SMJ ET CCTT Build

[theSven]

It's been long awaited on my part as well as waiting my turn in the queue to have Steve Manning help me with another speaker project for the theater. It wouldn't be fare to not mention Evil Twin either for making me practice my patience while he did the speaker and crossover work for this design. The story I shall try tell in this thread is the story of the SMJ Evil Twin Center Channel Technological Terror (SMJ ET CCTT).

It started out probably 2 years ago while the Ardent D's were being cut out at Steves in the shop, when I asked him about making a center channel for my theater that would perform to the level of the SMJ Ardent D's. I currently have a hand me down Boston Acoustics that a friend gave to me when I started putting a home theater together 10 years ago now! Wow does time fly by! Steve said he would come with some cabinet designs and that led to ET getting involved. 2 years later, or I think it has been that long the journey begins.

Once the center channel is built the next projects will be the NatalieP Ultra's for the side and rear surrounds. Then would like to do a DIY for the ceiling ATMOS speakers. If you asked me 5 years ago if I was going to build another pair of speakers after the SMJ Calliope I would have said maybe. Now It's a favorite of mine to do the finishing work and put it all together to use. I'm thankful for Steve and Jon in the DIY community for all their help in designing and fabricating my DIY setup for me to assemble!

Without further ado let the build thread begin 🎉

[technodanvan]

Let me know about those Atmos speakers. I was thinking of using the Seas MR18REX coaxial for that duty, along with some kind of woofer. Maybe an Anarchy if they're available.

[Evil Twin]

Your room configuration and the very specific setup issues have created a technological challenge which has required an extended effort.

At this point, the POC results are indicating that the time spent will produce satisfactory results- even today, my apprentice will be completing another phase of POC crossover updates and testing them by measurement and audition.

I would remind those who doubt the challenges to research the media and see how many actual tests of center channel speakers they can find, including actual measurements in a configuration similar to this one... the challenge is not trivial, and has acoustic issues due to positioning relative to boundaries which are not found with typical stereo music playback.

[Steve Manning]

Just to give an idea of the direction we're heading in terms of cabinet looks, here's a few pictures of the design so far.







I'm currently working through all the individual part drawings. Once those are done all the machining files need to be created. Along the way slabs of MDF and bamboo will be glued up for machining.

[Evil Twin]

He did not clearly elucidate the principle, but as Jonmarsh says too often, "Slow work takes time".

[theSven]

One design item to point out that I learned is that the speaker is built with the pieces of wood attaching to the base, meaning the speaker does not sit on the base and movable. I won't have to worry about having the speaker at the proper angle or if it gets bumped and would slide.

[JonMarsh]

That's correct- and the angle is based on your room and listening configuration.

Steve and I are swapping files back and forth. I'm going to tweak these imported STEP files with the rib round overs and some other bits when I get caught up with a computer storage rebuild (2013 Mac Pro, for ET) and get the tweak to the tweeter crossover wired up and tested (had to clamp and J-BWeld a switch to the POC Tweeter crossover board today).

Then I'll be updating the POC BOM and creating some "pretty" schematics with a new install of my old favorite (as used previously for Ardents, Isiris, etc) Eagle 6.6. Before Newark or AutoDesk got hold of it and messed it up. Yes, I have worked with those versions, too, so I am not just being snarky.


In the meantime, more teasers....






Slow work does take time, but we do get there eventually.

For reference, I do 3D Cad work in Shapr3D, from Hungary.

[JonMarsh]

And just the modeling views...

[Steve Manning]

Just one comment on the renders, other than Nice, the end caps will be black and not bamboo.

[JonMarsh]

Duly noted, and will be adjusted, along with other items

[JonMarsh]

Cosmetic updates here, but getting closer.

[Bear]

Stunning!

[Steve Manning]

Well nothing too exciting so far ..... parts are starting to arrive and glue up of heavy slabs of MDF is underway.

Woofers from Jon ....



One of many glue ups ......





1.5" thick slabs ready for machining ....



What's left to glue up of the MDF ....

[theSven]

I have the Tangband at my place and it needs to make its way over to Steve... May have to wait till March now due to my travel schedule.



This little guy is pretty heavy! Don't be fooled by the looks. This speaker is headed up to Steve's sometime soon for the build.

[JonMarsh]

It's a rather interestingly designed and built driver.

[theSven]

With my busy travel busy schedule for work I have not had a chance to get the Tang Band speaker up to Steve. I'm probably going to have to ship it when I get back to town in a couple of weeks. The weather is improving in my area which is good for when it's time to paint and assemble. I have enough clear and black paint for this assembly. Note to self, put plastic up this time and avoid having spray dust all over the garage 😂. I'm going to have to work on a new subwoofer solution too once this center channel is complete. The sub tube I have now was my very first DIY project. Another member on this forum helped me build that back in 2014. I'm not sure if I will reuse the Dayton Ultimax 15" or go bigger/smaller yet. More To Be Determined (TBD's) that need to get figured out.

[JonMarsh]

I know all about Notes to Self, heck, I'm the king of task managers, at least on the Mac. But my favorite is still Omnifocus 3... you don't want to see how much pending stuff I have, but this way there's a reasonable assurance tasks WILL GET DONE!

[Steve Manning]

Though it's been a bit for posting, things have been busy. I took a little detour on the CC project to make a new set of spacers for Sven's Ardent D's. Turns out we needed a little more breathing room under the cabinets, so that ought to be resolved now.

As for the CC project, most of the CAD and CAM files were finished and I got some parts cut today.









The cabinet will have 19 ribs total in 5 different flavors. This pile here is 12 of the 19.

[JonMarsh]

Mmmm, mmmm, good! I love ribs!

[theSven]

It's great seeing the progress on this project. I may have to end up shipping the Tang Band up to Steve. I haven't been home much of late, and the little time I am around it's laundry, some quick fixes around the house, and then time to leave again. I joke with myself that I'm going to have to schedule vacation to go and pick the pieces up when they are ready 😂.

[theSven]

Whelp 😭, got an email from Steve that the speaker spikes I have been using for my last 2 builds have significantly gone up in price. The ViaBlue spikes are now $379.00 USD for a pair of 4. Now I'm off to search for something similar to see what is out there. Steve has been sharing some links with me. When I get a list of options I will share in an up coming post. If I don't find something that I like I may have to suck it up buttercup and pay for the ViaBlue.

[JonMarsh]

Looking forward to seeing what you find...

[technodanvan]

Man, I should invest in a metal lathe!

[Steve Manning]

Man, I should invest in a metal lathe!

Yeah, I'm going to have to look for a machine shop for this kind of stuff. I talked with the distributor that I have been using for these for years and apparently Viablue wants to present themselves as a Ultra High End brand. So without changing the product at all, they just tripled the price ..... bingo, it's now Ultra High End!

[technodanvan]

I don't blame them I suppose, if people are willing to spend the money. But those customers they previously had (like us) will probably look for alternatives.

Edit: There are all kinds of hobby machinists out there, making these would be trivial for those guys. Maybe we should try to find someone willing to make something custom?

[theSven]

Yes we should look for someone and come up with an HTGuide version for the DIY'ers!

[Steve Manning]

I wish I still had access to the machinists that I used to work with, they made the spikes for me when I built my equipment rack.

[theSven]

Those are really nice!

[JonMarsh]

Yeah... this makes the bargain stuff I buy on Amazon for my budget builds look pretty reasonable.... (as used on my own Ardent D's, for example).

[Steve Manning]

So far the most "reasonable" option I've found is from Track Audio.



These are the little brother to these guys

[JonMarsh]

LInk?

[Steve Manning]

The link is - https://www.directaudio.net/product-...pikes-set-of-8

[Steve Manning]

Time for an update ..... started gluing some of the ribs together.







After some discussions with Sven, we decided to chamfer the edges between the ribs for a little more visual interest.





More parts waiting for glue.

[JonMarsh]

I like the chamfering between the ribs also.

[theSven]

I opted to go with the chamfering to keep the look similar to the SMJ Ardent D's and Calliopes. I hadn't even thought about that until Steve messaged me and then had to think about that.

[Steve Manning]

Well it wouldn't be an SMJ build without threaded inserts, so "some" of them are being installed.



These inserts will be used in attaching the baffle.



These will be for mounting the crossover boards. One on each end of the cabinet.



End caps getting glued in place

[Steve Manning]

Here is the last of the main cabinet glue ups.

To say this CC is a little on the "large" size is a bit of an understatement! I want to say ET is used to building one too many Death Stars!







Yes, that does say almost 28"!

[technodanvan]

Hey, at least you didn't have to bust out the 50" clamps! It's coming along real nice Steve.

[theSven]

Very exciting to see the pieces coming together. It will be another project where the pieces are assembled in their future home location due to size and weight. I'm also very happy that Steve is installing the threaded inserts and not me. Steve does a billion times better than I do.

[technodanvan]

Yeah, inserts can cause both literal and figurative pain. One of several reasons he'll be helping me with some baffles soon.

[theSven]

There is a thread on here that Steve Manning shared a how-to for making a tool to install threaded inserts. Perhaps in the few spare moments Steve has he could CNC the body of this tool and then sell the SMJ threaded insert installer to help DIY'ers do this easier.

[technodanvan]

It will be another project where the pieces are assembled in their future home location due to size and weight.

Out of curiosity, why MDF? That'll definitely add to the weight.

I see to recall that thread of Steve's. Right now I basically use a drill press and manually turn it while cranking down on the handle - only works for smaller pieces though. Otherwise I just use a T-handle.

[theSven]

Out of curiosity, why MDF? That'll definitely add to the weight.

I see to recall that thread of Steve's. Right now I basically use a drill press and manually turn it while cranking down on the handle - only works for smaller pieces though. Otherwise I just use a T-handle.

I guess cost? I'm not sure how much it would have costed me to use all Bamboo for this. On a plus side I've gotten pretty good at painting MDF now.

[Steve Manning]

Yep, this thing is heavy and since this is water resistant MDF it's even heavier then the big box store stuff. With bamboo being triple the cost, it seemed the sensible thing to do. Using bamboo for a better mounting surface for the drivers makes it worth the cost. I'm betting that most folks would not hear the difference if these ribs were bamboo, though that's not an argument I'm going to get involved in. At 1.75" thick this cabinet is plenty dead. Of course I'm willing to make speakers out of most anything you guys want ..... I'm hoping for a Richlite or Panzerholzt build one day!

[Evil Twin]

Here is the last of the main cabinet glue ups.

To say this CC is a little on the "large" size is a bit of an understatement! I want to say ET is used to building one too many Death Stars!







Yes, that does say almost 28"!

I find this effort to be most satisfactory… the Chancellor should be pleased with the results of your efforts!

[Chancellor]

Without question this build has been verging on becoming a true technological terror, but thanks to the assiduous efforts of all team members, the realization of the target concept seems imminent...

Now is not the time to ease off on efforts... here we can see that our faith in our friends has not been our undoing, but the source of success.




Still, do not forget the basis of the events of the last two years... Everything that has transpired has done so according to my design.

[theSven]

Without question this build has been verging on becoming a true technological terror, but thanks to the assiduous efforts of all team members, the realization of the target concept seems imminent...

Now is not the time to ease off on efforts... here we can see that our faith in our friends has not been our undoing, but the source of success.




Still, do not forget the basis of the events of the last two years... Everything that has transpired has done so according to my design.

Yes I agree that this is going to be an epic build and the juice was worth the squeeze waiting for the fruit to grow and other supply chain delays.