HexiBase 3D Printed mini subwoofer, redux

As many in this forum will know, a couple of years ago youtuber HexiBase built several 3D printed subs using the Tang Band W3-1876S 3" subwoofer. I was very interested at the time, but the lengthy 3D print was a problem for me. I got the idea to make a version of his design that was hollow on the inside, so it would print much faster and I could then fill it with concrete. I got as far as making the 3D model, but then life got in the way and I all but forgot about the project.

Fast forward 6 months, and youtuber DIY Perks posted a video where he did pretty much what I had in mind (Fill a 3D printed speaker enclosure with something pourable) only using his own speaker design. He also use concrete, but plaster of paris with PV glue mixed in. This gave me the kick in the butt I needed, and I bit the bullet.

I ordered the Tang Band driver, finished my HexiBase redux design:
HexiBase subwoofer redux Hollow filled with plaster - Imgur.png


And kicked off the 3D print:
IMG_7839.jpeg


It took quite a while (39 hours), and it's far from the cleanest 3D print I ever did, but eventually it was finished:
IMG_7847.jpeg


After a test-fit to see if the driver actually fit it was time to fill the enclosure it with modelling plaster. I used the orbital sander in the background to vibrate the enclosure while pouring to convince any air-bubbles to move to the top:
IMG_7855.jpeg


And here's the sub after curing in its natural habitat:
HexiBase subwoofer redux Hollow filled with plaster - Imgur.jpg


And this is what the plaster-side looks like:
IMG_7858.jpeg


This is a temporary setup, since I don't have a 2.1 amplifier, or something similar. Not entirely sure what I'll do yet, but right now I'm investigating a Teensy-based DSP + I2S DAC. I don't have any measurements or anything, but even with this temporary setup I subjectively get a much better bass sound than with just the KEF Q150's I have.

Feel free to ask any questions you like. If there's interest I'll happily publish the CAD and STL files on printables.
 
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Looks really good!

What kind of concrete did you use and what kind of plastic filament?

I am in the process of doing something similar but three way speaker cabinets and my thought was using epoxy mixed with sand for the pouring part but i think concrete would be cheaper? maybe heavier too? I am using PLA and heard it doesn't like humidity well.
 
What’s the freq response (simulation) look like for that transmissionline?
I didn't do the simulation myself, but in his original video HexiBase showed the below graph, produced (I presume) by BassBox Pro. Note that this was made based on the driver parameters he measured himself, since the specs provided by TangBand didn't validate:
1696880961073.png


See HexiBase's video for more details:
 
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Looks really good!

What kind of concrete did you use and what kind of plastic filament?

I am in the process of doing something similar but three way speaker cabinets and my thought was using epoxy mixed with sand for the pouring part but i think concrete would be cheaper? maybe heavier too? I am using PLA and heard it doesn't like humidity well.
I printed the enclosure using the cheapest PLA I could find, just in case the print failed. The filling is Modulan 105 Modelling plaster I got from Hornbach. I got a 1.5 kg bag, which was plenty and cost just €3,39 , so definitely cheaper than epoxy :).

Not sure what the problem with PLA and humidity would be, I've never heard of that. Filament can indeed absorb moisture while still on the roll, and that can affect print quality, but other materials like PETG and (especially!) PVA suffer much more from that. But once it's printed humidity is really not an issue anymore. Filling the box with modelling plaster also went well. Obviously you need to ensure your print is watertight, but that goes for every material, not just PLA.
 
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