Matched transaural synthesis with probe microphones for psychoacoustical experiments.

Area of Science:

• Acoustics
• Psychoacoustics
• Signal Processing

Background:

• Headphone presentation is standard for psychoacoustical experiments but has limitations.
• Ear canal calibration offers a potential improvement for auditory research.
• Transaural synthesis provides a loudspeaker-based alternative for immersive audio.

Purpose of the Study:

• To propose and evaluate transaural synthesis using loudspeaker signals calibrated to the ear canal.
• To compare transaural synthesis with crosstalk cancellation for psychoacoustical experiments.
• To assess the accuracy, reproducibility, and signal monitoring capabilities of the proposed method.

Main Methods:

• Computer modeling and manikin measurements were used to compare transaural synthesis (3-4 loudspeakers) and crosstalk cancellation (2 loudspeakers).
• Measurements utilized binaurally challenging signals and speech from a distant source in a reverberant room.
• Mathematical foundations for ear canal and eardrum signal relationships were reviewed.

Main Results:

• Transaural synthesis demonstrated superior performance in solving the inverse problem compared to crosstalk cancellation.
• Reduced average synthesis amplitudes, fewer outliers, and improved amplitude/phase accuracy were observed with transaural synthesis.
• Enhanced noise immunity was achieved, though head rotation immunity was dependent on loudspeaker placement.

Conclusions:

• Transaural synthesis with contemporaneous ear canal calibration is a viable and advantageous alternative to headphone presentation.
• The technique offers greater accuracy, reproducibility, and continuous signal monitoring for critical psychoacoustical research.
• This method enables direct comparison of listener responses to real and virtual auditory environments.