How do I politely ask my parents to let me quit? Please help!!?

Ok so I do band and I absolutely HATE it. I've been doing it for almost four years and I used to get into all the top bands. Now, I dislike practicing, lessons, carrying my instrument around, 'A' period, and so on. My parents are convinced I still enjoy it, and both my siblings do it and LOVE it. How am I supposed to ask to drop out? Pleeaasee help me! I'd really appreciate it!