  Convolution models are powerful tools in many fields of spectral and image
analysis owing to their wide applicability, and X-ray astrophysical spectral
analysis is no exception. We found that relativistically broadened Fe
K${\alpha}$ line profiles obtained through many convolution models both within
and without Xspec show deviations from the profiles produced by their
non-convolution counterparts. These discrepancies depend on the energy grid
considered and on the shape of both the kernel and the underlying spectrum, but
can reach as high as 10% of the flux in certain energy bins. We believe that
this effect should be taken into consideration, considering how often these
models are used to study spectral features of lower relative intensity, and
advise great discretion in using them.
