I don't think that there is any equalizer in Linphone.
The sound from the other participant depends on the chosen vocoder. If it's a wideband codec then it's better understandable.
For the ringing tone you can choose a sound file with a higher sampling rate.
-------- Original message --------
From: Egor Pavlov <address@hidden>
Date: 12/12/16 11:55 (GMT+00:00)
To: address@hidden
Subject: [Linphone-users] [Linphone-developers] parametric equalizer preset
We are using linphone, and we noticed that sound is not "deep" and "rich" as on Yealink/Polycom SIP phones. Do you have presets for parametric equalizer that that could make linphone sound more comfortable?