Fourth show means Black Sabbath Vol 4 which is the consensus favorite of the Searching For The Sound crew. A whole new guitar tone is explored as the boys debate whether this was the first grunge record. Neil Young may be the godfather of grunge but Ozzy and company were patient zero. John teases the Sabbath/Pink Floyd/Wizard of Oz moment he experienced with Snyder and they all go through "Changes" at some point during this episode.