In Reply to: 3" open cell foam insulation posted by frog on February 23, 2003 at 10:28:25:
Sorry, I can't comment on the product you have in comparison with R11 and R13. I use some closed cell foam products as a fill and they work quite well, acting as a solid mass and a damper. But I don't know if the product you are talking about will work as a suitable replacement for R11 or R13 in this application. I suppose it couldn't hurt to try. For a test - Listen to the port closely with your ear. The midrange should sound distinctly muffled, and as absent as possible. If that isn't the case, then the foam product isn't sufficient and you should replace it. But if the midrange is sufficiently attenuated, you're good to go.
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