Binaural recordings of broadband noise-bursts played from a loudspeaker in my dining room. Analyses show that cues in some frequency bands resemble ‘ideal’ values  before recent reflections arrive. Values then drift and fluctuate due to frequency-specific amplitude modulations, acoustic reflections and background sounds.

• • ITDs fluctuate broadly prior to when each noise burst starts (before 0 ms).
• • Values then contract for ~20 ms as amplitude rises, as would occur in a quiet, anechoic, setting.
• • Values next begin to drift and fluctuate after ~20 ms, due to amplitude modulations inherent to the 400 Hz auditory band, interactions of surrounding frequencies, acoustic reflections and background sounds.

Recordings for 0° azimuth, cropped 1 second before and after the recorded tone’s onset.

400 Hz auditory filter

Noise bursts (200 ms) with 10 ms on/off ramps (Hanning) were played from a single loudspeaker in my dining room well above average ambient noise levels (~36 dB). Ten recordings were obtained at random times over 2-3 days using the Neumann KU100 dummy head rotated in 10° azimuthal increments during each recording session.

The Neumann KU100 dummy head and speaker were positioned 2.8 m apart and 1.35 m above a hardwood covered concrete floor in my 5.25 X 4.2 X 2.5 m dining room. A table 2 X 1 X 0.75 m was positioned between the microphone and speaker, all slightly offset in the room so that the left microphone was 1.7 m from a large shuttered window along the lefthand wall and 2.4 m from a solid righthand wall. A passageway behind the speaker allowed sound to travel through 2 rooms and a foyer to another passageway behind the microphone. All of these factors contribute to a binaural room impulse response (BRIR) that is complex and somewhat long.

Binaural room impulse responses (BRIR) for single loudspeaker recorded with the Neumann KU100 dummy head at 0° azimuth. 

Tap or move cursor over element to pause slideshow