Disentangling room acoustics though binaural measurements: The importance of individual ear-canal variations

Abstract

Evolution has endowed humans with extraordinary powers of hearing, powers that enable us to separate information-containing signals from noise and other signals with an acuity still unmatched by modern machines. We find that this ability depends critically on resonances in the ear canal. The ear canal and concha form a horn that boosts frequencies above 1000 Hz as much as 18 dB. These resonances are highly individual, headphones alter them, and just a 1 dB difference in the frequency balance at the eardrum can replace comprehension with confusion. We have developed a computer app that non-invasively equalizes headphones to accurately reproduce these resonances. Once headphones are individually equalized they reproduce binaural recordings with frontal localization and no head tracking. Using Lokki’s anechoic recordings we can manipulate a single binaural measurement to create a binaural rendition of a small ensemble nearly identical to a live recording in the same seat. We can then lower or boost specific ...