Magnitude of the acoustic reflex for either homophasic (0°) or antiphasic (180°) binaural activating signals presented in a background of noise

The threshold of the acoustic reflex (TAR) and the magnitude of middle-ear muscle response were measured for a homophasic (0°) and an antiphasic (180°) 550-Hz tone in a background of in-phase noise. Signal-to-noise ratio ranged from—20 dB to +15 dB. Whereas previously reported data shows an effect of phase on the percept of loudness, no evidence of a phase effect was measured for acoustic-reflex responses. These results are interpreted as evidence against a relation between loudness and acoustic reflex for binaurally presented signals.