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Abstract
Listeners with high-frequency dead regions (DRs) benefit from amplification of frequencies up to 1.7 times the edge frequency, fe, of the DR. Better consonant identification might be achieved by replacing the band from fe to 1.7fe with a higher spectral band. We aimed to identify the optimal band, using simulations with normal-hearing listeners. In experiment 1, nonsense syllables were lowpass filtered to simulate DRs with fe of 0.5, 0.75, and 1.0 kHz. Identification was measured for each of these base bands alone and with a bandpass-filtered band added (but not transposed). The added band either extended from fe to 1.7fe or its center frequency was increased, keeping bandwidth fixed in ERBN-number. Performance improved with increasing center frequency and then reached an asymptote or declined. Experiment 2 used a mid-frequency base band, and a lower-frequency added band. The results also showed a beneficial effect of frequency separation of the added and base bands. Experiment 3 resembled experiment 1, but with bandwidth fixed in Hertz. For higher-frequency added bands, the benefit was lower than for experiment 1.
| Abbreviations | ||
| ANOVA | = | Analysis of variance |
| DR | = | Dead region |
| ERBN | = | Equivalent rectangular bandwidth of the auditory filter for normal-hearing listeners |
| fe | = | Edge frequency of dead region |
| fe-sim | = | Simulated edge frequency of dead region |
| FFT | = | Fast Fourier Transform |
| HL | = | Hearing level |
| IHC | = | Inner hair cell |
| LSD test | = | Least-significant-difference test |
| SII | = | Speech intelligibility index |
| SPL | = | Sound pressure level |
| TEN(HL) test | = | Threshold-equalizing-noise test with calibrations in hearing level |
| VCV | = | Vowel-consonant-vowel |
| Abbreviations | ||
| ANOVA | = | Analysis of variance |
| DR | = | Dead region |
| ERBN | = | Equivalent rectangular bandwidth of the auditory filter for normal-hearing listeners |
| fe | = | Edge frequency of dead region |
| fe-sim | = | Simulated edge frequency of dead region |
| FFT | = | Fast Fourier Transform |
| HL | = | Hearing level |
| IHC | = | Inner hair cell |
| LSD test | = | Least-significant-difference test |
| SII | = | Speech intelligibility index |
| SPL | = | Sound pressure level |
| TEN(HL) test | = | Threshold-equalizing-noise test with calibrations in hearing level |
| VCV | = | Vowel-consonant-vowel |
Abstract
Las personas con regiones muertas (DRs) en las frecuencias altas se benefician con la amplificación de frecuencias hasta 1.7 veces la frecuencia borde, fe, de las DR. Se puede lograr una mejor identificación de consonantes reemplazando la banda de la fe a 1.7 fe con una banda espectral superior. Buscamos identificar la banda óptima usando simulaciones con normo-oyentes. En el experimento 1, silabas sin sentido se filtraron en un filtro pasa-bajo para estimular las DRs con fe de 0.5, 0.75 y 1.0 kHz. Se midió la identificación para cada una de estas bandas de base aisladas y con una banda adicional también filtrada (pero sin transposición). La banda agregada tanto extendida de fe a 1.7 fe o su frecuencia central fue aumentada, manteniendo el ancho de banda fijado en un número-ERBN. El rendimiento mejoró al aumentar la frecuencia central hasta llegar a una asíntota o declinar. En el experimento 2 se usó una banda base de frecuencias medias y una banda agregada de frecuencias graves. Los resultados también mostraron un efecto benéfico de separación de frecuencias de las bandas agregada y de base. El experimento 3 fue semejante al experimento 1, pero con un ancho de banda fijado en Hertz. Para las bandas agregadas de frecuencias altas, el beneficio fue menor que el del experimento 1.