Sourcing Original type soundproofing / carpet underlay

Hi folks Has anyone had any luck sourcing Original type soundproofing / carpet underlay bsically the bulkhead soundproofing has degraded beyond repair and I'm keen to replace with as similar spec as possible , I appreciate the genuine parts are no longer available.

Thanks

Alan

Most folks use Dynamat or like, then place the spongy rubber particle carpet pad over that.  It is cost effective, and sops water but also allows the cushy effect you are looking for.  You can buy it in different thickness's as well.