Woofers & Piezos

Each driver pair is "one side" left or right, do not under any circumstances connect left and right outputs to two drivers mounted in the same enclosure volume as it could have some nasty and weird side effects when the bass output isn't perfect mono. (Saturnus)

Sealing Piezos

• Must be non-acidic (Saturnus) low modulus, neutral cure silicone.
• Don't ever use vinegar based acrylic sealer as the fumes will eat the speaker cones slowly. (Saturnus)
• Fill on the grooves on the backside of the horn first then make thick circular rings of silicone roughly 1cm apart also on the back part of the horn. Check that the driver bit hasn't come loose. If it has, glue it into place. Cover the back of the driver bit with an even coat of silicone. (Saturnus)
• But the siliconing of piezos, I always recommend doing that. They always improve a lot in sound when that is done. I always take apart the driver section and glue it back into place. More often than not the serious vibrations it is subjected to inside the cabinet will shake apart a low cost piezo only assembled with 2 small screws. (Saturnus)

Glueing

• Speaker magnets to plywood: "JB Weld" in the US or "Liquid Metal" in Europe, basically 2 pack epoxy. (steveeboy)
• Front of speakers and grills to plywood: low modulus, neutral cure silicone. GE Silicone II in the US. (steveeboy)