven]

That's great news!!! Glad you can get back to making sawdust!

[technodanvan]

Excellent news Steve!

[Steve Manning]

Well things are moving closer to the finish line, at least for cabinet construction.

Getting ready to attach the bottom of the first cabinet.



Epoxy and clamps applied.

[Steve Manning]

Test fit of feet once the clamps came off this morning.







This was the first time I used the 3/8-16 Rampa inserts. It was not easy to get them to go in straight to the bamboo using an allen wrench by hand . Though the cabinet sits flat, I pulled the inserts and will try again with the 10mm allen bit I got for my impact driver.

I've also started sizing the second cabinet bottom ..... it does make a mess!



And for those keeping track, the cabinet at this point weighs in at 120 lbs!

[JonMarsh]

Can you refresh my memory? What are those brass colored feet you are using? Source?

An inquiring mind would like to know...

[Steve Manning]

Can you refresh my memory? What are those brass colored feet you are using? Source?

An inquiring mind would like to know...

They are from these guys, https://edensoundaudio.com/

My go too had been ViaBlue but when they almost tripled their price it was time to look elsewhere.

[theSven]

They are from these guys, https://edensoundaudio.com/

My go too had been ViaBlue but when they almost tripled their price it was time to look elsewhere.

Yup, Steve found a new source with a super solid product that is much more affordable!

[JimS]

Those look great 👍

[Steve Manning]

Well both cabinets are now ready for the finishing process. My thought was to apply a couple of coats of shellac prior to the spray finish. The intent being to prevent bleeding of the black tinted finish into the bamboo which is to remain clear.

To help with that, I came up with a rotisserie of sorts to rotate the cabinets rather than trying to man handle them and potentially scratch up the finish.

This mounts in the driver opening.



This piece uses the holes for the binding posts. Fortunately I centered those in the back of the cabinet or none of this would have worked.



I made a couple of cradles and mounted them to some sawhorses for the spindles to sit in.





I used a piece of 3/8" threaded rod as a lock pin so I can flip the cabinets 180 degrees and lock it in place.



Not a perfect solution, but it should get the job done.

[Steve Manning]

Though slow, progress is still being made. Once I was finished with the shellac I got things set up for spraying.

This is at the beginning of spraying clear on the bamboo, in this case the bottoms of the cabinets.





I didn't take pictures of the entire clear spraying, but here are a few of the sealer coat prior to spraying them black.

[letiennam]

Those look great 👍

[theSven]

Looking very good! Looks like you have some good lighting in the spray booth setup. That makes such a big difference I learned from my last few builds.

[JonMarsh]

As we used to say in the old days, "Now you're cooking with white gas!"

Anyone also old enough to recognize this phrase has my sympathy!

Though slow, progress is still being made. Once I was finished with the shellac I got things set up for spraying.

This is at the beginning of spraying clear on the bamboo, in this case the bottoms of the cabinets.





I didn't take pictures of the entire clear spraying, but here are a few of the sealer coat prior to spraying them black.

[Steve Manning]

Well this project is slowly approaching the end, finishing at this point is complete.

Switched from applying sealer to black tinted topcoat.





Many trials and tribulations past before getting the black looking good enough to pull all of the tape and paper off. At which point a couple of coats of clear satin finished things off.











All that remains at this point is installing internal wiring and the binding posts.

[JonMarsh]

It's not slowly approaching the end, it's rapidly approaching the start of a beautiful listening experience for Sven!

In fact, this reminds me of how I think Sven will be feeling soon...