Soundfield introduced a new version of my M2 speaker at RMAF 2013 (though there is already one pair in use with a customer).
They are designed specifically for lower power, low NFB tube amplifiers with high output impedance (all?). That means not only is the sensitivity high (>100db/watt, measurable/verifiable), but the impedance is benign.
Specifications are:
8" 2 way, with super and rear tweeter options. Woofer is actively driven (<700hz) by 150w rms AB amplifier mounted in stand.
>700hz, a planar magnetic horn loaded ribbon midtweeter is passively driven by the main system amplifier. Recommended power is 1-30 watts.
FR 40Hz-19Khz +/-3db, sealed box.
Dimensions/weight: 20" H x 10" W x 10" D, 32 lbs
Stand: 24" H x 11" W x 12" D (base), 32 lbs
Price: $2400/pr as shown (Cherry veneer). This is for speakers/stands system.


