What are your exact settings for volume and low pass filter on your SVS sub?

With my ATC SCM40s—passive—I’ve set the volume on my SB3000s at 20 and the low pass filter at 58. The speakers go down to 48hz at -6db.

I have no frame of reference and feel insecure about my selections. It would be great to hear from other people about what works for them, although I know that it’s always apples and oranges because of the room factor, the amp, the different speakers, and all the rest.