  We present new, high-to-intermediate spectral resolution stellar population
models, based on four popular libraries of empirical stellar spectra, namely
Pickles, ELODIE, STELIB and MILES. These new models are the same as our
previous models, but with higher resolution and based on empirical stellar
spectra, while keeping other ingredients the same including the stellar
energetics, the atmospheric parameters and the treatment of the
Thermally-Pulsating Asymptotic Giant Branch and the Horizontal Branch
morphology. We further compute very high resolution (R=20,000) models based on
the theoretical stellar library MARCS which extends to the near-infrared. We
therefore provide merged high resolution stellar population models, extending
from ~1000 AA to 25,000 AA. We compare how these libraries perform in stellar
population models and highlight spectral regions where discrepancies are found.
We confirm our previous findings that the flux around the V-band is lower (in a
normalised sense) in models based on empirical libraries than in those based on
the BaSeL-Kurucz library, which results in a bluer B-V colour. Most noticeably
the theoretical library MARCS gives results fully consistent with the empirical
libraries. This same effect is also found in other models using MILES, namely
Vazdekis et al. and Conroy & Gunn, even though the latter authors reach the
opposite conclusion. The bluer predicted B-V colour (by 0.05 magnitudes in our
models) is in better agreement with both the colours of Luminous Red Galaxies
and globular cluster data. We test the models on their ability to reproduce,
through full spectral fitting, the ages and metallicities of galactic globular
clusters as derived from CMD fitting and find overall good agreement.
{Abridged}
