At least try 40hz. You cannot go by specs, it’s actual performance in that particular space. ’Real’ bass extension takes more than a single 10".
I think even 40hz crossover is too low, my subs (1 office with smaller wharfdales, 1 home theater with dbx 100’s) both do better at 80hz.
Office, I just add enough to keep the system from sounding ’small’. Only aware of it when I turn it off.
Home Theater, it’s to give some ’Dinosaur Stomp’, i.e. Jurassic Park, Black Hawk Down, not for music extension, the dbx soundfield 100’s do well enough on their own.
If you buy an inexpensive sound meter, it will give you good info. It doesn’t need to be perfectly calibrated, just shows output of specific frequencies relative to other frequencies. This one, on a tripod, ear height, listening position helped me a lot
this test cd has separate tracks for each frequency, and they are 1 minute long (longer than needed, but not too annoyingly short).