According to Stereophile's measurements its's fabulously efficient - 94.5 sensitivity BUT: "it needs to be used with an amplifier that can deliver high current into low impedances. Not only are there two minima in the bass of less than 2
ohms, and another of less than 3 ohms in the mid-treble, but there is an amplifier-crushing combination of 3.3 ohms magnitude and 60 degrees capacitive phase angle at 20Hz." So let's bear this in mind when making suggestions. Normally tube amps would be considered as well, with that sensitivity but that doesn't appear to be wise here.