Térhangzást

Térhangzást, often translated as spatial sound or sound localization, refers to the ability of a listener to perceive the direction and distance of a sound source within a three-dimensional space. This complex auditory process relies on several cues that the brain interprets to create a spatial representation of the sound environment.

Two primary binaural cues are crucial for horizontal sound localization. Interaural time differences (ITDs) are the slight variations in the time it takes for a sound to reach each ear. When a sound source is not directly in front or behind the listener, it will arrive at one ear milliseconds before the other. The brain uses this timing difference to determine if the sound is coming from the left or right. Interaural level differences (ILDs), also known as interaural intensity differences (IIDs), are differences in the loudness of a sound reaching each ear. The head acts as an acoustic shadow, reducing the intensity of a sound at the ear farther from the source. These level differences provide information about the sound's horizontal position.

Vertical sound localization, determining if a sound is coming from above, below, or at ear level, is more challenging and relies on monaural cues, meaning they are processed by a single ear. The shape of the outer ear, the pinna, plays a vital role. The complex folds and curves of the pinna filter sound waves in a direction-dependent manner, altering the frequency spectrum of the sound reaching the eardrum. The brain learns to associate these spectral changes with specific vertical locations. Reverberation and the relative intensity of direct versus reflected sound also contribute to distance perception.