iOS 5 iPhone update Ringtones won't sync

I'm trying to make a ringtone and when I go to sync on my 4s it keeps telling me the duration is too long when it's only 30 seconds long. I whittled it down to 20 seconds, then 15 seconds, then 12 seconds and nothing is working. Help?

Cheers mate, I saw trough some videos and forums looking for a solution. Yours was the only that worked for me. Thanks