You can try changing the Bluetooth AVRCP Version to 1.6 (it might be set to 1.4 or 1.5 depending on your phone - mine defaults to 1.5). You have to change this setting in Developer Options which have to be enabled to be visible...
To enable Developer Options: open settings -> system -> about phone -> tap build number 7 times
Developer Options should then appear on the main settings menu somewhere (type 'Developer' in the settings search box if you can't locate it).
The Bluetooth settings are usually about halfway down the Developer Options screen - I wouldn't play about with anything else in there unless you know what you are doing!
Thanks for the idea Berwhale.
Sadly, switching from the default 1.4 to 1.6 made no difference at all to the level. Note that I am using the ability of the Telegram client to leave a voice message for yourself to test the level. As an additional control, I also did the same while recording in my Android voice recorder app.
However, I have a set of cheap bluetooth in-ears for the gym etc and tried the same tests with them. The surprising result was that they too recorded at a low level in Telegram and voice recorder.
So while I was doing all this my son messaged me on the facebook messenger app. So I left him an audio message in return. Once I had finished the audio message, I played it back and lo and behold, the level the message had been recorded at was much higher than for Telegram and Voice Recorder.
I was on the verge of returning the AKG to Amazon but now I'm thinking the behaviour may be app specific, so I will experiment a bit more.
Cheers!
