HalM

The cellular telephone construction industry has suppliers everywhere such as Kenwood, Tessco, GrayBar, etc. One of the most commonplace items is a Universal Weatherproofing Kit, "Type WK-U." This kit has one roll of two-inch wide, thick vinyl electrical tape, two rolls of 3/4-inch vinyl insulating tape, and six rolls of butyl rubber between wax paper separators. All this for a couple of bucks. What is usually done with this stuff is to cover coax connectors on "flexible" hard lines from 1/2" diameter to 2-1/4" diameter. The plastic horns on my newly-acquired Forte-II's and Chorus-II's are resonant somewhere in the audio spectrum. I guess if they were made out of concrete I might be able to keep the buzz down, but plastic they are, and buzz they do. Using a second generation H-P audio oscillator going into the audio chain at 0.1 volts P-P is a great way to sweep cabinets. If they are going to push out all the speaker screws and walk around the floor like an old washing machine, an audio oscillator will find out how soon. However, back to the plastic horns. Yes, they buzz. Using the butyl rubber portion of the WK-U kits, pieces of rubber about three-inches square are cut, leaving one side of the wax paper attached to the butyl so it doesn't get to be too bad a chocolate mess. The squares are simply laid on to the plastic and also on to the flat metal magnet surfaces. Next, the 3/4" tape covers the outside of the butyl rubber (which is naturally sticky). The finishing layer is the two-inch-wide, thick electrical tape, over the 3/4-inch-wide tape, which imparts a smoother finish. With just the thin diameter tape covering, fingers can be used to squish-in the butyl into corners where the ribs are, etcetera. One WK-U will really do a midrange squawker well, and the left-over material can goon the woofer and tweeter magnets to break up the hard surfaces, and even using some of the material on the bare wood inside the cabinet will affect its vibration reaction. Lastly, and this is an old Klipsch trick, is to put a board across the speaker stand bottom, seal the gasket surfaces with RTV, drill a filler hole in the side and fill with pool filter sand, tamping it down by hitting the bottom slab lightly with a dead-blow hammer. The hammer really helps because the bases will accommodate thirty percent more sand by volume if reasonably tamped. Hal

Steve Phillips from Klipsch just e-mailed a corrected crossover schematic. The squawker network's 1.5 uF capacitor connects to the Positive Polarity Input buss, not the negative as was previously published. I don't know how to paste the diagram hereon.