  The present study deals with the extraction of the symmetry energy from
heavy-ion collisions at intermediate energies. Using the isospin quantum
molecular dynamical (IQMD) model, the dependence of the sum of the charge
number for fragments with $Z\ge2$ ($Z_\textrm{bound}$) on the multiplicity of
neutrons ($M_n$) from the projectile spectator fragmentation of $^{124}$Sn and
$^{124}$La at 600 MeV/nucleon is compared with the experimental results of the
ALADIN-2000 Collaboration. The comparison suggest a soft symmetry energy. In
addition, the sensitivities of the symmetry energy towards the
$Z_\textrm{bound}$ dependence on proton multiplicity ($M_p$), neutron-to-proton
single [$R(n/p)$] and double ratio [$R_D(n/p)$] are also examined. The
$Z_\textrm{bound}$ dependence of $R(n/p)$ is found to be the most sensitive
observable towards the symmetry energy. The ALADIN Collaboration should extend
the results for $R(n/p)$ in the near future.
