Traditional large-eddy simulation (LES) provides good results on standard benchmark turbulent flows, but engineering applications involving more complex geometries are restricted. This is mainly due to the physical hypotheses of homogeneity, isotropy, or local equilibrium of the subgrid-scale (SGS) models, which are questionable in more realistic configurations. It appears essential to qualify the built-in filters of LES models before performing coarse mesh/high Reynolds number computations. A study of the Smagorinsky and the Schumann models with a mesh-independent filtering length larger than the mesh size is presented in this paper. The forms of the associated built-in filters are identified, and a control of the filter length through the SGS model is performed. Finally an asymptotic behavior of the filter is found to be independent of the spatial scheme for large filter length. This work is partly an assessment of previous theoretical studies on LES filters and kinetic energy spectra. (C) 2001 American Institute of Physics.