Bassbox Pro recommends 2.354 cubic feet net tuned to 23.6 Hz for a smooth frequency response curve (i.e. High Fidelity). Oddly WinISD recommends 3.812 cubic feet net tuned to 22.17 Hz. Regardless, that is my main complaint about JL Audio because one has to build their enclosures bigger and tune them lower in order to get rid of that 50 Hz boomy sound that the JL Recommended enclosures tend to produce. Ive started to call it the JL Audio hump.