My home has a steel entry door that is 21yrs in use. Question:
does/can/will the insulation between the steel panels deteriorate over
time? I know my hearing isn't getting better as I age, so I'm wondering
if the insulation has failed. The sidewalk is 30' from the door and I
hear the 'goingson' clearly/loudly. The door is well-sealed against
air-drafts. If I put my ear to the inside panel, it's like a
speaker.....

Would a fibreglass door be a better choice for sound attenuation?
Thanks for any ideas/advice.

Dave S(Texas)