Any Music, Playstation, GD-ROM (Dreamcast), or CD-ROM (Computer, any format) will make monsters at the shrine. DVD and CD-I discs do not work if you are playing on a PlayStation (any model) or PS2 (any Model).
DVDs do work if you play the game on a PS3.
Blue-bottomed PS2 discs will work, but the silver-bottomed DVD PS2 discs will not work.
Blank, unformatted CDs will not produce monsters. There are reports of certain brands of formatted CDs producing monsters.