Reliability of sidetone amplification effect in vocal intensity.

When the auditory feedback of a speaker's own voice is amplified the speaker reasonably tends to lower his voice. The reliability of this so called sidetone amplification effect was investigated in two experiments. In the first experiment feedback was modulated gradually during a session. In the second experiment the sidetone amplification effect was assessed over five successive days of testing. In both experiments the sidetone effect was very stable despite rather different eliciting conditions.