Converting m4a to wav

[Apesbrain]

I converted m4a files which are aac on itunes to wav and to flac but did not notice any difference. Is it because the itunes music is aac and not alac?

I would not expect there to be any quality "difference". What you did added no new information to the files; it simply un-compressed them to a larger format.

If things haven't changed in the past few years, downloaded iTunes music files are 256 kbps AAC.