I recently bought a Bluetooth headset (Philips SHB4000), and got it to stop sounding like a phone after I told Linux (Mint) to use A2DP rather than HSP/HFP.
However, there's still an annoying crackling sound that I'd like to get rid of.
Some googling suggested that the "bitpool size" might be to blame, but I couldn't find any info on how to increase it on Linux. I know it's probably in some config file somewhere, but I haven't been able to find it.
~/.asoundrc
, which is described on the Alsa wiki.