  We describe and characterize a setup for subrecoil stimulated Raman
spectroscopy of cold cesium atoms. We study in particular the performances of a
method designed to active control and stabilization of the magnetic fields
across a cold-atom cloud inside a small vacuum cell. The performance of the
setup is monitored by {\em copropagative-beam} stimulated Raman spectroscopy of
a cold cesium sample. The root mean-square value of the residual magnetic field
is 300 $\mu G$, with a compensation bandwidth of 500 Hz. The shape of the
observed spectra is theoretically interpreted and compares very well to
numerically generated spectra.
