Bluetooth volume, other issues
So this is an issue that I experienced in previous cars, so it might not be a Bolt issue, but music over Bluetooth is very, very lower volume that anything else, both radio and the exact same music via CarPlay. I can consistently demonstrate this by:
1. Start listening via Bluetooth.
2. Plus in cable to start CarPlay.
The track continues playing at a much louder volume. Also,
3. Unplug the cable.
The Bolt does not "remember" that it was last playing anything via Bluetooth and switches to the last radio station used. This is not good.
I had done a bit of research and found some posts in various places over the years that suggested that Bluetooth volume could be improved by changing a couple of iPhone settings. But the Volume Limit setting was already off, as was the Sound Check setting. One thing that did make a (small) difference was turning off the equalizer on the iPhone (it had been set to Dance). I toggled some of these while listening on Bluetooth in my Bolt to see the effect of each. Even with the best combination of settings, though (and with the iPhone volume itself at near maximum), the difference between Bluetooth and not-Bluetooth is still quite large.