I had a report of some rattling in a hoop and I am looking into this now. At the moment assembling each hoop is something of an art ( I do it all myself and takes several hours, but am still learning how to perfect the process) If I wrap the insides too much then there are problems and if too little there may be play inside. I use three or more kinds of tape inside, and one is a light diffusion tape that sounds a bit crinkly – I will post more when I have this sorted.