The M2 looks great...but where can I put my active crossover in an all-digital system ? Right now it's between the preamp and power amp.
That would be a problem with the M2. It has a tape loop, but only in the digital domain (TosLink in and out).
But if it was a DSP x-over, it might have a chance. At MSB's website, they explain how their DSP x-over goes before the DAC. DEQX, TACT and Behold all have these as well and one would think they go before the DAC.....
How about not using the crossover?
Not recommended - all speakers need them. The latest research shows why and it's called Doppler Distortion. This effect explains why full-range drivers come up short - in the end - compared to the best-designed multi-ways.
And they don't screw up the souind?