Effects of Slow- and Fast-Acting Compression on Hearing-Impaired Listeners’ Consonant–Vowel Identification in Interrupted Noise

• Main Authors: Borys Kowalewski, Johannes Zaar, Michal Fereczkowski, Ewen N. MacDonald, Olaf Strelcyk, Tobias May, Torsten Dau
• Format: Article
• Language: English
• Published: SAGE Publishing 2018-10-01
• Series: Trends in Hearing
• Online Access: https://doi.org/10.1177/2331216518800870
• ISSN: 2331-2165

There is conflicting evidence about the relative benefit of slow- and fast-acting compression for speech intelligibility. It has been hypothesized that fast-acting compression improves audibility at low signal-to-noise ratios (SNRs) but may distort the speech envelope at higher SNRs. The present study investigated the effects of compression with a nearly instantaneous attack time but either fast (10 ms) or slow (500 ms) release times on consonant identification in hearing-impaired listeners. Consonant–vowel speech tokens were presented at a range of presentation levels in two conditions: in the presence of interrupted noise and in quiet (with the compressor “shadow-controlled” by the corresponding mixture of speech and noise). These conditions were chosen to disentangle the effects of consonant audibility and noise-induced forward masking on speech intelligibility. A small but systematic intelligibility benefit of fast-acting compression was found in both the quiet and the noisy conditions for the lower speech levels. No detrimental effects of fast-acting compression were observed when the speech level exceeded the level of the noise. These findings suggest that fast-acting compression provides an audibility benefit in fluctuating interferers when compared with slow-acting compression while not substantially affecting the perception of consonants at higher SNRs.