Answer

When measuring the maximum SPL of a loudspeaker or subwoofer, the peak level is taken into account, but not the QUALITY of the sound at that volume. While the KW181 does a great job at performing clearly and loudly, in order to achieve maximum SPL it is well into DSP limiting and protection, and may not sound as clear at high volumes as it does at lower volumes. With the larger amplifier and new woofer in the KS118, there is significantly more headroom and dynamic clarity before the onboard limiter and protection circuitry are activated, giving you a clearer, fuller sound at higher SPLs than you could previously achieve with the KW181