Harvey Fletcher invented the articulation
index (AI) in 1921. Fletcher was a brilliant, highly-regarded, and well-known acoustical scientist at AT&T's
Bell Labs whose work in communication sciences remains definitive today. He developed the AI metric to
assess the intelligibility of speech transmitted over the telephone system, but he also recognized applications
including audiology and hearing aid fitting. Fletcher's final, finely-tuned version of the AI calculation was published
in 1950 (with R.H. Galt). The Fletcher AI calculation has been dismissed as too difficult in favor of versions
that are simpler but less accurate in predicting speech intelligibility.
Inc now makes Fletcher and Galt's 1950 calculation available,
for the first time, in the form of an easy-to-use graphical interface with enhancements to accommodate hearing impairment
and binaural listening. Click here for product information.
Download AI history (.pdf)