Following comes a tutorial guide shows you how to convert flv to mp3 on Mac with FLV to MP3 Converter , operate as this:
step 1: Download FLV to MP3 Mac software, install and double click to open it.
step 2: Click "ADD File" button to start loading flv files that you want to convert to MP3 onMac. Input multiple flv files at the same is supported.

step 3: Under Profile folder, click comobox to select MP3 format. Then click browse Browse button to set output folder address.
tipsTips: if you need to reset your video settings, like video size, frame rate, bitrate, video or audio codec, Click Setting to set parameters directly.

step 4: After finishing the above settings, click convert Convert button to start convert flv to mp3 on Mac. The process bar will show you how the process goes on.