I was committed to using a Fostex polymer dome tweeter in order to match the replacement tweeters I had previously installed in my front speakers (two-way speakers from an old three-piece DBX Soundfield 3 x 2 RS Plus speaker system). The Fostex tweeters are 4 ohms, with a frequency response of 2-20 khz, an efficiency of 91 db/1w/1m, and rated for 35w RMS. I purchased the tweeters on eBay, but PE (Parts Express) sells many excellent tweeters with similar specifications.

I looked for a 5" woofer/midrange that would complement the tweeters and was attracted to the Westra KF-130-1304, which was available at a buyout price from PE. The Westra driver is very efficient at 91 db/2.83v/1m, has a smooth frequency response from 200-4,000 hz, and it's rated at 4 ohms impedance and 20w RMS.