Invention of the telephone
The carbon microphone was independently developed around 1878 by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention.
Real ear measurement
The first commercially produced real ear measurement available was made by Rastronics.
Help soon arrived. In the early 1980s, the first computerized probe-tube microphone
system, the Rastronics CCI-10 (developed in Denmark by Steen Rasmussen), entered the
U.S. market (Nielsen and Rasmussen, 1984). This system had a silicone tube attached to the
microphone (the transmission of sound through this tube was part of the calibration process),
which eliminated the need to place the microphone itself in the ear canal. By early 1985,
three or four different manufactures had introduced this new type of computerized probemicrophone
equipment, and this hearing aid verification procedure became part of the
standard protocol for many audiology clinics.