I've just bought myself my first reasonable high-end phone, a Moto Z Play. I've downloaded the Facebook app and set notifications to vibrate only, no sound. However i'm still having a sound effect every time I receive a notification, i've changed the sound effect within the app and it isn't the sound effect i'm hearing whenever I receive a notification. Is there some other setting in the phone that's causing the notification sound effect even though it's disabled in the Facebook app? I don't want to disable notifications completely, just the sound effect.