  We investigate the speed of sound in $(d+1)$-dimensional field theory by
studying its dual $(d+2)$-dimensional gravity theory from gauge/gravity
correspondence. Instead of the well known conformal limit $c_s^2 \rightarrow
1/d$ at high temperature, we reveal two more universal quantities in various
limits: $c_s^2 \rightarrow (d-1)/16\pi$ at low temperature and $c_s^2
\rightarrow (d-1)/16\pi d$ at large chemical potential.
