Sponge Padding In Car

[Lady J]

I have pulled down my car(2012 hatchback) for soundproofing and am noticing sponge in the rear,what are these for ?
I think it has something to do with sound absorbtion?am I right?if so should I put some where the front seatbelt is?as I am sure in other cars I have seen sponge in the seatbelt area.

[CTScott]

It is for some amount of sound isolation (I think maybe to break up the drum effect of that large cavity).

Toyota used to put it where the front seatbelt is and then later removed it on a recall, because it would burn when the seatbelt pretensioner blew during a crash.

[Lady J]

Ah that makes sense,I will just block it out,thanks Sir Scott as usual your the man!