Hello,
I have compared the audio volume in Linphone for Android with other VoIP services such as Skype and WhatsApp. In all cases, either with the loudspeaker on or off, the audio volume with Linphone is significantly lower than that in other apps. This may be due to some amplitude setting in the Linphone source. Please let me know which part in the source can be modified to increase the audio volume in Linphone.