How do I adjust the volume for persistent level 1 notifications

Hey everyone,

I have a rule setup in Hub to treat any emails with the high priority flag as a level 1 persistent message. I cannot find a way to adjust the volume for this alert, at times I need it to be as loud as possible, at times I need it to be close to silent.

I have tried adjusting all 3 of the volume sliders under the sound settings (ring, alarm, media), but none of them have any effect whatsoever on the volume of the level 1 hub alert.

What and where am I missing this setting?

Thanks!

(KEYone, if that matters)