Sub crossover freq for MMGs?

[Feanor]

BTW, just out of curiosity: What if one were to split out the signal before sending it to the pre-amp and filter it there, i.e. sending everything above 80hz to the integrated amplifer that feeds the MMGs, and sending everything under 80Hz directly to the subwoofer?
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The issue, of course, is volume control, that is, you would want a volume control ahead of the crossover device so the volumes of the amp and sub volume can be controlled together. Some degradation is inevidable, however with a decent volume control device, (in effect a preamp), the degradation is likely to be unnoticable.

My own amp, (the Bel Canto), doesn't have a "main in" either. However my MG 1.6's inherently have much less of the "loudness" problem than the MMG's, so I just set my sub to 50Hz which is just above the 1.6's roll-off in the mid/low 40's. Integration is pretty good.