Have considered lots of iterations of transmission line speaker designs over the years.  Several attempts, including an unwieldy but excellent sounding 12" guitar driver experiment have been fun to tinker with.  But it's lock-down, I've been bored for weeks and have been hoarding audio gear for ++aeons.

So, using the excuse of learning a bit more about CAD, generating some 3D printable snail shaped transmission-line speakers is the present attempt to avoid cabin fever.

The ingredients are:

• Lots of coffee
• A pair of KEF Uni-Q satellite speakers (from a set of 5 almost identical units)
• Fusion 360
• A 3D printer
• Time

Thus far, the progress has been to understand roughly what the drivers are and faff about with Fusion 360 to generate the enclosures.

The drivers are - KEF 8900-6090+Q.  Which Room EQ Wizard usefully showed to have a 175 Hz resonance.  They do have a built in crossover, which can be modded to open up the bass a bit (short out the input capacitor).  As there's no plan of putting much power through them, this should be OK, and a transmission line should limit cone excursion a bit around resonance too.

The snail shell was assisted greatly with the Equation Driven Curve app.  It's great, even if the coordinates flip about a bit.  It took ages to finally generate the shape.  Essentially involved offsetting a line 0.1 mm from an exponential spiral, then extruding the shape and rounding the edges with a variable radius fillet.  Then using the shell command to open it up and extruding through the bass to make half of a snail shell.  All joined together by offsetting the outside surface to thicken it and get rid of the gap.  Keeping it small enough to fit on a printer platform while allowing a large enough opening to later design and attach the speaker was time consuming.  The results are the first renders in the project's pictures.