I have been trying out a Forecefield 3 sub and think it is a great product but want a bit more bass presence in my system.

So I am assessing if I simply upgrade to the Forcefield 4 or buy another Forcefield 3.

Trying to purchase for the future as well...

Currently I will be using the sub in my family room system which is a mid sized room that uses a 5.1 array of small speakers.

Next year I will be using the sub in a media room with a 7.1 array array of large main speakers and mid sized surrounds and center speaker. (Goldenear 50 series).

What would be Goldenears advice?

We always recommend two subs over one for best in room bass performance.

Hope this helps.

would a pair of Forcefield 3s be a little small for my future application (vs a pair of force field 4s) due to the larger speaker size?

Budget options are buy another ff3 now or buy a ff4 now and another ff4 next year...

If the room is quite large, two ForceField 4's would do a better job of pressurizing the room at higher volumes.