[Garageband] 8 Bit format Wav file, cannot be used.

[jashsayani]

Hi,

I usually create iPhone ringtones with GarageBand and have created many...

How ever, with one of my files, it says, "The wav file has 8 bit format which vannot be used". What do I do ?
Any wav to convert the file from 8 bit to .... ?