A true leader knows when to hold 'em, and knows when to fold 'em, just like the bard's song says.
To claim Bardic armor set, you first need to find the Arcade Console in the Bizarre Interior at Quarex's Museum. After realizing you cannot beat this arcade game, you must find Bard's Tale IV: Tips 'N Tricks. You'll find this book at Denver Airport. It's safely stored in a broken toaster. With the book, you'll now be able to beat the arcade game. Shortly after, a radio broadcast will inform you that a crate is waiting for you at Ranger HQ. The complete Bardic set will be inside.