We use ultra-cold one-dimensional Bose gases to simulate a mass quench of the Klein-Gordon model and investigate the information propagation. We measure local velocity fields after the quench and observe the propagation of correlations along sharp light-cone fronts. For inhomogeneous background densities, these propagation fronts are curved. For sharp edges, the propagation fronts are reflected at the system’s boundaries. By extracting the space-dependent variation of the front velocity from the data, we find agreement with theoretical predictions based on curved geodesics of an inhomogeneous metric. This work extends the range of quantum simulations of non-equilibrium field dynamics in general space-time metrics [1]. [1] arXiv:2209.09132