I have always used headset/earbuds for music (soundcore 14p,space one). So I was suprised to hear the audio quality from my recently purchased car which has bose speakers. With a little digging I found that the 6.1.1 update removed options to change eq for lower frequency (grayed out) if the phone is used without external speaker (img 1). However, if l'm connected to Bluetooth speakers I can do it
(img 2). This issue is android auto is treated as if the phone isn't connected to an external sound source and therefore sound very tinny, however if I connected it as a Bluetooth device I can adjust it.
Which means I have to choose between AA or good sound quality.
