I did a few more tests and found out why my Auracast transmitter don’t work.
The Bluetooth LE Audio specification (which applies to Auracast) allows for a number of different ‘Quality of Service’ (QoS) options. Using an IDC777 module from the Australian company IoT747, I tried which ones work and which ones don’t:
Here is the part of the Bluetooth specification that describes available QoS options:
- Options marked red don’t work - the Smart 3D app doesn’t even show the Auracast stream
- Options marked green work - yeah! They show up in the Smart3D app and connect right away.
- Unmarked options I was unable to test because the IDC777 module I was using for testing does not support them.
- The one line marked yellow is interesting: this one shows up in Smart3D, but times out. Just like the other two Auracast devices I have.
I think it’s a reasonable guess that my other two Auracast transmitter also use the ‘48_2_1’ mode. In fact, that’s probably the default for off-the-shelf Auracast transmitter right now, since it gives the best audio quality.
I also suspect (or hope) that this mode is supposed to be supported by ReSound HAs, but it times out due to a firmware bug. After all, options marked in red don’t even show up in Smart3D, whereas this one does.
So let’s wait for a firmware update and hope for the best.