The ML's are not all that inefficient, they are rated 89dB/watt at 1M, which is about average these days. But they DO have a low impedence dip of 1.5 ohms. This drives most amplifiers just wild. Tubes suffer most, as their transformered output is only designed for a level-impedence load, they have taps for 8 ohms, 4 ohms, etc. At other impedences, and into reactive or capacitive loads, (and the ML's certainly qualify for THAT), all tube amplifiers and some solid state amplifiers distort and/or modify their frequency response output. One's impression of "cold" or "warm" is actually caused by the modificacion of the frequency response plus added harmonic distortion, lots of it in the case of tubes, like 5% or 10%, as the amp tries to drive the difficult load that the ML's present. The SOLUTION to this situation is to purchase an amplifier that has large current and voltage capability at low impedences, and that has enough power to drive the ML's to a reasonable level at the same time. To play the ML's at 103dB, one needs 256 watts of amplification (it's a simple mathematical calculation). Then it's a question of selecting an amplifier that provides this power into the ML SL3's 4 ohm nominal impedence AND can drive a 1 ohm load to the approximately 800 watts needed to provide a flat-bandwidth output. There are many good solutions, some for even under $1000. Not to mention brands here, feel free to email for some suggestions.
