I use mine a lot at Nursing Home shows and private parties up to 100 or so people. The bottom end is quite surprising. I would think that if a job is large enough to warrant going to the trouble of using a sub, then you would want to use a larger p.a. anyway.
However it would be simple enough to hook up a powered sub (with built-in crossover) from the Channel 5 sends, or from a seperate mixer.
DonM