Instruments playback different volumes

Hi folks, playback/application volume issue here (Mac user):

  • visual feedback from levels in Halion shows as I’m hearing through my MacBook Pro speakers (see screenshots): Alto sax is loving life when I audition the notes on the Halion keyboard; all other instruments are feeble/non existent on the levels. The same is represented in playback. There are currently no dynamics in my piece.
  • when I use a different application (e.g. Safari for a Dorico support video), the volume is way louder
  • this wasn’t an issue before opening and using Logic Pro at the same time as Dorico

I’ve read some posts on expression maps and have watched this video. I’m nonethewiser.

Any support is greatly appreciated!
Many thanks,
Keiran