I have a pair of ML Montis. The impedance curve is quite complex, going from c.3k real at DC, to capacitive, to inductive at the crossover (c. 340Hz) to capacitive, to entirely real at c. 20kHz (0.9ohms) to inductive.
Over most of the audio frequency range the impedance "waves" around 4 ohms.
I use several amplifiers to drive these speakers, including a pair of Rogue M180s, a Hypex Ncore400 and a Benchmark AHB2.
All three amps are stable into the load- all reproduce decent 1kHz square wave outputs.The Rogues, used in the 4 ohm tap mode, have an output impedance looks that like about 0.3 ohms in series with an inductor, and there is a measurable and simulatable loss at 20kHz, but it only amounts to about 3dB, although very low impedance speaker interconnects are advisable. With the Benchmark the HF loss is substantially less, but surprisingly little difference can be heard between the two due to the altered frequency response.
The Ncore amp sounds rolled off in comparison to the other two, but doesn't measure significantly differently, which is surprising.
Neither the Benchmark nor the Ncore produce any audible high order harmonics in the audio band. The Rogues, on the other hand DO produce audible low order harmonics. The Rogues can be played subjectively louder than the Benchmark despite their having nearly identical power ratings into 4 ohms (180W vs 190W) with the Rogues producing several orders of magnitude higher distortion at the rated outputs.
Overall I have settled on the Benchmark as my amp of choice with the MLs.
Over most of the audio frequency range the impedance "waves" around 4 ohms.
I use several amplifiers to drive these speakers, including a pair of Rogue M180s, a Hypex Ncore400 and a Benchmark AHB2.
All three amps are stable into the load- all reproduce decent 1kHz square wave outputs.The Rogues, used in the 4 ohm tap mode, have an output impedance looks that like about 0.3 ohms in series with an inductor, and there is a measurable and simulatable loss at 20kHz, but it only amounts to about 3dB, although very low impedance speaker interconnects are advisable. With the Benchmark the HF loss is substantially less, but surprisingly little difference can be heard between the two due to the altered frequency response.
The Ncore amp sounds rolled off in comparison to the other two, but doesn't measure significantly differently, which is surprising.
Neither the Benchmark nor the Ncore produce any audible high order harmonics in the audio band. The Rogues, on the other hand DO produce audible low order harmonics. The Rogues can be played subjectively louder than the Benchmark despite their having nearly identical power ratings into 4 ohms (180W vs 190W) with the Rogues producing several orders of magnitude higher distortion at the rated outputs.
Overall I have settled on the Benchmark as my amp of choice with the MLs.