Dave, this is a well timed post as I'm doing the same to my Amazon this winter. I'm using Dynomat Xtreme as have used in the past and it's very, very effective
http://www.ebay.co.uk/itm/Dynamat-Xt...wAAOxy79JSYbPx
I'll then cover with Dodo mat over this to act as soft underlay to the new carpet on the floor areas :. no moisture absorbing horse hair/hardura felt type materials.
http://www.ebay.co.uk/itm/6m-Roll-Ca...-/152364548635