I can't tell you which one is more quiet, the Bender or White Knuckle. Just that they have a different tone to them. Bender has a throaty more low tone, where White Knuckle (QC1) has a tinny tone to it, kind of like a Vance & Hines street bike sound. I will be running the QC1 on trail this year, and if there is someone who has a bender system, it would be nice to pair them up side by side.