If your receiver (or processor) does not perform "bass separation", then both speakers and sub will receive the full spectrum. The sub is equipped with a cross-over that will filter-out all frequencies above the configured threshold (there is "slope" to allow blending with the main speakers).

The M2v2 are starting to curve down aroung 75hz. Setting the sub to 80hz would naturally blend nicely. Actually, the manual should be suggesting something.

See Mojo's signature