G-Lab GLA-BWW-1 Bass Wah Effect Pedal Resonance frequencies range switch causes moving the whole resonance frequencies range: LOW position - wah-wah enables higher influence on the low (bass guitar) frequencies In HI position it boosts mid/high frequencies what makes the wah-wah effect deeper Quality factor of the resonance circuit switch, HIGH position - increases resonance signal level especially of low frequencies what intensifies the wah-wah effect.