that is from the mpyre forumI just ran a quick and dirty simulation and it looks like a .7 ft/3 vented box tuned to ~33hz. That will get you response that is only down .2 db at 2.5-3 khz with an F3 of ~36hz. A sealed box will have almost identical 'roll off' at the higher frequencies as the vented one but will have an F3 of ~78hz if it is .2 ft/3...although that may be a bit difficult to build We weren't really anticipating too many people putting the midbass in an enclosure...