The following is a list of built-in effects in the RC-300.
- Robot—produces a robotic effect.
- Female—simulates a female voice from a male voice.
- Male—simulates a male voice from a female voice.
- GT-Bass—simulates a bass sound from guitar.
- Distortion—Natural OD, Blues OD, OD-1, Warm OD, Distortion, Modern DS, Stack, Loud, Metal Zone, 60's Fuzz