Sounds presented to both ears are perceived louder than to one ear

Evidence

When the same sound is presented to both ears, it is perceived to be louder than when it is presented to one ear only (Fletcher and Munson 1933 ). As a result, the loudness of diotically and monaurally presented stimuli, usually tones or noise, has been found to be equivalent when the monaural stimulus is between 3 and 10 dB more intense … These models can be used in hearing-aid fitting (e.g. Moore and Glasberg 2004 ), so hearing aids fitted using these models will have relatively reduced gain when fitted bilaterally in order to achieve a comfortable maximum loudness level. However, some recent studies have cast doubt on the ecological validity of the loudness summation literature. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1525

Categorization

• XREF: Connects to the reader’s broader loudness-summation knowledge base; also relevant to hearing-aid fitting design tradeoffs.