Render audio only in render?

I found an old thread on this and apparently there used to be a “mixdown” button under audio in the scene tab. Nowadays you find a “mixdown” button under render and audio. When I’m doing this it creates for me a small flac file that I can not open and play in any program (including blender). Anyone know how to make a mp3 file in blender??

In the render panel press the Audio button to render just audio

In the file browser that then appears select the audio format