Hello friends. Its very simple. Don't stress alot about it. Just take a safety pin and gently clear the ear piece holes. I did the same now and was surprised that the voice is clear now.
Try this on the first priority then go with software etc.
Your speaker is probably dirty. This was my problem. Use tape. Rub it over the speaker really well then pull off. Do this a few times. The stronger the tape the better it should work. I used duct tape. My friend used scotch tape. But they both worked.