AudioCoder is a Media Coder-based tool which will quickly convert audio files to the format of your choice. The program can import sound from all the main video and audio file types. And it can write most of them, too, with support for encoding MP3, Vorbis, AAC, WMA, AC-3, MusePack, Speex, FLAC, WavPack, APE, ALAC and PCM files.
You can customize the output file with a range of settings. Choose to create a few MP3s, say, and you’ll get the chance to select the file bitrate (anything from 56 to 320Kbps), encoding mode, sample rate and audio channels (mono, stereo, 4 or 5.1), as well as normalising volume, tweaking gain, and more. It provides a great deal of control over exactly how your chosen file conversions will be run.
Then you can convert multiple files in parallel, maximizing performance as every CPU core gets to work on its own individual tasks. If you don’t want to tie up your entire PC, then you can turn down the program’s speed control, reduce its priority perhaps, run it on just a single CPU core, and AudioCoder will run its conversion tasks without grinding everything else to a halt.