Too cool
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Pretty cool looking.
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Possibly do a hybrid of printed front/back but plywood/mdf/etc midsection. That way you can make it deeper for more volume?
Yeah the MAC-05 seems to like alot of volume to play in.
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I’ve been trying to sort out the upper brace for the Mechano23 but I’ve been unable to make something doesn’t take up a lot of space. The problem is tworking around the port that is, more or less, centered on the three beams discussed below. I wanted to have it set up for different ports so I could play around, measure it, and see what looks and sounds the best. Additionally, there is some discussion at ASR about appropriate tuning so I figured I’d make the files public once done and let folks choose their own port.
This is my solution for the time being. The walls will be semi-hollow so I feel that stiffening them any way I can is important. Shown are ‘beams’ that would be inserted in each of three slots at the top of the cabinet. These would be different than just including them in the sides for a few reasons.
- Including them in the sides would just make their infill the same as the sides, unless I were to modify it in the slicer software. Since I don’t know what slicer folks use, and don’t know how compatible software is with this feature, I’d rather avoid that entirely.
- The sides of the cabinet will be printed in layers parallel to the baffle. I would print the beams such that the sides would be printed perpendicular to that in an effort to improve strength in the sides.
- Finally, since the beams are relatively small and can be printed quickly compared to the cabinet, I could increase the infill anywhere up to 100% if I wanted to.
I could potentially attach the three beams together at the far end (by the interior port opening) which would certainly improve things. However, I’m concerned that would partially block the opening on longer ports, potentially impacting the tuning.
I’m open to ideas!
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I have considered this and it may well be a path to take. Right now I’m trying to stick with roughly the same dimensions as the Mechano23 as I think it’s already pretty deep for what the average person would want.
Nice work, but can’t you at least simulate some veneer tear-outs or something?
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Ha! I suspect there will be plenty of errors over the several day prints that I’ll need to either deal with (by sanding or something) or just accept as the cost of doing 3D printer business. 
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I went back through my stock of parts and found I do have a pair of SB26CDC tweeters that I was going to pair with the SB15CAC30-4 for a small 2-way bookshelf. Some of you heard that one, Jim Holtz presented it at IowaDIY in…2024, I want to say. That cab was maybe a tad larger than what I was trying to stick with but it was definitely in the same ballpark. Something to think about since I have the parts for it.
However!
I cracked open the boxes to the CDC tweeters and they both exhibit a sort of yellowing around the edge of the dome, presumably adhesive or maybe a damping material that was used? Just want to check if this is normal as it’s…not very attractive. Hard to see in the picture, but readily noticeable otherwise. Kind of thinking about acquiring the STAC variant (fabric dome) for this project instead simply because of that.
I did confirm the color of the dome sort of clashes with the silver/gray MAC-05 as well, it’s just too white (other than the yellow).
Edit:
Random aside, but I see the new SB coax is on Solen. I would like to play with that!
Edit the 2nd:
The crossover and THD filter PCBs came in for the Mechano23. If anyone wants to make a pair let me know, I have 10 of these. And yeah, I paid a few bucks extra for white since I’m FANCY.
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I was thinking how sweet those looked in white before I got to this sentence. Nice job!
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My CDCs seemed to match well enough to convince. But, seeing yours, it seems the adhesive used to attach the dome to the former oxidizes yellow over time. I bet they extra yellow shifts the overall color visually too far away from the grey-white that the MAC driver cones have. Damn. Oah well. Not like that sort of thing hasn’t pagued speakers in the past.
I’ve got a pair of the Micro-C’s on the wall above my monitor and can confirm that the SB12CAC is NOT discolored around the edges. The surround &/or adhesive may be different material than the tweeters?
I can also confirm that the anodized coating WOULD NOT be a good match for a MAC-06 or MAC-04. It is flatter or less pearly than the MAC driver(s). I guess you could still use them together, but the difference would be apparent.
I think I’m overthinking the bracing for this. Top brace is weird because I need clearance for the port. I should need two ‘x-beams’ so I might delete the one furthest from center. Beyond that though, I’m not sure how I can connect those sides. Maybe I should just put a window brace in the center along with the lower crossover tray/brace and call it good enough…
As you might imagine, I’m a bit paranoid about the cabinet presenting a resonance issue.
Just tossing this out, and I could be wrong (a skill I’ve perfected over the years), but just thinking the bracing may be best out of a different material - ie old fashioned wood, for not only bracing but damping the plastic materialed box ?
I’ve been pondering that myself! I’m not sure what the answer is, but I have a few ideas.
- While I was originally designing the box for the Mechano23 for my own use, I also decided I would share it on at least one 3D printing website for others that want to tackle a somewhat complicated project. There are, of course, no promises that folks who can 3D print such a thing have the necessary tools to craft even simple wood braces. So, I think for the Mechano23 I’ll keep to plastic.
- HOWEVER! I am interested in combining materials for the Gifty series both from a performance perspective and an appearance perspective. To that end, I’m thinking of making a few test cabinets similar to that of the Mechano23. I’m thinking both 18mm and 12mm cabinets should be tested, perhaps with varying infill densities and wall loops. I’d make simple slots that both wood and plastic braces could slide into, perhaps three sets of slots as I did for the Mechano23, and do sweeps looking for cabinet resonances with no brace, one brace, two, etc. Ideally I’d find a combination for 12mm sides that worked well to give me more volume to work with while saving filament and print time.
- Probably wouldn’t hurt to see if interior surface treatments would make any difference as well.
- Of course, I need to do some research too. I’m sure at least some of this has been tested by the DIY community already. No need to reinvent the wheel.
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Maybe have struts coming off the port body that interlock with the sides?
I actually did that at first, until SOMEBODY (cough, TOTALLY not you… ) reminded me of the Optiport. I could do this once I determine the preferred tuning I suppose, but I like the idea of a port removable from the rear.
In other news a saw some links to this guy a while back so I watched a few of his videos. Looks like he’s done a few tests and runs a small business selling his designs. The video below tests infill density and raises a few good points, but he jumps from 10% to 30% infill (then to 60% and 100%), where I think the interesting information would be somewhere between 10% and 30%. His designs are also already braced pretty well (you can see a little of that in his video) so of course the differences are fairly minimal. He also didn’t mention how many wall loops he uses or the thickness of the walls. I’m thinking of buying one of his designs so I can see this information.
If you don’t want to watch the video, the result is there isn’t a ‘huge’ difference between any of them really. Minor improvement from 10-30%, another minor jump from 30-60%, then a bit of a dropoff at 100%. His recommendation is 30% unless you’re a discerning audiophile, then go with 60%. He’s also using PLA in place of PETG, I need to do a bit of research as to why. From a customer relations standpoint I’d argue PLA prints a little better/easier on some printers so it may be as simple as ensuring his customers get a good print. I also expect the differences to be minimal at best (unless you’re using these outside in the sun…then maybe PETG would have a slight advantage). so cost and availability could be a factor (PLA tends to be slightly cheaper and available in more colors/finishes).
Yesterday I started a long print for my first ‘complete’ cabinet at 25% gyroid infill with 6 wall loops; I chose this somewhat arbitrarily. It’ll use ~2.2 kg of PETG for this one, and the machine states 3 days + 9 hours to complete. We’ll see if it finishes without errors and what sort of quality we get.
Other printer is working on the first of that upper brace I was asking about. I set it up it’s split into six parts connected by dovetails. We’ll see how the tolerances are on that, I suspect with 6 wall loops there will be no ‘give’ so I’ll need to adjust by 0.1 mm or so.
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Using standard PETG for the braces may help, it being a bit more flexible. Or maybe a stiffer TPU?
I’ve designed and built a few 3D printed speakers (but nothing as complex or of your caliber!) and always line the inside with automotive sound deadening; butyl rubber. I found it works really well to reduce panel resonances.
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I think butyl rubber would be a great idea, though I may have overengineered the interior to the point that I have few flat areas it could attach to. Something to think about on the other designs - simple may well have been the way to go. I have been thinking about way to get some interior treatments but haven’t come up with anything terribly interesting so far. In fact I can’t even really at traditional ‘wall foam’ that I would normally use, so it’ll just be stuffed full of acoustic fluff.
I do think using a firmer TPU for the cross braces would be a fantastic idea! I’ll be setting up one of the printers for TPU gaskets at some point so I’ll make a few to try out.
Yeah, I had that issue once! I added some internal ribs to a speaker back, and it was an absolute pain to firmly attach butyl rubber. I found it more effective to just have a smooth inside, use butyl rubber, and have a single brace made of a wood dowel that I glued in place after. As many different materials as you can get in there is beneficial. The more different impedances sound passes through the more the resonances are “evened” out and toned down.
I am actually am also designing an enclosure for an exciter (work project, odd use case) that needs to be quite dead sounding. Am considering experimenting with having a thicker, but more hallow wall and filling the inside with sand or some material. Will let you know how that goes; that could be an option too!
How Brad manages to beat the ‘big’ established companies (in this case, Madisound, Cinergy, and Solen too but that’s international) in shipping stuff across the country never ceases to amaze me. All ordered the same day, only Brad’s stuff is here. Eight more MAC-05s in hand for less than the cost of a pair of SB15CACs. Thank you @Hifiside!
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