The Ultima are in the high transparency, low distortion, high accuracy design.
Two-way, stand-mounted loudspeaker with rear-facing reflex port and second tweeter.
Drive-units: 1.1″ fabric-dome tweeter, 0.75″ rear tweeter, two 5″ metal-cone bass/midrange drivers.
Measured crossover frequency: 2.3kHz.
Frequency response: 70Hz-15kHz, ±1dB of target curve; -10dB at 39Hz (2-pi anechoic measurement).
Nominal impedance: 6 ohms, 4 ohms minimum.
Sensitivity: 87dB/W/m.
An interesting chat.
https://www.audiocircle.com/index.php?topic=167016.0
These are great speakers with aluminium cheeks and stand. The most expensive spec when introduced. All drivers, etc working and in good condition. Frames for covers supplied but no cloth.