I made the layout with interface builder already. Basically i have 6 buttons labeled E,A,D,G,B,E for each string on guitar. When i press a button i want it to play the desired note. I have figured out how to link the buttons to the sounds. The problem is that the sounds are originally in a .midi format. I am not sure how to get the application to use quicktime to play the midi files. I converted them to .aif and the files each were about 24 megabytes. That makes the application way too huge. Each midi file is about 4kb. So, How do i make my program use quicktime to play a midi file? I am just using a standard cocoa template.