1. Medical Dissection Lab
RoshanS(ED11B052)
SaneethS(ED11B053)
Chaitanya Kumar D(ED11B045)
Audiometer
Abstract: To Study various modules and the functioning of the
Audiometer.
Introduction:An instrument used to measure the sensitivity of
hearing.Audiometry deals with objective measurement of the
auditory organ. However a major difficulty is encountered when
we attempt to apply objective physical methods to measure
subjective sensation. While some parameters of hearing can be
assessed quantitatively (numerically), this is the exception and
very often we have to accept a qualitative assessment.
Hearing, like other sense organs, is an unusual organ from the
viewpoint of biophysics. The extreme sensitivity of the hearing
apparatus and its ability to discriminate significant sound signals
from superimposed background sound (also called noise) which
may be more intense than the signal of interest to the perceiving
subject are among some of the ways in which hearing is unusual.
The exceptional qualities of hearing are generally well known but
in some cases not very satisfactorily explored and explained. It is
known, for example, that the threshold sensitivity of the hearing
organ is betterthan the value of 10-12 W.m-2 in a fully sound
adapted healthy individual. This value represents

2. theinternationalstandard for the zero sound loudness level and
known as the conventional value of the auditory threshold (0 dB)
at the reference frequency of 1000 Hz.Air conduction tests the
entire auditory system. Bone conduction bypasses the
conductive mechanism, so it tests only the inner ear.There could
be various disorders in the various parts of the ear. Audiological
investigations help us to diagnose the nature of deafness and
localise the site of disorder. The method by which patient's
hearing sensitivity can be determined is termed as audiometry [1].
It helps in assessing the nature, degree, and probable cause of
the hearing impairment. In this technique, auditory stimuli with
varying intensity levels are presented to the person who responds
to these stimuli. The minimum intensity level of these stimuli to
which consistent responses are obtained is taken as the threshold
of hearing . Depending on this threshold, the patient s hearing
sensitivity can be estimated by obtaining an audiogram. An
audiogram is a plot of threshold intensity versus frequency. Then
the best-suited medical treatment or hearing aid or other assistive
devices can be prescribed. There are different audiometric
procedures depending on the stimuli used. An audiometer is an
instrument, which is used for carrying out these audiometric tests.
Tools Required:Hand , Screw drivers of Different Sizes.
Experimental procedure:
The dissection of Audiometer starts with removing of screws
at the left and right panels and after taking the bolts at the
back we get the back part .
At the back we see the mic1 mic2 and other connections . At
the middle we see three motherboards vertically and two
mother boards horizontally .

3. The three motherboards were fixed with an horizontal rod.
The vertical motherboard was fixed with pins.
There are H bridge rectifier and heat sink .To avoid ripples
we use 6 capacitors .
Discussion:
Product Architecture:

4. Geomtric Layout:
History:
It’s not well known that Alexander Graham Bell is generally credited with the invention of the
audiometer (a prolific inventor, his work also included the first metal detector and a device to locate
icebergs). Even less well known is the man who developed the first “modern” version of the
audiometer in 1899 – Carl E. Seashore. Seashore intended the device to measure “keenness of
hearing,” and his version formed the basis for devices commercialized by a company called Western
Electric.
By the 1920’s, technological advances had led to more modern systems capable of producing “pure
tones” via air circulation. Audiograms – diagrams illustrating hearing thresholds at given sound
frequencies – began appearing in medical journals in this time period, and were gradually
standardized. By the post-World War II era, automatic audiometers were printing out standardized
diagrams without the need for manual transcription by the administrator.
Suggested Improvements:
Try to make it more compatible ,the we can change the input keys.