This is an extremely boring thing to write about, but hopefully it will save someone some annoyance. JBL’s Control 25 and 28 speakers come with a neat, simple plate-and-stick “Invisiball” mounting system, designed to mount the speakers on vertical walls. They also sell an adapter to attach them to the ceiling instead, where the “stick” of the normal adapter is replaced by a longer, offset stick enabling vertical mounting. These adapters require that you have the original wall plates, but the used speakers I bought were missing them, and new ones cost more than I paid for the speakers, so I wanted to figure out how to mount them some other way.
For the search engines among you, the ceiling adapters are part number MTC-2825CM, and the original wall mounts are 179-00002-00 and 179-00002-01, in white and black respectively.
The ceiling mounts I had came with an extra cone-shaped, dual-threaded adapter that I couldn’t find a spec for:
I found a spec sheet for the ceiling mounts, which tells me that the end of the mounting rod has an imperial 7/16″, 20tpi thread (really??). But the one on the blunt end of the cone was a mystery that didn’t fit any of the bolts I had (which were mostly for bikes, so all too small). I took some measurements and guessed that it might be a 3/8, 16tpi, given that the other threads were all imperial so I ordered some nuts… which were wrong. I remeasured and popped to my local DIY store, where I verified that it is actually standard metric 10mm thread. So we have a revolting combination of imperial and metric units. Blech. At least it looks neat!
That finally screwed down, I designed (in Autodesk Fusion) a ceiling mount that this threaded end could fit into that I could 3D print. It looks much nicer than the stock mounting plate, and the screw holes are designed to take nice stainless steel Allen bolts. Because it’s designed to mount vertically and bolted to the ceiling, the plastic will be mostly in compression, a direction that’s nice and strong for printed parts, though the speakers only weigh 3kg each. I printed it with a generic white PLA Meta filament that only took 70 mins to print two of my design on my Bambu P1S and feels really strong even with only a 15% infill (though with 5 walls). You can find the model on Thingiverse and Makerworld.
