I was looking for an easy-to-use tool to convert audio files (e.g. FLAC or WAV to mp3). Finally stumbled upon SoundConverter.
As per soundconverter.org:
SoundConverter aims to be simple to use, and very fast. Thanks to its multithreaded design, it will use as many cores as possible to speed up the conversion. It can also extract the audio from videos.
It’s a great piece of software if you ask me. It’s minimal, very easy to use and conversion speed is quite fast.
Although it says “for GNOME Desktop”, it works fine on my KDE (Kubuntu) desktop.