having the rook top 18 these include turf underlayment playground underlayment and other systems where the underlayment lies between a wear surface and a drainage system one aspect of the system disclosed is that interaction between plastic and a flat surface may be noisy for example the system may flutter when displaced relative to the surface above or below and generate sound at a decibel level that may be objectionable therefore alternate embodiments include a thin foam or felt layer interposed between the upper surface 12 and the disclosed energy absorbing system for instance most turf systems are installed over a compacted stone base in such applications a permeable non woven or woven pp geo textile not only deadens the noise but also prevents the disclosed system from settling substantially into the stone base or the stone base from migrating up between the frustoconical structures 15 this thin layer promotes drainage but also prevents relative movement or migration of adjacent layers in an indoor environment placement of a foam or felt pad underneath the energy absorbing system would tend to deaden that noise it will be appreciated that the underlayment systems may or may not be recoverable for example a non recoverable polypropylene or thermoplastic urethane or other thermoplastic may be suitable for use in basements when moisture and mildew could otherwise be an issue in such applications the energy absorber 10 would not crush significantly let alone recover to or toward an undeflected state instead of cushioning the blow by deformation resistance to impact would be relatively inelastic then in the absence of drainage holes the disclosed system would constitute a reservoir or vapor barrier as used herein the term u201c thermoplastic u201d means u201c a polymer material that becomes pliable.