We all love the beauty of rosettes, but do they ruin the potential of the instrument? The evidence: At an Italian folk dance gig, I needed to quiet down an extremely loud bowl back mandolin so that it wouldn't completely stomp out the 19th century guitars. I placed a business card over part of the sound hole and suddenly had volume control!
A muffler on a car or a silencer on a firearm both work by causing the sound waves and air to change directions several times and/or directing it toward a sound absorbing material before releasing. A parchment "wedding cake" rosette seems ideal as a re-director or disruptor of air and sound waves (a muffler). The Stradivari style rose seems to be the same as using the business card to cover part of the sound hole on my mandolin. Evolution shows us that sound hole rosettes were done away with all together in the 18th century. Was it identified as problematic even then?
I'm not suggesting removing rosettes or building guitars without them. However, on the lute, I have found that a tightly knit Gerle or Leonardo's knot rosette will hinder the performance compared to the more open and loose designs. Surely there is someone who has or had enough different guitars in their quiver to shed some light on what style works best or the pros and cons of "flat laminate" vs "wedding cake.