I think that the title is probably misleading. Here's what I have: One iTunes library with about 500GB of Apple Lossless music. One Logitech Squeezebox iPods, iPhones, etc. Here's what I want to do: I want to make a library of compressed tracks (AAC) to sync on my phones, iPods, etc. I want the Squeezebox to only stream the lossless files. I know how to make copies of the existing tracks and convert them to AAC but I don't know how best to manage it. Two libraries? Checking/Unchecking? How would you do it?