Have you put your ear close to the speakerphone while on a call? Is the speakerphone volume turned all the way up? You can hear some distortion when the person is talking.
I don't put my ear to the speaker because that would defeat the point of putting it on speakerphone. I also don't turn the volume all the way up because that would be crazy loud. At less than half volume the sound is plenty loud.
Then how your gonna know if your speaker is doing what mine is doing then? Just try it and get back. Like i mentioned before this is only happening when the volume is close to max or max on speakerphone it does not happen when the volume is low.