Vertical profiles of the vertical fluid and wave velocities. Horizontally and time-averaged fluid velocity v_z (blue curve), slow magnetosonic speed v_sz (light blue dashed curve), Alfvén speed v_Az (green dashed curve) and fast magnetosonic speed v_fz (red dashed curve), in units of c₀. The top panel shows results obtained in model Diffu4H (L_x = 4H, L_z = 10H) while the bottom panel is for the model Tall4H (L_x = 4H, L_z = 20H).