Speed of Sound in a Solid

The Speed of Sound in a Solid can be determined through the equation:$$v = \omega d = \sqrt{\frac{k_{s,i}}{m_a}d}$$

$v$ is the speed of sound in m/s.
$k_{s,i}$ is the stiffness of the interatomic bond.
$m_a$ is the mass of one atom.
$d$ is the length of the interatomic bond.