You don't *need* to convert to wav first. However, if you don't, then burning will take a lot more cpu power, and on top of that, what if you are doing something on your computer, and cdrwin isn't decoding the mp3 fast enough? Also, I'm sure that cdrwin's (or any other burning program that decodes on the fly) method of converting to wav won't give you the best possible sound. Your best bet is to stick with converting to wav first.