Can I have a different volume for Vio and for background music apps?
The volume of the VIO app is too low compared to that of the music apps on the phone. If I use Vio only, it's not an issue, I just increase the volume. But if I also listen to music in the background (Spotify, Tidal, or just an app that plays local mp3s), then the volume of the Vio is too low compared to that of the music. If I increase the volume so as to hear the Vio, the music becomes deafening. If I decrease the volume, I can hear music fine but struggle to hear the Vio.
Is there anything that can be done?
The Vio app doesn't seem to have its own separate volume control.
Can I pair the Vio directly to the Cardo Bluetooth?
There is an Android app https://play.google.com/store/apps/details?id=com.spycorp.appvolumecontrol that changes volume when certain apps are open or closed, but it's only for when apps are open or closed - it says that Android doesn't let you have a different volume for a foreground app and for a background app.