Question Why is there a hole on the face of the Perform-V under the 3 button  Answer This is where the RoomSense microphone is located. If you are using a preset with Harmony or HardTune and you are not using the Aux input to guide your key/scale, the RoomSense microphone can pickup chords from a nearby instrument to determine the key/scale to be applied to your voice.  Or, if you do not have a microphone, you can plug headphones into your Perform-V and just use the RoomSense microphone.