Just consider how much a difference of 9dB is. I read about SPL in detail on expert websites.
6dB difference means twice the amplitude of the sound wave.
Double performance (wattage) just renders +3dB.
That means if you use a pair of Bose S1Pro (which means double wattage), the SPL inceases from 103dB to 106dB and still only leads to half of the amplitude of a single L1 Compact (112dB).