Hearing aid compression maps a wide input range into a narrower output range

Evidence

Sensorineural hearing loss (SNHL) has a robust and profound effect on loudness, with a primary effect being abnormally rapid growth of loudness. Fowler (1928) was the first to report that listeners with SNHL experienced a similar range of loudness (from very soft to uncomfortably loud) but over a smaller range of decibel levels due to reduced audibility. He dubbed this phenomenon loudness recruitment. Numerous studies have followed Fowler’s initial observations, and an illustration of loudness growth in listeners with SNHL is illustrated in Figure 4–14, which shows a sample loudness growth function for a listener with 40 dB hearing loss plotted along with a loudness growth for a listener with normal hearing. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 838 (#expands, via linked claim)

Deficits in auditory perceptual abilities have a direct consequence for perception of sounds in natural environments. Audibility is the greatest factor in communication difficulties for listeners with hearing loss. However, supra-threshold deficits all contribute to poor auditory perception. … Specific deficits can be difficult to compensate for using modern hearing aid technology, and in many cases, hearing aid algorithms distort the cues available to a listener with SNHL. Despite the distortion provided by these algorithms, hearing aids provide benefits to speech understanding. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1777 (#expands, via linked claim)

Categorization

• XREF: connects to: The cochlea compresses a 100 dB input range into about 57 dB of response.; Wide dynamic range compression typifies all nonlinear hearing aid amplification; Noise gates and compression let aids make faint speech audible without amplifying noise (+9 more)

Broader Connections

• Hearing loss squeezes the full loudness range into a much smaller dynamic range #expands (0.90)
• Sensorineural hearing loss compresses the full loudness range into fewer decibels #expands (0.90) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 838
• Hearing aid algorithms distort auditory cues yet still improve speech understanding #expands (0.85) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1777
• Dynamic range compression trades vitality for noisy-environment audibility #qualifies (0.82)
• Cochlear compression operates via a gain control with finite attack and release times. #expands (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 3625
• Volume compression worsens speech intelligibility by flattening syllabic amplitude cues #qualifies (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2492
• Wide dynamic range compression degrades perception of speech temporal cues like stop consonants #qualifies (0.78)
• Hearing aids address audibility, recruitment, and noise but not resolution deficits #qualifies (0.75)
• Audio compression exploits masking to discard inaudible signal parts #corroborates (0.72) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2020