I've got Guitar Hero: World Tour. Do you have it? I have it for my Wii. If yes, then you'll know some of the pads (the red pad especially) doesn't always pick up the hits. You have to hit it harder than the rest. I didn't like this.
As I soon began playing most songs in Expert mode (thaaaaat's right), I also found the orange pad (the cymbol) also had to be hit quite hard.
So, I did a bit of research. Google was my friend.
This is a known fault with the drum kit, and as such - a free solution is provided (under warranty anyway)!
http://guitarhero.custhelp.com/cgi-bin/guitarhero.cfg/php/enduser/std_adp.php?p_faqid=21748&p_sid=HCNFwPCj&p_lva=23199
Contact them, stating the problem you're having with the drums. They'll ask you to do a few checks but once you confirm the problem, they'll send you a MIDI-USB cable for the drums to be connected to your PC/Laptop. It can take 4-6 WEEKS they said but I got mine in a matter of days!
I downloaded the software, followed the instructions, adjusted my sensitivity, and voila! Perfect hits every time!
Guitar Hero: World Tour - Great game, great support.
Digiman out