I often dont have very good quality when I stream audio with Spotify.
It seems that spotify provides 3 kind of bitrates:
https://support.spotify.com/nl/learn-more/faq/#!/article/What-bitrate-does-Spotify-use-for-streaming
It woulf be nice if the bitrate could be selected in the spotify app or that the highest bitrate is used. Afterall, the app can only be used when you have spotify premium and then you can stream at the highest quality bitrate.