iTunes prefs -> General.
Click the *Import settings* button and set it to AAC.
Select all teh songs then menu Advanced -> Create AAC version.
Then delete the MP3 versions.
Note that converting MP3 to AAC will result in degraded audio quality and larger file size if you use a higher bitrate than the MP3, with no benefit other than they are in AAC format. Anything that will play AAC will play an MP3.
This why I asked, "why" do you want to convert them?
What is the bitrate of the current MP3 files?
What bitrate do you want to convert them to and why?
I just did a test and the starting MP3 album was 153.1 MB and after making thenm into ACC they were 152.2 MB and the sound quality* did not change at all, so you should check your speaker setup mate.
It has nothing to do with my speaker setup.
You should study up on lossy codecs such as AAC (
not ACC) and MP3.
Converting any file to a lossy format (AAC) will result in degraded quality. The amount of degradation depends on many factors but it
will happen.
Converting from MP3 to AAC is pretty much useless unless you absolutely need an AAC file, which is what I was trying to ascertain with the original poster and why th eneed to convert to AAC.