The music has low quality when played from Spotify Connect compared to Firefox

[pnedkov]

I am having this issue from day one. Currently I am running Arch Linux with Spotify 1.0.72.117-1. When I listen to music from "This Computer - Spotify Connect" the quality is extremely low. The sound is muffled, the volume is low and the high frequencies are almost non existent. So in order to "fix" that I open Firefox (currently 59.0.1) and go to play.spotify.com. I login from the browser and then I go to Spotify App and select "Listen On Web Player (Firefox)". And boom: the sound quality is instantly a lot better. The difference is night and day.

I have a Premium subscription and "High quality streaming" is enabled in the settings. Why is this happening? Is there a way to get the best quality from the Spotify Desktop App without having to use Firefox?

Any ideas?