Sound speed profiles of the SSM computed using different solar chemical mixtures, Caffau et al. (2011, C11), Asplund et al. (2009, AGSS09-met), Grevesse & Sauval (1998, GS98), Asplund et al. (2021, AAG21), and this work (MB22-phot and MB22-met, see Sect. 3.3 for details). The shaded blue area represents the solar model uncertainties arising from the inputs to the model, see Villante et al. (2014) for details. Error bars in AGSS09-met and MB22-phot lines denote fractional sound speed uncertainties arising from helioseismic data (y-axis) and the widths of inversion kernels (x-axis).