B&W dm7 speakers

I got these ones from my parents, and have a little problem :

The central circular part of the yellow speaker (mediums) is unsticking. It's made of a kinda rubbery piece of plastic, and i would like to stick it again as i trembles as fuck when i morningly listen to some ageispolis. One question came to my mind : wich kind of glue should I use if I want to be able to unstick it again for further fixings ?

my friend fixed his torn speaker membranes by applying rolling paper to it,lol. now they don't tremble.