Acoustic Research AR-3a tweeter backing plate and centering ring for Fountek, Neo CD 3.0 ribbon tweeter

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These parts are designed to center and secure a Fountek NEO CD 3.0 ribbon tweeter in the factory hole of an Acoustic Research AR-3a loudspeaker. You will need to cut four grooves in the factory hole for the M4 screws to clear and remove one of the three original screw plates. Then use four M4 screws and four nuts to secure the tweeter to the speaker enclosure. The ring centers the tweeter and makes it easy to mark the locations to cut the grooves. The back plate goes into the cabinet behind the tweeter and clamps the tweeter in place. The cabinet is sandwiched in between the tweeter and backing plate. You will also need long lead wires so that either you can connect the tweeter outside the cabinet at one end or quick disconnects inside the cabinet. In my case, I went with the latter. The wires must pass through the backing plate opening. There is ample room inside the cabinet to attach the nuts and put a wrench in place to tighten down the screws. You will want to use thread locker (low strength) or lock washers to keep the fasteners from loosening. The back of the Fountek tweeter has a sealing pad, but since the tweeter has a smaller outer diameter than the original, I suggest using cabinet sealer on the opening surfaces and the original tweeter screw holes. As to crossover modifications, I substituted the original tweeter crossover cap for a 2.2uf 400V Solen poly and a 0.45mH 18awg air core inductor crossover coil by combining one 0.05mH and one 0.40mH Jansen Audio coils and hot glued the assemblies to the back of the tweeters. Otherwise the original factory crossover design remains the same. All I did was replace the original capacitors with new poly ones and replaced both pots with new ones which work as they're supposed to. One final modification I did was replace the original speaker wire terminals with 5-way binding posts. There's no drilling required but you will need to replace the ring terminal on the blue ground with a slightly larger diameter one to fit the post. The remaining ring terminals should fit.