peter Ususally there is a symbol displayed in the iOS status bar on top when you are connected to a bluetooth audio receiver. Didn't you see that?
When ST3 is open there is NO symbol that appears when you are connected to a bluetooth audio device like my LOGITEC BLUETOOTH ADAPTER.
As i have two of these great little devices i use one at home and one at a gig so i can easily use my ST3 on the iPhone to play backing music at breaks, this is fantastic, and when i get home i can also hook in to my studio setup without any hassles i also use my iPad pro that i perform with to hook up to these devices as its very practical to quickly get audio in to where i want when not performing but i use a cable from headset out to feed the PA when performing as i don't yet trust wireless.
The big problem is if my iPhone has not hooked up to this device first and i turn my iPad on, it hooks up automatically which then disables my audio out from the headphone jack , it has just done it again this morning, as i left the power on in my studio and the Logitech bluetooth audio interface was powered as usual, the iPad automatically hooked up to it again and disabled my speakers, this also works the other way if i happen to plug the device in my studio wanting to then hook up to my iPhone the ipad hogs the connection first as its fired up in my kitchen so again no audio out of my ipad.
THIS IS VERY DANGEROUS PRACTICE , WHY?
When performing i don't want my audio out of my ST3 to disappear because the bluetooth system has decided it has found another audio out source, if for some reason it has found a bluetooth device at any time and anywhere i expect a confirmation first otherwise i am red faced in the middle of the stage.
As i said before , two things that bother me , i want to see where my audio is going where the huge master fader is as its the last control point and an output device indicator would be perfect right there, perhaps dedicate the end of the fader to indicate the name of device it is going to.
I know NOW that its one more page away in AUDIO SETTINGS but it took me lots of research to discover this problem so I'm ok jack , but its avoidable by presenting us with the information where the master output fader is as most people will go through what i did, plus i would make sure ST3 does not assume just because i fired up a bluetooth device near me it is meant to be used by it and hook up automatically and disabling the headphone jack without warning and leaving you audio-less while possibly performing as worse case scenario.
Perhaps have the logic this way, whatever the last output device was used when you fire up the system if the same output device exists it automatically hooks up to it again BUT if the last used audio output device is not present then ask a question do you want to change your output device and give us choice if multiple devices are present.
But don't just ASSUME and knock out my precious audio that might be entertaining an audience, this is dangerous i am glad i found this as i will not be powering up any bluetooth adapters while on stage at the moment, it dont make me feel warm and fuzzy 🫨
After more playing around i think this problem is an APPLE operating system issue as it also does the same thing with youtube , sorry Peter for making it look like an ST3 thing but i still would like to see the connection to a device in a more obvious place in ST3.
After even more investigating, its beginning to look like the problem is a bit of both, i am just talking to Apple specialist and will report the outcome.