The model includes four drivers in a three-channel system with a bass reflex. B1 uses one D50 (proprietary) midrange driver with a frequency range from 900 Hz to 4kHz, for a larger range, one D26 high-frequency driver is used. For frequencies below 900 Hz, B1 uses two C125 midrange (proprietary) speakers, one mounted on the front wall and one on the back wall of the housing. These two dynamics are connected from the inside to suppress the opposing force.