Klein-Hennig Martin, Dietz Mathias, Hohmann Volker
Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111, Oldenburg, Germany.
Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111, Oldenburg, Germany.
Hear Res. 2018 Mar;359:23-31. doi: 10.1016/j.heares.2017.12.007. Epub 2017 Dec 14.
Both harmonic and binaural signal properties are relevant for auditory processing. To investigate how these cues combine in the auditory system, detection thresholds for an 800-Hz tone masked by a diotic (i.e., identical between the ears) harmonic complex tone were measured in six normal-hearing subjects. The target tone was presented either diotically or with an interaural phase difference (IPD) of 180° and in either harmonic or "mistuned" relationship to the diotic masker. Three different maskers were used, a resolved and an unresolved complex tone (fundamental frequency: 160 and 40 Hz) with four components below and above the target frequency and a broadband unresolved complex tone with 12 additional components. The target IPD provided release from masking in most masker conditions, whereas mistuning led to a significant release from masking only in the diotic conditions with the resolved and the narrowband unresolved maskers. A significant effect of mistuning was neither found in the diotic condition with the wideband unresolved masker nor in any of the dichotic conditions. An auditory model with a single analysis frequency band and different binaural processing schemes was employed to predict the data of the unresolved masker conditions. Sensitivity to modulation cues was achieved by including an auditory-motivated modulation filter in the processing pathway. The predictions of the diotic data were in line with the experimental results and literature data in the narrowband condition, but not in the broadband condition, suggesting that across-frequency processing is involved in processing modulation information. The experimental and model results in the dichotic conditions show that the binaural processor cannot exploit modulation information in binaurally unmasked conditions.
谐波和双耳信号特性都与听觉处理相关。为了研究这些线索在听觉系统中如何结合，在六名听力正常的受试者中测量了由双耳（即两耳相同）谐波复合音掩蔽的800赫兹纯音的检测阈值。目标纯音以双耳方式呈现，或具有180°的耳间相位差（IPD），并且与双耳掩蔽声处于谐波或“失谐”关系。使用了三种不同的掩蔽声，一种可分辨的和一种不可分辨的复合音（基频：160和40赫兹），在目标频率上下有四个分量，以及一种具有12个附加分量的宽带不可分辨复合音。目标IPD在大多数掩蔽声条件下都能提供掩蔽释放，而失谐仅在可分辨和窄带不可分辨掩蔽声的双耳条件下导致显著的掩蔽释放。在宽带不可分辨掩蔽声的双耳条件下以及任何双耳分听条件下均未发现失谐的显著影响。采用具有单个分析频带和不同双耳处理方案的听觉模型来预测不可分辨掩蔽声条件下的数据。通过在处理路径中包含一个受听觉启发的调制滤波器来实现对调制线索的敏感性。双耳数据的预测在窄带条件下与实验结果和文献数据一致，但在宽带条件下不一致，这表明跨频率处理参与了调制信息的处理。双耳分听条件下的实验和模型结果表明，双耳处理器在双耳未掩蔽条件下无法利用调制信息。
