Brüel & Kjær i714 Operation manual

HEADQUARTERS: Brüel & Kjær Sound & Vibration Measurement A/S •DK-2850 Nærum •Denmark
Telephone: [phone] •Fax: [phone] •www.bksv.com •[email protected]
Local representatives and service organisations worldwide
The i714 Portable Audiometer
Calibration System is an easy,
flexible and reliable solution for
automated calibration of audiome-
ters to IEC and ANSI standards.
Audiometer certification is the
primary focus, but the system is
designed to accommodate the
everyday needs of hospitals and
clinics as well as those of calibra-
tion and metrology laboratories.
Other fields of use are audiometer
R&D and factory production test-
ing.
The system is build around the
powerful sound level meter and
analyzer Type 2250. It utilizes the
precision of the Class 1 measuring
instrument, experience in calibra-
tion and simplicity of use. The
system performs the tasks rang-
ing from basic standard audiome-
ter testing with fully automated
procedures to advanced custom-
ized tests.
The Type i714 with integrated
database takes care of test proce-
dure execution as well as all
house-keeping data including cli-
ent e-mail reminder for next cali-
bration.
The calibration Software is not
limited to any specific brand or
type of audiometer as long as the
audiometer complies with relevant
ISO standards.
The interface with variety of
audiometers is secured by using
Brüel & Kjær family of top-class
couplers, artificial ear Type 4152 /
4153 and artificial mastoid Type
4930. The system can be config-
ured for the in house calibration
services or production tests as
well as for the use in the field,
without compromising neither ac-
curacy nor stability.
Portable Audiometer
Calibration System
Type i714
PRODUCT DATA
Uses
 Calibrate any type of audiometer fulfilling IEC
60645 family of standards.
 Calibrate Headphones, Inserts, HF phones, Bone
Oscillators and Tympanometers
Features
 Calibration procedures based on ISO 61389 and
ISO 318 standards for air conductive and bone
conductive transducers.
 Automatic correction for microphone and artificial
mastoid sensitivity deviations.
 Multiple test procedures.
 Semi- or fully automated procedures execution.
 Data on operators, customers, audiometers, tests
and test equipment is managed in one database.
 Data can be retrieved by a range of query pa-
rameters.
 Tracking of calibration equipment inventory and
calibration date.
 Audiometer adjustment instructions
 Customized calibration reports
 Calibration reminder via e-mail.
USES AND FEATURES
… Easy, flexible
and reliable

Audiometer Calibration
The system calibrates audiometers
using an ear simulator system. It
includes an artificial ear for testing
air-conduction hearing mecha-
nisms. This device consist of a
calibrated microphone with an
associated coupling volume open
on one side allowing application of
headphones when testing.
For testing bone-conduction
hearing mechanisms, an artificial
mastoid is utilised. This device
uses a series of rubber layers to
couple the bone-vibrator to a
force transducer. The device
mimics the way in which sound is
transferred through the mastoid
part of the human temporal bone,
to which the bone-vibrators are
applied when testing.
The purpose of any calibration
measurement is to check that the
measurement equipment is meas-
uring correctly. Regular testing
and calibration of an audiometer is
required to maintain maximum
measurement accuracy.
For absolute acoustic calibra-
tion the audiometer should be
calibrated using an artificial ear, a
special measuring microphone
designed for that purpose and a
known sound pressure level.
Accurate and reliable measure-
ments are fundamental to charac-
terise and quantify hearing loss,
and consequently for selection of
hearing aids and for general
health and safety monitoring.
Prober calibration ensures that the
measurements are consistent, no
matter where the they are carried
out.
i714
Portable Audiometer Calibration System
Figure 1.
Main menu of the i714 software
—a simple and intuitive user interface with all functionalities
Calibration..?
2
The basic aim of acoustic
audiometer calibration is to
define the audiometric zero for
the chosen earphone. This can
be performed using human
volun-teers or an artifical ear.
There are different types of
audiometer output transdu-
cers:
1. Ear phones
2. Bone vibrator
3. Loud speaker (free-field)
Output transducers for audio-
meters cannot be replaced or
changed without calibrating
the whole equipment.
Calibration of the audiome-
ter involves calibration of the
audiometer proper, of ear pho-
nes, and of bone vibrators.
The calibration of bone
vibrators is the same as for
earphones except for the
measuring device which is
different.
On/off
Figure 2.
Set-up of the i714
Portable Audiometer
Calibration System

i714 Portable Audiometer Calibration System
3
Acoustic Analyzer
The i714 Portable Audi-
ometer Calibration System
is based on the Type 2250
Hand-held Acoustic
Analyzer. Type 2250 is a
compact and robust hand-held
instrument, which can host a
number of software modules.
Sound Calibrator
Sound Calibrator Type 4231 is a
pocket-sized, battery operated
class 1 sound source. The
calibration frequency is 1000Hz (the
reference frequency for the standardised
international weighting networks) with a
calibration pressure of 94 ±0.2 dB re 20 μPa is
equal to 1 Pa or 1N/m2.
Artificial Ear
Type 4152
Artificial Ear Type 4152
has been designed for
measurements in the
audiometric and related
fields. The primary function is
the calibration of supra-aural
earphones used in audio-metry in complaince with
IEC 60318-2.
The Artificial Ear Type 4152 consist of an acoustic
coupler, a main housing containing the sockets for
the connection of a condenser microphone and a
base plate with a mechanism for clamping the
object being tested. The Artificial Ear is isolated
from shock and vibration by means of three soft
rubber feet.
Artificial Ear Type 4153
Artificial Ear Type 4153 fulfils the requirements of
IEC 318 and has an acoustical impedance basically
similar to that of the human ear and allows circum-
aural earphones calibration. The acoustic coupler
contains three volumes (V1 = 2.5cm3, V2 =
1.8cm3 and V3 = 7.5cm3) acoustically connected in
parallel by means of a narrow annular
slit and four parallel holes.
Couplers
The couplers supplied with the artificial ear consist
of a 2cm3Coupler DB 0138 in accordance with
IEC126 and ANSI S3.7–1973 for measurements on
hearing aid earphones, and a 6cm3Coupler DB
0913 which fulfils the requirements of the
NBS 9A Coupler (United States National
Institute of Standards and Technology)
and the ANSI S3.6–1969 and IEC 303
Coupler for measurements on headphones.
Microphone Type 4144
Type 4144 is a 1″pressure-field
microphone and the pressure
frequency response is flat over a
wide frequency range. Hence no
correction is needed to the pressure response
below 8 kHz. The use of pressure-field microphones
is recommended where measurement of the local
pressure is of interest, for instance for coupler
measurements. The stability of Type 4144
combined with its low inherent noise and high
sensitivity makes it the perfect choice for coupler
measurements.
Artificial Mastoid
Artificial Mastoid Type 4930 is designed for the
calibration of bone conduction hearing aids and
bone vibrators used in audiometry. It mechanically
simulates the human head, incorporating a built-in
force transducer to monitor the output of the
device to be calibrated. The
artificial mastoid
ensures
longterm
stability and
accurate
correspon-
dence with the
mechanical
characteristics
of the human
mastoid.
System Instrumentation
The calibration system is based on Hand-held Acoustic Analyzer
Type 2250 and the Audiometer Calibration Software i714.
Microphone Type 4192
Type 4192 is a ½″pressure-field
microphone designed for high-precision
coupler measurements. Being externally polarized,
Type 4192 must be used with a classical
preamplifier. Externally polarized microphones
may be used at higher temperatures without
severe changes in sensitivity.

System Set-up
The Portable Audiometer Calibra-
tion System comes in a robust and
handy carrying case containing all
instruments, cables and adaptors
needed for testing and calibrating
audiometers—all needed in addi-
tion is a PC and a USB or LAN con-
nection.
The calibration system is set-
up by connecting the relevant
components and the instrument to
be calibrated into a measurement
chain. The audiometer under test
is connected via serial or USB
interface.
The set-up is configured ac-
cording to the options of the sys-
tem (xxxx-100 or xxxx-200, and
optional accessories at hand) and
to tests to be performed (see fig-
ure 2 and 3).
From unpacking to reporting a
basic calibration—including system
calibration—takes only 10 min-
utes.
Calibration Made Easy
Step by step the calibration soft-
ware guides the operator through
the preparation procedure—all in
an intuitive and logical order. Dur-
ing calibration, only the audiome-
ter is operated by calibration tech-
nician—the 2250 is controlled
from software.
Client Data
Data management is a critical part
of the calibration process and a
strong feature of the calibration
software. Measurement data, re-
ports, customer data, inventory
data, audiometer data, proce-
dures, corrections for headphones,
vibrators, microphones, mastoids
and operators are handled by SQL
database.
It is of major benefit to have all
data stored in a well-defined and
organised form, which facilitates
retrieval, editing and updating. An
additional safety feature is the
regular software notification to
produce a database back-up– in
case of computer failure all data
are preserved.
Prior to starting the actual cali-
bration, the operator must enter
customer information, select cali-
4
Portable Audiometer Calibration System i714
Easy,
flexible,
& reliable
The i714 Portable
Audiometer Cali-
bration System:
 reduces typing
errors by avoi-
ding manual data
entering
 reduces the time
needed for audio-
meter calibration
 prevents errors
caused by incor-
rect or ignored
corrections for
microphone or
mastoid
The system includes
a professional data-
base for:
 Customers
 Audiometers
 Procedures
 Reports
 House keeping
data
 Instrumentation
 Corrections and
reference values
Set-up the calibration system by connecting the relevant
components and the instrument to be calibrated into a
measurement chain.
Audiometer Calibration
in 9 simple Steps...
Start
Finish
Connect
equipment
Select client and associated audiometer from database.
If customer does not exist in database enter information including
audiometer and accessery data (type and serialno. etc).
Select calibration test or combination of calibration tests.
Enter temperature, humidity and air pressure - data obtained
from public sources.
Calibrate the measurement chain. Use the reference sound
source and include corrections for microphone and mastoid
obtained from an independent calibration laboratory.
Microphone chain sensitivity correction value is defined and
saved for each calibration.
Calibrate the audiometer. The calibration consists of 3 steps:
1. Calibration - deviations are calculated: the difference between
expected values and measured values.
2. Adjustment - the audiometer is adjusted to meet expected
values.
3. Recalibration, to ensure the correctness of the adjustment.
Use a query to retrieve calibration results from the database and
generate a report using a predefined template.
Calibrate
audiometer
Adjust
audiometer
Recalibrate
audiometer
1
Enter
client data
Select
procedure
Enter
atmospheric data
Calibrate
system
Create
report
9
6
5
4
3
2
7
8

bration procedure and specify in-
struments used. The client and
associated audiometer is selected
from the database. If customer
does not exist already in the data-
base, information is entered, in-
cluding audiometer and accesso-
ries data (type, serial-number
etc.).
The acoustic analyzer is recog-
nized by its serial number and
even more importantly by in-
stalled software (Active Tem-
plate). Most frequently used stan-
dardised headphones and vibra-
tors are available in the database
as default. Additional equipment
can be added by the user and cor-
rection values entered as re-
quired.
Microphone and mastoid cali-
bration corrections can be im-
ported from a USB key or entered
manually. Example of correction
graph is seen on figure x.
Procedure
An audiometer calibration task
incorporates several tests to be
selected depending on the type of
audiometer. All acoustic admit-
tance instruments use a probe
tone that must be calibrated for at
least frequency, SPL and distor-
tion.
The operator can select from a
range of tests:
 Pure tone (Air and Bone con-
duction level)
 Masking level (Narrow band)
 Masking level (Broad band)
 Attenuator linearity
 Frequency
 Total Harmonic Distortion
(THD)
 Narrow band cut-of frequencies
and bandwidth
 Free-field calibration
 Tympanometer calibration
One, some or all supported proce-
dures can be included in the cali-
bration task. Several procedures
can be merged into one procedure
(e.g. Pure tone first, Insert second
and Mastoid third).
Each set of tests is user-
defined, meaning that the opera-
tor can select frequencies at which
the tests are executed. All tests
are compared to limit values de-
fined by the user (in reference to
standards in question).
Corrections for used transducer
(microphone and/or mastoid) are
automatically read from the data-
base and taken into account for
calculation of the expected result.
All calculations are performed
by the i714 software and pre-
sented in a table as well as
i714 Portable Audiometer Calibration System
5
Figure 4.
A new client is added to the data-
base—client data can be reused
for other audiometers or when
next calibration is due
Figure 3.
The system software
guides you through all
steps of the calibration
procedure

6
Portable Audiometer Calibration System i714
graphically to
provide over-
view.
During pure tone
level calibration,
THD and fre-
quency are si-
multaneously
measured and
calculated.
Atmospheric
Data
The environ-
mental condi-
tions of the cali-
bration have to
be documented.
The levels of
temperature, air
humidity and air
pressure are en-
tered and will be included in the
final calibration report. These data
can be obtained from public
sources.
System Calibration
Traceability of measurement re-
sults is an integral part of the cali-
bration procedure. Traceability is
obtained by measurement chain
calibration at the beginning of
each audiometer calibration. Type
4231 is used as the reference
sound source producing 94dB at
1kHz—the software automatically
includes corrections for micro-
phone and mastoid obtained from
an independent calibration labora-
tory. The microphone chain sensi-
tivity correction value is defined
and saved for each completed
calibration. The i714 Software
Figure 5.
Microphone calibration corrections example
—Brüel & Kjær Type 4144
Figure 6.
Audiometer calibration in progress
- coloured dots indicate measurement status

7
i714 Portable Audiometer Calibration System
constantly moni-
tors the validity
of calibration
equipment in
use.
Calibration
can start as
soon as these
conditions for
correct calibra-
tion documenta-
tion are fulfilled.
Calibration
When all rele-
vant data are in
the database, it
is only a matter
of selecting the
calibration
equipment and
the audiometer
to be tested,
and calibration
is started.
The calibration of an audiome-
ter is performed in three steps:
1. Calibration - deviations are cal-
culated: the difference between
expected values and measured
values.
2. Adjustment - the audiometer is
adjusted to meet expected val-
ues.
3. Recalibration, to ensure the
correctness of the adjustment.
Online guidance eases the calibra-
tion and prevents the operator
from missing important steps or
taking incorrect actions. Each time
the operator needs to intervene
when calibration in progress, a
window with clear and instructive
information appears.
Any deviation exceeding limit
value displays an information win-
dow with an option to repeat or
accept the result. Results which
are out of tolerance limits get red
light in front of the step in ques-
tion. During semiautomatic cali-
bration, only the audiometer is
operated by calibration technician.
Intervention with Type 2250 is not
needed at all—it is controlled from
the software.
The i714 Software constantly
monitors the calibration validity of
client audiometers and automati-
cally sends out a notice on expired
calibrations at start-up or on re-
quest.
Reporting
Calibration results are saved in
the database and available for
creating report or just to be
viewed on the screen. A query
function provides capability to re-
trieve only the calibrations fulfill-
ing specific criteria.
Selected calibrations can be
examined on the screen or sent to
Figure 7.
Audiometer adjustment
instructions
Figure 8.
Reporting example
—part of calibration
certificate

Excel or Word using either a pre-
defined or customer defined re-
porting template.
Free-field Calibration
and Booth Verification
Mesurements for free or quasi-
free sound fields are specified by
ISO 8253-2. The standard
describes the characteristics of
free-field and diffuse field
characteristics and the procedures
and conditions of use for sound
field audiometry,
The loudspeaker should be
head-height of the seated listener,
and directed towards the
reference point. In absence of the
test subjct the sound pressure
levels 0.15 m above, below and to
the left and right of the reference
point should not vary by more
than 1 dB from those predicted by
the inverse square law (see figure
9.)
Tympanometer Calibration
The tympanometer should be
tested regularly, at least once a
day, preferably with each new
patient, and calibration data
included in the case.
The tympanometer is measur-
ing the acoustic immittance of the
ear as a function of ear canal air
pressure. Two measures require
calibration on the unit: air
pressure and physical volume.
Often the air pressure is calibrated
automatically at start-up.
To calibrate the physical
volume the calibration cavity is
installed on the probe tip. The
tympanometer should be tested
on a daily basis, e.g. With each
new patient to include calibration
data in the case.
ANSI S3.39-1987 requires that
three calibration cavities (0.5, 2.0,
and 5.0 cm3) be provided with
each instrument.
Portable Audiometer Calibration System i714
8
Figure 9.
System set-up for free-field
audiometer calibration or
audiometric test room / booth
verification.
On/off
+20dBOn/Of
f

i714 Portable Audiometer Calibration System
9
i714 -100 System
The Portable Audiometer Calibration System comes in two
standard configurations, which both comply with IEC
60645:
Xxxx-100 With Artificial Ear Type 4152 for audiometers
with supra-aural earphones or inserts according to ANSI
53.7-1955 and IEC 60318-3-5.
Xxxx-200 Like xxxx-100 , but with an additional Artificial
Mastoid with bone vibrators according to ANSI S 3.13
and IEC 60373-1990-01
Optional accessories:
Artificial Mastoid Type 4930 including Pressure Measure-
ment Microphone Type 4192 for testing audiometers
with circum-aural earphones.
Coupler Type 4946 with an Adaptor Type WA-1704 for
audiometers with insert earphones according to IEC
60318-4 for high frequency up to 16 kHz.
The Type i714-100 system consists of the following com-
ponents:
 2250-H Precision Sound Level Meter loaded with BZ
7222 (basic functionality) , 7223 (1/3 Octave analysis)
and 7230 (Narrow Band analysis (FFT)) conforming with
the following National and International Standards:
- IEC 61672 – 1 (2002 – 05), Class 1
- IEC 60651 (1979) plus Amendment 1 (1993– 02)
and Amendment 2 (2000–10), Type 1
- IEC60804 (2000–10), Type 1
 Optional BZ 7223 for 1/3 Octave analysis or BZ 7230 for
 i-714 Calibration software
 4152 Artificial Ear
 4144 1” Pressure Measuring Microphone
 4930 Artificial Mastoid
 4231 Sound Calibrator
 AO-0441-D003 10 pin Microphone cable, 0,3m
 AO-0038-D012 Super low noise cable, 10-32 UNF to 10-
32 UNF, 1,2m
 JJ 2617 Input adaptor, ½” Microphone to microdot
 DB 0962 Adaptor, to mount 1" microphone on 1/2" pre-
amplifier (included with 4152)
 KE xxxx Carrying case
i714 Software
EN 60645-1 2002 Electroacoustics - Audiological equipment
- Part 1: Pure-tone audiometers
ISO 389 Acoustics - Reference zero for the calibration of
audiometric equipment
EN 60318-3 2002 Acoustic coupler for the calibration of
supra-aural earphones used in audiometry.
PC Requirements
Operating System:
Windows® XP, Windows®Vista, Windows®7,
(Microsoft®.NET framework)
Recommended PC:
Pentium® III (or equivalent) processor, 128 MB RAM,
SVGA graphics display/adaptor, sound card, CD ROM
drive, mouse, USB, Windows®7
ORDERING INFORMATION

10
Please, contact your local
Brüel & Kjær representative for more information:
EXPORT SALES, MARCH 2011
SOUND AND VIBRATION
- CONTACT BRÜEL & KJÆR
Brüel & Kjær is a global company with
local representations and service
organisations worldwide.
Brüel & Kjær
Sound & Vibration Measurement A/S
Export Sales
Skodsborgvej 307
DK-2850 Nærum, Denmark
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
www.bksv.com
Portable Audiometer
Calibration System Type i714
Benefits:
Truly portable-easy to carry
 Use to use-no special skills required
 Automated calibration and reporting
On-line calibration instructions
 Automated correction of all instruments
 Traceable measurements and validity
monitoring
 Easy data-handling– storage and retrieval
 Compliance to standards IEC 60645, 389
and 8253
 Full flexibility for professional use