Funzioni avanzate di bass management: mi date una mano ad orientarmi?

Il Meridian G68 - che adesso è in Italia ad attendermi - ha funzioni avanzate di bass management che non so se ben capisco:
le mie casse sono in signature e come soglie inferiori di frequenza vanno dai 100hz delle posteriori ai 55hz del centrale e fino ai 38hz delle 926.
Si possono gestire tre impostazioni diverse a seconda di music, logic e cinema 5.1.
Con la mia configurazione, come devo impostare le funzioni che seguono?

http://img122.exs.cx/img122/515/screen036vu.jpg

You can select the subwoofer configuration, and whether the
centre speaker is used in the layout, in the Speaker usage
section. Information about your choice will be displayed below the
Speaker usage section.

Capisco che posso dirgli che uso il centrale oppure no per la gestione dei bassi? O è il subwoofer che viene visto come center speaker??

If you include only one subwoofer in the layout, and you have
specified your main speakers as Small, the subwoofer will be used
for the bass and LFE.
If the main speakers are Large the Front
subwoofer option allows you to choose whether the subwoofer
handles just the LFE, all the bass (Bass-neutral), or the bass
together with the main speakers (Bass-heavy).

E qui mi è chiaro

If you include two or more subwoofers in the layout, irrespective of
the size of the main speakers the subwoofers will handle the bass
and LFE for the system.

Ok

The Crossover option allows you to set the crossover frequency
for the subwoofers. This is disabled if the subwoofers are only
handling the LFE. The Meridian digital surround controllers provide
very high-quality crossovers for the subwoofers, and for best results
you should use these instead of the subwoofer’s crossover. To do
this set the subwoofer Width property to Narrow, and remove
any crossover in the subwoofer or set it to the highest setting (eg
200Hz). If you cannot do this set the subwoofer Width property to
Wide to switch off the digital surround controller’s crossover and
use Sine/Sub mode to match the subwoofer’s crossover frequency.

BOH

The LFE low pass filter option sets the low-pass filter for the LFE
channel, for the Music and 5.1 Movie speaker layouts.

Che vuol dire?

Click the Reset button to reset the crossover and low-pass filter to
recommended values in all layouts.

In addition, a THX settings panel allows you to specify that your
subwoofers are THX Ultra2 approved, and select Boundary
gain compensation to reduce bass levels if listeners are close
to a wall. Click the THX Defaults button to set the crossover and
low-pass filter to 80Hz in all layouts, as recommended by THX.

E se non arrivo a 20hz con il mio sub? immagino di non flaggare la casella, ma cosa succede?

Grazie in anticipo a chi vorrà aiutarmi