Changes

Some boosts feature additional knobs or switches. These are usually to swap out the circuits of their high-pass or low-pass filters, altering their frequency response and thus changing the distortion. For example, some may have a "fat" switch that allows more bass to pass through. Some may have additional knobs, perhaps featuring complete Bass/Mids/Treble controls. Some switches may alter dynamics, such as using compression to lower transient noise or increase sustain.