Let this graph speak for itself (blue line)
"The ES250P’s close-miked response, normalized to the level at 80 Hz, indicates that the lower –3-dB point is at 24 Hz and the –6-dB point is at 22 Hz. The upper –3-dB point is at 113 Hz using the LFE input.—MJP"
While not earth shaking, still very competent sub for the money and small to medium sized rooms.
get it while it lasts
http://www.jbl.com/ES250PBK.html