Cochlea a protein motor called prestin on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This "active amplifier" is essential in the ear's ability to amplify weak sounds. The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal through the middle ear (otoacoustic emissions). Otoacoustic emissions are due to a wave exiting the cochlea via the oval window, and propagating back through the middle ear to the eardrum, and out the ear canal, where it can be picked up by a microphone. Otoacoustic emissions
Jock Stirrup Jock Stirrup Marshal of the Royal Air Force Graham Eric Stirrup, Baron Stirrup, (born 4 December 1949), informally known as Jock Stirrup, is a former senior Royal Air Force commander who was the Chief of the Defence Staff from 2006 until his retirement in late 2010. He is now a Crossbench member of the House of Lords. In April 2013, he was appointed a Knight of the Order of the Garter by Queen Elizabeth II. As a junior RAF officer, Stirrup was a jet pilot, and saw action in the Dhofar War. Later in his career, he commanded No. 2