Tips for building speakers in acoustic waste pipe that I wish I'd known first time

I've experimented with the pipe builds for a couple of years now, mostly focusing on wall-mounted units. When I scaled down to desktop monitors, I found that a 40mm pipe diameter really hit a sweet spot for me regarding resonance. I was initially surprised how clean the midrange became once I started tweaking the internal volume rather than just looking at the port tuning.

For mounting, I agree that the factory socket seals are clever. I found that while they work for positioning, sometimes they can introduce a bit too much dampening on the high end if you aren't careful. For me, I supplemented those connections with small custom brackets and a flexible silicone glue to secure the driver to the baffle inside. This kept the seal functional while allowing me to tighten the driver mounting securely. My biggest challenge was dealing with the low end when these small speakers sat on a desk. Even with proper tuning, the bass often just felt thin. I ended up adding a small powered subwoofer near the listening position. It made a massive difference in giving the whole system a much fuller sound without me having to overcompensate or try to fix the acoustics inside the Geberit sections themselves.

The thing that fixed my builds was a proper pipe cutter instead of a hacksaw. My first pair had ends cut by hand and they were never square, so the baffles sat at a slight angle and the sockets never seated evenly. With a ratcheting cutter every joint came out clean and square, and suddenly the friction fit method worked as well as everyone says it does. Also worth a try if your cut ends look rough: a light sand of the chamfer before assembly.

Tried something similar with a single build last winter and the thing that surprised me was how hollow the pipe sounded til I lined the inside. A couple of loose wraps of wadding stuck to the inner wall killed that empty tube ring straight away, made the whole thing feel more like a proper cabinet. Did you find the sand base was enough on its own or did you line yours too? Also curious how you routed the wire out, I ended up drilling thru the back socket and it was a bit of a faff to seal.

I always found that even if the internal tuning was perfect, a poor driver seal could mess up the whole output. Back when I was doing wood boxes, I made sure to use some sort of gasket around the speaker mounting ring. It stops air from leaking and, more importantly, stops the vibration from traveling right through the baffle and into the rest of the pipe structure. Are you running anything like that between the driver and the polypropylene? Since the pipe is plastic, I worry about the resonance from the cone flexing right into the whole thing.

Update: I finally got my hands on a ratcheting cutter as suggested. It made a massive difference compared to the hacksaw I was using. My previous joints were never square and the baffles looked rough. Now every joint is clean and flush, which lets the friction fit exactly as it shold.