To create an audio file on a mac you have to connect a microphone to the computer then open the applications and open quicktime. Once quick time is open click the file at the top of the screen and then click new audio recording. Then click the red record button and begin to make the sounds or speak once this is done you have to click stop. Finally close the audio and choose a name for the file and where to save it then it can be opened as a .mov or .m4a
Another way of making audio files is by using an edirol to record sound whilst one the move this is possible because it is very sensitive to sounds because it has a microphone sensor one each side that is omnidirectional.