Sound deadening

[— kung fu jesus —]

I put some mat around the speakers and the scraps on larger portions of the door and I experienced the same as you. It helped a lot. I was surprised doing the same helped the noise coming from dash, too. Just small pieces placed on larger, flat surfaces helped remove some of the echo and buzzing/rattling from there. I put a larger piece on the under side of the instrument cluster hood and that yielded a nice result, too.