there is for me. not unless you want to change the gain knob every time you change movies or music you are playing.
If you setup the sub/s correctly, this should not be the case. Setting up the sub/s of course involves how much gain, the cutoff points, and positioning. If the problem is inherent from the source material, then there is nothing you can do about it.
Assuming you use one type of sub only:
One sub at 75 db is as loud as 2 subs at 75 db.
But you get better room response from 2 subs, better headroom which would translate to the subs amp not being taxed as much as one sub with a higher gain, resulting to less distortion.