Scientific Article

Adapting the EC model to the frequency dependency of binaural masking level differences – Is this relevant for speech in noise?

Carl von Ossietzky Universität Oldenburg, Department für Medizinische Physik und Akustik and Cluster of Excellence “Hearing4all.connects”, 26129, Oldenburg, Germany

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 30 October 2025
Accepted: 8 April 2026

Abstract

Several binaural speech intelligibility models simulate human binaural processing using the Equalization-Cancellation (EC) mechanism, incorporating processing inaccuracies based on tone-in-noise detection at 500 Hz. Despite this, such inaccuracies are typically assumed to be frequency-independent in binaural speech intelligibility models. This study examines the validity of that assumption and explores how auditory filter bandwidth affects binaural masking release. Experiment I measured tone detection thresholds across frequencies from 250 to 2000 Hz in 12 normal-hearing and 5 hearing-impaired listeners, varying the interaural phase difference (IPD) of noise between 0 and 5π. Results were compared with EC model predictions. Binaural inaccuracies showed a low-pass effect, reducing binaural masking level differences (BMLDs) at higher frequencies. However, the EC model inaccurately predicted BMLDs at 250 Hz. Experiment II involved a subset of listeners performing speech-in-noise intelligibility tasks with low-pass filtered speech. This allowed assessment of whether tone-in-noise detection could predict speech recognition thresholds (SRTs), particularly in hearing-impaired individuals whose low-frequency hearing remained near normal. Findings revealed that adapting the model’s binaural inaccuracies improved SRT predictions beyond audiometric thresholds alone.