Tips and Hints by Stephen Fretz 1. Do Not, under any circumstances, attempt to drive the speaker below its free air (Fs) resonance point. Normally, when designing an enclosure, the goal is to maximize the usable bass of the woofer, consistent with decently flat frequency response. If you do this with a full range driver you will get unbearably muddy sound. If in doubt, start rolling off the bass above Fs, and steeper rather than shallower. 2. Dr. Gizmo is right: at the microscopic power levels involved with these things, less (in terms of wiring and connectors) does indeed seem to be more. 20 gauge un-insulated silver wire seems to work great - the el cheapo female banana plugs from Radio shack (the ones you hammer into a 5/8th" hole) are better than expensive giant gold plated ones. Silver or copper foil probably works even better, but I haven't tried it yet. And remember that air is the best insulator: inside a speaker you should be able to arrange the wires so they don't come near each other: paper masking tape will work wonders to make it permanent. 3. Remember that all enclosure material have a sonic signature. Ask yourself is there is a reason why, apart from tradition, full range speakers are usually put in birch (or luaun, if we're in Japan) plywood enclosures, rather than MDF. by Frenchy 1. Concrete is an excellent horn construction material Just make a mould and pour it. Have made them to 20" mouth. No coloration or ringing, but you don't want to move house too often. The go we found was to use a stone and cement mix, no sand. It gives a really good surface finish and is very dense. The upper mid horns we constructed are octagonal outside and a tractrix flare to a 12" mouth. A 3/8 alum plate is used to mount the compression driver which is attached by bolts set in the concrete when poured and vibrated. The results are excellent! They are circular in cross section naturally. Top