At the page of Real-time preview:
"Enable: This checkbox contains a checkmark by default Enable, which enables the effect.
Remove the checkmark Enable to disable the effect (also known as bypassing the effect). Disabling makes the audio play as if the effect was closed and the effect's controls will no longer change the audio. Disabling and enabling is a convenient way to compare the "dry" (non-affected) sound with the "wet" (affected) sound while it plays in real time."
What is the "effect"?