The active studio subwoofer S10.4 builds on KRK's tradition of sound accuracy and performance. The specially tuned glass-aramid woofer delivers tight, defined bass, while the Class-D amplifier significantly enhances transient response, control, and punch. The selectable crossover frequency in four positions makes it easy to adjust the subwoofer settings to match your existing monitors. When you pair the S10.4 with KRK or other studio monitors, you achieve an optimized listening and mixing experience with an extended low-frequency range, while the exclusive bypass function allows the monitors to operate at full capacity without turning off the subwoofer.