This is a view of the box the fan subwoofer requires. It could actually be mounted in a hole in the wall between two rooms if it weren’t for the fan noise. The box you see is a fiberglass-lined labyrinth inside, mostly needed to eliminate the whirring sound. The actual infinite baffle enclosure behind the fan is the second room itself, not the box. The box fits up against the wall and its opening into the listening room looks like a large air-conditioning grille. The fan subwoofer moves so much air that ET kept the windows open in the enclosure room to prevent any kind of restriction. How low will it really go? ET had a precision real-time analyzer showing absolutely no rolloff down to near DC! 10-20 Hz effects in film soundtracks were spectacular!