Hey guys. Even though I've been a forum member for seven years, this is my first post!

In about four years, I'll be building a dedicated music listening room. My endgame will be Sierra RAAL Towers with dual Rhythmik subwoofers, proper room treatment, etc., etc., but for now, I am a proud Sierra-2 owner in a simple small room.

Over the next four years, I will be moving various times and will mostly be listening in smaller rooms. Currently, my system is struggling with the low end. Without a subwoofer, the Sierra-2s do not have sufficient bass output in my room for music. With my HSU Research STF-1 subwoofer (8-inch), the bass often becomes boomy.

Since I'll move a few times over the next four years, if I spent around $500 to even out the low end, where would my $500 be best spent? Acoustical treatment? Another STF-1? A different sub, like the Rhythmik L12?

Appreciate any answers. The Sierras sound excellent running by themselves, but when I try to fill out any bass, I always run into this boomy issue.