Sorry if this has already been covered elsewhere…
Just wanted to mention that the Equalizer feature in the Spotify music app has made a huge improvement in the quality of sound I hear using BT streaming with my Phonak Marvel HAs.
I turned the Equalizer on (Settings/Playback/Equalizer) and adjusted the sliders to INCREASE bass and DECREASE treble (counterintuitively in the opposite direction of my hearing loss). This removed the “tinnie” sound and picked up the bass nicely.
Play around with the sliders and different music to find a setting that works for you.