Currently I have a 7.1 system connected to a Denon 3808 receiver. The speakers consist of Sierras for LCR and 170s for the 4 surrounds. My sub is a Hsu VTF 3.3. The crossover is set at 60 HZ for LCR, 80 HZ for the 170s, and 120 HZ for LFE soundtrack. My room is around 6000 CF.

The sub is positioned 12 feet from prime listening position and can not be moved closer. If I bought a MBM 12 it would be placed directly behind the main couch for the near field effect.

Hsu offers a mid base module for 50-80 HZ called MBM 12.

Does anyone have any experience with listening to the Sierras with a MBM 12 and another sub?

Will I notice a substantial difference in bass if I buy a MBM 12 and set the VTF 3.3 for 0-40HZ, MBM 12 at 50-80 HZ, and the remainder for the Ascends?