I read the Sport Pilot sound-proofing article with interest since I have a pretty noisy little 320 and have a couple of questions for the group.

1. I can imagine what materials would make good "absorbers", but don't have a good notion of what materials would make a good "barrier". I'd consider mounting it forward of the firewall unless the material is unsuitable for that location. Can anyone help?

2. I don't want to buy a pre-make sound-proofing kit unless very low cost makes it inviting. Anyone got sources for aviation grade absorbers and/or barriers in bulk?

If anyone has the expertise to flesh out the article with a more specific materials list, I'm all ears.

Bill