Hi,
Until recently when I upgraded to sierra (yeah, I'm way behind) my Macbook used to automatically put audio through my bluetooth speaker as soon as it switched on. But now, even though the speaker is connected, the audio doesn't come out of it until I select that speaker in system preferences. I find this quite annoying as the only reason I connect the speaker to the computer is so I can get audio from it. Is there a setting to tell the Mac to default to that bluetooth speaker?