We are both saying the same thing, one of us just doesn't realize it.

 

Years ago I worked with an expensive telephone conference system. It was loudspeaking and was full duplex (talk and listen at the same time). At the beginning of a conference it would play pink noise on the speakers and make a model of the microphones, speakers, room reflections and phone line and use the model to make adjustments before a conference call. It tried to adapt to changes. Sometimes it would get confused if somebody opened a door or if a person moved in the room, then make an odd sound as it adapted to the change.
Its local and long distance (echo) feedback elimination was fairly good.

 

What is best and cheap op-amp IC do this job? Because the sound is a little fuzzy.

 

Cheap and best are opposites.

The LM358 dual opamp that you are using sounds fuzzy because it was designed a long time ago, produces hiss noise and produces crossover distortion. It uses a low power supply current that causes the hiss, crossover distortion and a poor high audio frequency response.
It is cheap at $.47US today at Digikey.

An LM833 is an audio dual opamp with none of the problems of the LM358 and it costs $.99US. Its power supply must be 10V or higher.

 

Thanks a lot