If you're using a high-end bluetooth headset on your Macbook Pro it's likely your mac is using an audio codec which favors battery efficiency over high quality. This results in a drastic degradation of sound, the SBC codec is the likely culprit, read more about it here.
- Play a song on your headphones
- Option (⌥) click the Bluetooth button at the top of your screen
- If you're using AAC or aptX, you can stop here—those are the highest quality codecs.