the baaj temple is a confusing puzzle... unfortunately, if you missed the special item chest in the bevelle temple, you're out of luck. it is the one place in the game where you can't revisit later. it's one of the easier ones to find, so you might have already gotten that one. most problems for the baaj temple involve the zanarkand ruins. if you return to it after you've beaten yunalesca, there will be a new "sound" pussle for you to solve. this one's pretty tricky, but it isn't impossible. this is usually the last sphere people miss. good luck!