sheet metal and sound deadener sounds like it would be really easy... and very easy to remove if i ever need to get inside the door at a later date. For sound quality, would it be better to make an MDF ring and fiberglass a door panel enclosure, or would it be better to make a complete enclosure out of MDF and paint it to look like fiberglass?... im just thinking about the acoustic properties of fiberglass as compared to MDF.