Compression Ratio
Also written as: CR — Compression Ratio
In hearing aid processing, the ratio of the change in input sound level to the corresponding change in output level, describing how aggressively the device reduces its gain as input increases.
Full Definition
Compression ratio (CR) is expressed as the number of decibels of input change required to produce one decibel of output change — for example, a 2:1 CR means a 20 dB rise in input produces only a 10 dB rise in output. It is a core parameter in wide dynamic range compression (WDRC) hearing aid fitting. Editors working on fitting software manuals, clinical guidelines, or product white papers must render it consistently as a ratio (e.g., '3:1') rather than a decimal or percentage. A CR of 1:1 represents linear amplification with no compression.
Usage
Usage note: Always express as a ratio with a colon (e.g., '2:1'), not as '2-to-1' in tables. Distinguish carefully from 'compression threshold' (the input level at which compression begins) when editing fitting documentation.
In Context
- "The audiologist reduced the compression ratio from 3:1 to 2:1 to improve the patient's perception of loud speech." — Hearing Aid Fitting Notes
- "Table 2 lists the compression ratio settings across each frequency channel." — Clinical Research Article