The 4645C is based on the 2242H low frequency transducer, a device capable of sustained power input of 800 watts. In this system, the enclosure tuning is at 25 Hz, which means that cone excursion is minimal at that frequency, even for very high power input. As a result, the system can deliver very high levels of fundamental output in that range. Under half-space (single boundary) mounting conditions, response is -10 dB at 18 Hz.