New answers tagged underlayment
I don't know what Green Glue is other than it appears to form a gasket of sorts. My thoughts would be to try insulation along with layering some dis-similar materials to avoid conductive transfer. I'd suggest a sandwich of XPS foam, topped with cork underlayment, then your finish floor (which, ideally, could be dry-core subfloor panels topped with ...
You have the answer in your question. I've used felt cushions in appartments to reduce traffic noise and it makes a huge difference. But beware, if you have a very uneven subfloor you'll get a lot of squeaky noises and no rosin paper or cushions are going to fix the problem.
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