Radial variation of the azimuthally averaged travel-time shifts measured for the simulations with z_WD = 450 km and B_u = 1500 G (black), B_u = 2500 G (blue), or B_u = 3500 G (red). The green dashed line corresponds to the results for a sunspot with the thermal structure of the model with B_u = 2500 G and z_WD = 450 km but with the magnetic field set to zero (see Felipe et al. 2016). The columns correspond to different phase-speed filters, from lower phase speed (left panels) to higher phase speed (right panels). The rows correspond to frequency filters with increasing frequency from top to bottom. The errors bars shown represent an assessment of measurement errors of the travel-time shift differences between two models (see text).