Welles used techniques from radio like overlapping dialogue. The scene in which characters sing "Oh, Mr. Kane" was especially complicated and required mixing several soundtracks together. He also used different "sound perspectives" to create the illusion of distances, such as in scenes at Xanadu where characters speak to each other at far distances. Welles experimented with sound in post-production, creating audio montages, and chose to create all of the sound effects for the film instead of using RKO's library of sound effects.