Persian Santoor

It keeps telling me to download apps every button I pushed

When the Santoor is active and a phone call occurs the app does not work and it has to restart. Also when the drum is being used on the app and I am playing my instrument the drum turns off

This is the only santur playing/tuning app I've found, and it's really well done. I wish the user could switch from 12 bridges to 9 bridges, because 9 is much more common for the instrument in the real world (it's distracting to have to ignore the extra bottom strings and top string). However, it is VERY exciting to switch among all the tunings and experiment with them on a virtual instrument, and that alone is clearly worth the app's price.