1. one subwoofer...Power Sound Audio Sealed 15" providing bass below 50hz
2. used for supplemental bass...tried replacement but didn't sound nearly as good
3. Salk Veracity ST...each has dual Seas 6" mid woofers with transmission line...strong, toneful output down to 40hz in my room
4. Room...30'x 40' x 10' ceilings, open concept, tile floors, drywall, glass door walls, furniture, throw rugs....no sound absorption panels
5. Amplifier....DAC 2Cherry
My experience is that there isn't much "tone" below 40hz but a lot of "feel, ambience, and the sensation of realism". With my room being so large, the Salks needed reinforcement. They provide the tone, the PSA S1500 provides the impact.