Inversions of the Γ₁ profile as a function of normalised radius in the solar enveloped, determined using the Larson & Schou (2015) dataset. Left panel: subdomain of the method for the Z determination (indicated by the orange vertical lines). Right panel: subdomain of the method for the X determination. The green curve and symbols are associated with model M1 (FreeEOS), whereas the purple curve and symbols are associated with model A2 (SAHA-S v7). The red and blue lines illustrate models A1 and A2 and M1 and M2, respectively.