Angular distance between inward and outward waves against Δν for a 1.1 M_⊙ evolution sequence. Frequencies between the acoustic cut-off frequency at the surface and about 50% greater than ω_a are considered. For every model in the sequence, frequency-averaged values of the angular distance and 1σ dispersions are calculated separately for ℓ = 1 (red points) and ℓ = 2 (green points) waves. An angle of 180° means no inner reflection.