Mimocall audio quality

Hi Guys-

Did another test today in reverse - we used our studio setup as the caller, to see what kind of call quality Mimocall delivers when it’s receiving the best possible quality from a caller. Voice quality was generally good, but guitar signals over Mimocall sound occasionally squashed. Sounds either like noise reduction, similar to what Skype applies, or perhaps just an occasional very low audio bitrate. Is Mimocall doing any kind of speech-oriented noise reduction, and is there any way to disable it?