Something I noticed was that my outgoing audio was reported as low, and incoming audio was a little hot compared to the wire line I had before. So using OBiTalk "Expert Configuration", I changed
Configuration
Physical Interfaces
Phone 1->ChannelTxGain = -3
Phone 1->ChannelRxGain = 12
I did this also for Phone 2, since I have an OBi202. I had a friend with the same symptoms and cure.
I think 12 is the max, or else I would have gone a tad higher. The TX and RX are obviously from the point of view of the OBi which thinks it is transmitting to your ear and is receiving from the microphone. The numbers are decibels.