Our new HST-18 mkIII is the result of years of pursuing perfection in the lower octaves of audio reproduction. Playing extremely deep and loud with the ability to sound superb in a very small enclosure is what the HST18 mkIII is all about. Our new driver reaches a 0.707 alignment in 3.7 ft^3 sealed with a vented alignment suggestion of 8 ft^3 tuned to 18 Hz. For extremely deep reproduction below 20 Hz our new driver has a modified motor which allows for 40 mm of one-way linear travel. Multiple faraday rings inside the 250 mm diameter motor improve impulse response over other designs.