"b.barwick" wrote in message
...
Try bluetak, make it pliable 'playing with it first' (the bluetack that
is)
then gently put over the dimple, a quick pull should restore the foil back
if your lucky!

Brian

its not foil, it is or was a rather rigid (relative term) plastic. Sucking
works on these types, usually.
If you are concerned, then replace with cheap Audax soft dome units, much
better sound, IMHO.
I had a few pairs of T27's, but replaced them with Celestion HF1300 / STC
4001 units, but I still like the Audax units, mounted in polystyrene
spheres.
cheers
Bryan