In the "Soundboard Filter Challenge" by Sir Geybin, he engages in a fun and humorous game using soundboard effects to alter his voice and add comedic flair to conversations or scenarios. The challenge involves reacting to different sound effects, leading to entertaining and unpredictable moments. Geybin showcases his creativity and quick thinking as he navigates the challenge, creating a lively atmosphere filled with laughter. The video highlights his playful personality and the joy of experimenting with sound in a unique way.