Download the Mac Audio Converter software and install the Audio Converter for Mac program on your Mac! An interface as the above will pop up!
Add audio files to the Mac Audio Converter's playlist, and prelisten the audio.

You can trim the length of the audiofiles by clicking the "Trim" button
When you get the effect you want just choose the "Profile", under which you can select the output foermat!
Press the
button to convert Audio on Mac!
The steps are simple, just try it, and you will find the Audio to Mac Converter is just the one you need!