Andy's Hearing Sandbox
 Is tinnitus just fibrilation of hairs? We "hear" a sound  an annoying hiss, at high frequency, say; is that hairs activating nerves, or is that nerves imagining hair activation?
If it's hairs fibrilating, could we construct a defibrilator? Could we give those hairs a shock back to normalcy?

Question:(From this site:)
Loudness of a sound is proportional to the square of the amplitude of the vibration producing the sound. Explain.
Solution:The loudness of sound depends on the amplitude of vibration of the vibrating object. Greater the amplitude of vibration, louder the sound will be.When a Sitar string is plucked lightly, then it vibrates with a small amplitude and produces a faint sound or feeble sound. When a sitar string is plucked hard, then it vibrates with a large amplitude and produces a very loud sound.
The loudness of sound is directly proportional to the square of the amplitude of vibration.
If the amplitude of vibration is doubled, then the loudness will become 4 times.
If the amplitude of vibration is halved, then the loudness will become onefourth.
The loudness of sound is expressed in the units called the Decibel. The symbol of the decibel is Db.
At a loudness of above 80 Db, the sound become physically painful. And at about 140 Db level, the sound hurts too much.
 Mathematica

Decibel  a tenth of a Bel, of course!:)
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or rootpower quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10^{1/10} (approximately 1.26) or rootpower ratio of 10^{1⁄20} (approximately 1.12).
....
Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10.[5] That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing rootpower quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and rootpower levels change by the same value in linear systems, where power is proportional to the square of amplitude.  Joe's suggestions:
 HeadsUp Display
 Arduino with MIDI support built in
 Electret microphones
 Joe suggests Adafruit for purchases, and Reprap....
 Wave shield voice changer
 "I would suggest a bone transducer in place of an ear piece."
 From Jameco electronics: Velleman's voice changer solder assembly kit: change pitch, add vibrato effect; Jameco part # 2130731
 I did a search for Mathematica and hearing tests, and found a few interesting articles:
 AudioSense: Enabling Realtime Evaluation of Hearing Aid Technology InSitu
 Why can I still hear sound when the frequency of the periodic function inside Play is lower than the range of human ear? (Answer, with video)
 Went looking for Mathematica synthesizers, and
 found one! This one got me started on my own Mathematicabased hearing tester.
 this one looks interesting.... I dumped the code into Mathematica.
 Encylopedia Britanica has a good article on sound
 I’d said I’d look into analysis for python and R: here are some early looks
 Python:
 python libraries for sound analysis, including
 pyAudioAnalysis; its github page includes a
 wiki, including some reference articles, like this
 article Intro to Audio Analysis (with pyAudioAnalysis examples)
 Loris, which may already do some of the tricks we envision (which is C++, but has a python module)
 pyAudioAnalysis; its github page includes a
 Interesting comments here on picking off frequencies, RE the FFT
 realtime processing in Python
 python libraries for sound analysis, including
 R code: e.g.
 EMUSDMS: An R library for signal processing
 spectral analysis, including dft
 Real time analysis in R
 EMUSDMS: An R library for signal processing
 Python:
 Soundmagic Spectral:
 "SoundMagic Spectral is a freeware suite of 23 Audio Unit plugins that implement realtime spectral processing of sound. This set of effects give you unprecedented control and creativity in the processing of audio, whether from static audio files or live audio streams."
 Only for the Mac at this time...:(