This demonstration estimates the sound pressure at which a tone becomes audible in binaural noise under four presentation conditions. The noise can
  1. be identical from ear to ear (homophasic),
  2. have a 180 degree phase shift from ear to ear (antiphasic),
  3. be uncorrelated from ear to ear.
Four intervals are presented
  1. the noise is presented alone,
  2. the noise with homophasic tones - identically to the two ears,
  3. the noise with monaural tones - to the left ear alone,
  4. the noise with antiphasic tones - with 180 degree phase shift from one ear to the other.
The level and bandwith of the noise and the frequency of the tone can be specified. The level of the tone can be increased or decreased from presentation to presentation.

When listening with only your left ear, the thresholds of all three tonal presentations should be the same. With only your right ear, no tone should be heard during the first and third presentations. The tones may be audible during the second and fourth burst, depending on the tone level.

When listening with both ears, the relative thresholds for the three tone presentation conditions will vary depending on type of noise presentation, noise bandwidth and level, and tone frequency.

Instructions
Choose the method of presenting noise, then click Begin.


Parameters
Noise      Level - dB SPL
Highpass Frequency - Hz      Order
Lowpass Frequency - Hz      Order
Tone Frequency - Hz
Initial Tone Level - dB SPL      Increment - dB
Hz - Sample Rate      dB SPL - Calibration