A multilayer foam composite element whose total thickness d comprises at
least three layers composed of an open-cell foam, where at least one of
the internal layers has recesses and the two outermost layers have no
recesses, wherein i) the volume of the recesses in the internal layer
having recesses is from 20 to 70% by volume, and ii) the thickness of the
layer having recesses is from 20 to 80% of the total thickness