I had download the code from this page
http://todbot.com/blog/2006/10/29/spooky-arduino-projects-4-and-musical-arduino/
Although the code said it play drum sound, when I connect Arduino with my CASIO CTK-6201, I can only hear piano sound...
Then, I get some demo code from internet, all I can hear is still piano sound....
I wonder it is the setup problem of the CASIO CTK-6201.
Could somebody give me some hints for it ? Is it a problem of GM of CASIO CTK-6201?