i myself am a saxophone player.. and u can do multiphonics... just play a low note, get an overtone, let it go back down to the low note then try to find the split in the middle. you should be able to play the high overtone and hear the low note really soft. hope that helps

* forgot to mention i have played the clarinet for 4years

This goes to all the people saying a clarinet cannot play muti-phonics. If I could I would lecture you about the clarinet. It most DEFINITELY can play multi-phonics. I`ve heard many professional clarinetist do it. I`ve even done it! (just not that good ) So, instead of repeating what Rachel said I`ll just give her a pat on the back and a "Whoot!".

Some multiphonics are very easy but others are difficult. The easiest ones are produced by playing a note in the upper register and removing the register key causing a multiphonic between the original note and the one a twelfth below it.