Before auditioning different lo-freq cut-off points (I recommend the 50Hz also) you should find a reasonably intelligent location for the sub. . . . . .
Assuming you have only one sub (best IMO, as long as you can keep the x-over point below 100Hz) AND assuming the sub has no phase adjustment, the best method is to place the sub at your listening position, and then listen to program material from different locations in the room to find the best "final resting place" for the sub ;-) Try listening from these positions:
>Each corner of the room
>Smack between the main speakers
>Different positions along the four walls, but particularly the one behind the speakers.
>Right behind the listening position
One of them should provide the strongest and most seamless response in your room. Place the sub there.
.
Assuming you have only one sub (best IMO, as long as you can keep the x-over point below 100Hz) AND assuming the sub has no phase adjustment, the best method is to place the sub at your listening position, and then listen to program material from different locations in the room to find the best "final resting place" for the sub ;-) Try listening from these positions:
>Each corner of the room
>Smack between the main speakers
>Different positions along the four walls, but particularly the one behind the speakers.
>Right behind the listening position
One of them should provide the strongest and most seamless response in your room. Place the sub there.
.