Audio-encoder cosine sensitivity diverges from probe decodability
measured in 1 paperChen, Ding, Roman & Bello evaluate 13 frozen pretrained audio encoders across mono, stereo, binaural, and ambisonics on 7 linear-probing tasks [chen-etal-2026-probing-spatial-structure-audio] Source-related linear-probe improvements consistently exceed room-related ones for every model [chen-etal-2026-probing-spatial-structure-audio] A normalized cosine-similarity sensitivity metric (Delta = (cos-mu)/(1-mu)) under source vs room perturbations can diverge from linear-probe decodability of the same factor [chen-etal-2026-probing-spatial-structure-audio] Some models (GRAM-F, EINv2) show low sensitivity yet strong probing, while others (SFD, BANC) show high sensitivity but weaker probing, proving the two properties are distinct [chen-etal-2026-probing-spatial-structure-audio]