Hi Curt the midrange risers you see are atually foam sheets i found at an artsandcraft store. I measured and cut with a yardsyick and knife.It's actually the same stuff Wilson uses on their Sophias and Watt Puppies. idid this at the same time as the FST ugades about six months ago. They work in anitidifraction, but the tweeters are brians foam which Idiscovered wors best for the extreme highs. Glad you noticed them. Much appreciated.Thanks,Stan
