The third frequency component was then reduced in 3-Hz increments until the stimuli were perceived as “tuned” at which point the direction of stimulus the subsequent judgment of the stimulus as ‘mistuned’ at the direction was again reversals. The threshold was calculated as the average of the last four reversals. The stimuli were generated using Logic Pro 8 (Apple, Cupertino, CA) and were presented binaurally at a comfortable level (Sound pressure level = 55-60 dB) through headphones. The output of the acoustic system was calibrated using a sound level meter and artificial ear