The FredArray incorporates a ten driver midwoofer line array with a point source tweeter. The ten midwoofers are 5.25" Silver Flutes with cast metal frames and treated wool cones. After trying several tweeters I selected an MCM 1" titanium dome driver. Each enclosure is 72" high, 10" wide, 14" deep. The enclosures are rear-ported with two 4" ports. F3 is in the low 50's. Sensitivity will be about 95dB. The nominal impedance is a tube-friendly 9 ohms.