  Frequency distributions of local muon densities in high-energy extensive
air-showers (EAS) are presented as signature of the primary cosmic ray energy
spectrum in the knee region. Together with the gross shower variables like
shower core position, angle of incidence, and the shower sizes, the KASCADE
experiment is able to measure local muon densities for two different muon
energy thresholds. The spectra have been reconstructed for various core
distances, as well as for particular subsamples, classified on the basis of the
shower size ratio N_mu/N_e. The measured density spectra of the total sample
exhibit clear kinks reflecting the knee of the primary energy spectrum. While
relatively sharp changes of the slopes are observed in the spectrum of EAS with
small values of the shower size ratio, no such feature is detected at EAS of
large N_mu/N_e ratio in the energy range of 1--10 PeV. Comparing the spectra
for various thresholds and core distances with detailed Monte Carlo simulations
the validity of EAS simulations is discussed.
