  The total energy of a fireball is commonly obtained from optical measurements
with an assumed value for luminous efficiency. Acoustic energy measurements
offer an independent means of energy estimation. Here we combine optical and
acoustic methods to validate the luminous efficiency model of Borovi\v{c}ka et
al. (2020). Our goal is to compare these models with acoustic measurements of
meteoroid energy deposition. Employing theoretical blast scaling laws following
the approach of McFadden et al. (2021), we determine explosive yields for both
fireball fragmentation events and cylindrical shocks for four different bright
fireballs. We model fireballs using the MetSim software (Vida et al., 2023) and
find that the Borovi\v{c}ka et al. (2020) model produces agreement better than
a factor of two for our three chondritic fireball case studies. The major
exception is an iron meteorite-producing fireball where the luminous efficiency
is an order of magnitude higher than model predictions calibrated with stony
fireballs. We suggest that large disparities between optical and acoustic
energies could be a signature of iron fireballs and hence useful as a
discriminant of that population.
