I created a persistent live USB using:
- ubuntustudio 19.10
- mkusb
I follow these simple steps: https://www.howtogeek.com/howto/14912/create-a-persistent-bootable-ubuntu-usb-flash-drive/
I could setup all my soundcards successfully.
But the /etc/security/limits.d/audio.conf does not exist in the USB disk created nor the default user is in audio group so memory allocation does not work and generates error messages.
How to persist an audio.conf file and persist that the default user belongs to audio group in order to fully use the ubuntu studio from the bootable usb disk ? It would allow me to share my ubuntu-studio setup easily using copy/clone of my usb disk.
EDIT: In order to set Realtime permissions go to menu and start ubuntu-studio controls. Click on Realtime permissions and select CPU governor to performance and that's it.