Hmm, listening the the samples [0], the OPUS one is almost unbearably noisy, whereas the MP3 while, while clearly low quality, is still listenable. Am I missing something, why is OPUS doing so poorly?
I will say the music part was interesting. I could mostly make out the song on the MP3. On Opus, I could barely tell there was music there. A lot of it was just missing.
Opus file is tuned for speech, mp3 isn't.
The opus file sounds unbearable when the music is playing, but is clearer otherwise.
Double the bitrate and opus is way ahead.