Does anyone know how to find the codec Phonak uses for Bluetooth connections?
I have a friend who is a retired EE professor and he is putting together a device for me that is something like the Roger Select, using electronics he has in his shop and a bluetooth transceiver he has purchased.
It works, but the latency problem is significant. He says if he knows the correct codec, he might be able to improve it.
The codec it uses is a relatively high latency one (which is what makes Bluetooth less attractive than the TV Connector for many applications) - I think it is likely using SBC when in A2DP.
In some documentation, Phonak refers to their approach as “Bluetooth Classic”:
Phonak’s proprietary AirStream wireless protocol is lower latency but if course it’s not Bluetooth. This is how the HAs communicate with accessories like the PartnerMic and TV Connector for audio streaming where latency is most critical.
Do you have any details about what modules your friend is using? Is it an nRF? Would your friend be interested in open-sourcing any aspects of the design and/or code? I for one would be very interested in experimenting…
From the User Guide:
Bluetooth:
4.2 Dual-Mode
Profiles Supported:
HFP (Hands-free profile), A2DP
Emission standards:
EN 60601–1-2:2015
IEC 60601–1-2:2014
EN 55011:2009+A1
CISPR11:2009/AMD1:2010
CISPR22:1997
CISPR32:2012
ISO 7637-2:2011
CISPR25:2016
EN 55025:2017
I got this response from Phonak Support today:
Thank you for contacting Phonak with your inquiry. Phonak hearing aids use A2DP and HFP. They do not use aptX.
Thanks for the links. I do, of course, have the user manual in pdf form. I had seen the first linked article about a year ago, but I’d forgotten about it. I’ll forward it to my friend and ask about sharing his work.