iSEMcon EMX-7150 User manual

EMX-7150
single use microphone,
matched pairs, triples, quads
iSEMcon
Measurement Microphones
The FOH choice
PRODUCT INFORMATION
01-17

AT A GLANCE
Standard windshield included
High SPL capability
freefield calibration data
diffusefield calibration data*1
1/4" acoustical port
Long microphone body
reduces early reflection effects
All stainless steel body
Factory replaceable electronics &
capsule
O-Ring seal
Water tight connection
when using Neutrik*2 NC-3FX-HD
connector
*1: approximated by 90deg incidence
response
*2 The corporate names and names of
the products stated in this brochure are
trademarks or registered trademarks of
the respective companies.
The EMX-7150 is a ¼” microphone made
from stainless steel and using state of the
art water tight Neutrik*3 connectors hav-
ing a very accurate frequency response
combined with the capability to

measure high sound pressure levels up
to 145dBspl.
It is a low impedance measurement
microphone that can be operated from
12…52 V Phantom Power which is
available on most professional micro-
phone preamplifiers and professional
computer interfaces. With its mechani-
cally robust design it is well suited for
harsh environment use such as open
air sound reinforcement measure-
ments. Its class 1 frequency response
(NOTE: NOT A CLASS 1 MICROPHONE)
makes it predestined for room acous-
tics analysis including recording studios
and home theaters. It can normally be
used without the included freefield
calibration data file for compensation.
In this case take the individual calibra-
tion data as proof of its superb per-
formance.
TYPICAL APPLICATIONS
 Sound-power and sound-field analysis
 Industrial acoustics
 Room acoustics analysis
 Sound reinforcement
 Real time analyzers
FEATURES
 Frequency range 10Hz…20kHz
 Sensitivity 6mV/Pa typ.
 Dynamic range ~30… >140dBspl
 3% distortion limits >143dBspl typ.
 Calibration chart and calibration data
files included on CD/USB stick.
 IEC 61672-2013 class 1 frequency re-
sponse
 Dimensions: acoustic port dia.¼” (7mm)
 Microphone body 0.75” (19mm)
 Overall length 6” (152mm)
 Weight 0.3oz (75 grams)

PERFORMANCE ENVIRONMENTAL
Frequency Response Characteristic Free-Field Operating Temperature Range -10…+55° Polarization Voltage Prepolarized Storage Temperature Range -20…+70° Nominal Sensitivity @1kHz 6mV/Pa Operating Humidity Range 0…90%r.H. Sensitivity Temperature Drift <0.015dB/K Axial Vibration Sensitivity ~ 50dB Microphone Polarity Non-Inverting PHYSICAL Frequency Response calibrated 10…20.000 Hz Housing Material Stainless Steel Frequency Response IEC61672 –2013 class 1 *1 Sealing O-ring/Polyurethane/Epoxy Inherent Noise100-10000 Hz <30dB typ. Output Connector XLR male Max. SPL. (3% distortion limit) > 141dBspl Dimensions Ø ¼“(7mm) x 6“(152mm) Max. SPL. (3% distortion) typ. =143 dBspl Weight 0.3 oz (75g) Max. SPL. (3% THD) @ 12V Phantom >140 dBspl CONFORMITY IEC 61000-6-1;
ELECTRICAL SPECIAL FUNCTIONALITY
Output Impedance < 200 ΩVoltage Surge Protection 
Phantom Power 12…52Vdc EMC Noise Filter 
SPECIFICATIONS
Values for 23° Celsius and 48V Phantom Power

FREQUENCY RESPONSE
ISOBARS, typical

POLAR PATTERNS, typical

THD vs SPL, typical
k2, k3 and THD (blue/red/green)
THD vs SPL, typical
Equivalent Noise: FFT, 1/3 Octave, A-
weighted, ITU-R 468 RMS weighted
(magenta, blue, green, red)

CALIBRATION DATA FILE FORMAT
Human readable ASCII file: 1/12 octave www.iSEMcon.com freefield Sensitivity 5.88 mV/Pa @1kHz 10.00 -0.02 11.26 0.10 ………. 19992.19 0.93 ^ frequency (Hz) ^amplitude response (dB
THD , ref 1kHz

The temperature characteristics of the sensi- tivity of an electret condenser microphone depends on the electrical characteristics of the microphone capsule built-in impedance con- verter and signal conversion circuitry as well as the acousto-mechanical characteristics of the diaphragm equivalent stiffness. iSEMcon is one of the first microphone manufacturers disclosing the secret about the temperature behavior of electrets based measurement microphones.
TEMPERATURE STABILITY

1kHz
Tempera-
ture
-20°C 6,92
0°C 6,83
10°C 6,71
20°C 6,62
35°C 6,60
45°C 6,57
55°C 6,50
The range for the measurement was
set at -20° to 65° C which is more than
iSEMcon microphones are normally
used at. The most important tempera-
tures are 10 °C up to about 55°C
which covers indoor as well as open air
use. It will give you a good predictable
performance whether it is used in a
cold autumn night or if the hot summer
sun “burns” the microphone body.
The table below shows the microphone
sensitivity change @ 1kHz. The diagram
on previous page shows how tempera-
ture affects the frequency response
behavior of an EMX-7150 microphone.
The microphone capsule itself is the
part being responsible for most of the
temperature change. (see also: Tem-
perature characteristics of electret con-
denser microphones Acoust. Sci. &
Tech. 27, 4 (2006))
Microphone sensitivity vs. Temperature
typical

NEW MATCHING MICROPHONES
iSEMcon now offers matching stereo
pairs as well as matching triples and
quads within a consistent tolerance.
While matching microphones , it is cru-
cial to ensure that the frequency re-
sponse and sensitivity is identical
within a specified tolerance . Some of
our competitors state that their micro-
phones are matching or sell matching
pairs and you are not informed about
how those microphones might be dif-
ferent in frequency response and mi-
crophone sensitivity.
iSEMcon’s matching tolerance
To ensure realistic sound field meas-
urement and multi channel audio ex-
perience, each microphone is individu-
ally calibrated and selected to meet
our standard matching tolerance. The
matching tolerance is applicable within
the microphone’s entire frequency
range.
For the EMX-7150 the matching toler-
ance on frequency response is +/-
0.5dB and 1mV on microphone sensi-
tivity.
The matching process (1-4):
The first stage of testing begins with the
selection of microphone capsules. We
filter capsules being close in their overall
performance (frequency and sensitivity).
The second stage is the microphone
manufacture using those selected cap-
sules.
The third stage focuses on final testing of
each microphone. This includes the cali-
bration procedure (individual frequency
response measurement) as well as sensi-
tivity measurement at 12V, 24V

Matching curve for a EMX-7150 pair
Diagram A vs B vs class 1 and 2 class tolerances

and 48V Phantom power.
Finally we are selecting one reference
microphone (A) and compare the over-
all frequency responses of its potential
partners.
FOH: You measure and optimize the
acoustical sound field for the audience
together with SPL or better say Leq
monitoring….. Why not use one
matched pair for stereo recordings?
Matched sensitivity is important when
you want center instruments to be
heard from the center between your
stereo speakers, rather than shifted
slightly left or right of center. A level
mismatch also can change the musical
balance between orchestral instrumen-
tation. Of course, you can compensate
for microphone sensitivity differences
with your recorder's level controls or
mixer's pan pots but not for frequency
response mismatch.
Matched frequency response is impor-
tant for the sharpest possible imaging.
The more closely the stereo micro-
phones are matched in frequency re-
sponse, the better the image focus and
localization. For example:
Suppose the left microphone is 3 dB off
at 200 Hz relative to the right micro-
phone. For an instrument in the center
of the musical ensemble, its repro-
duced low frequencies will shift to-
ward the left, while mid frequencies
will remain in the center . Localization
for this instrument will spread or will
cause blurring between the real (mid
frequency) image and the phantom
(low frequency) image.
MATCHING PAIRS IN STEREO
RECORDING

CALIBRATION
Calibration prodecure step 1
Substitution Methode 500Hz … 20kHz
 Reference Speaker Measurement using
Reference microphone
 MLS Signal (Maximum Length Sequen-
ce) + Gating (No room response / re-
flections)
 Replacing Reference mic with EMX-
7150 microphone
 Calculating EMX-7150 frequency res-
ponse from impulse response data
Each microphone sold comes with its
individual calibration data. This includes a
calibration chart (pdf-file) as well as hu-
man readable calibration files for both,
freefield and diffusefield response.

Calibration prodecure step 2
 P r e s s u r e C h a m b e r M e t h o d
10Hz...500Hz
 Direct compare of EMX-7150 against a
Lab Standard Refernce Microphone
using sine sweep signal *1
*1 Freefield microphones as well as pres-
sure response microphones have the sa-
me frequency response behavior at low
frequencies.
60 dBspl LEVEL LINEARITY
Each microphone is SPL linearity checked
against class 1 tolerances (+/- 0,8dB) as
per IEC 61672-1 (2013)

APPLICATION NOTES
FREEFIELD vs. DIFFUSEFIELD USE
Only a small percentage of all acousti-
cal measurements are performed in a
well defined and/or well controlled
environment of an e.g. acoustical labo-
ratory –on the contrary most acousti-
cal measurements are done under not
really controlled conditions. Here are
some hints on how to use our micro-
phone.
Sound Fields:
Free field: There are no reflec
ting objects, only the
microphone influen
ces the sound field.
Diffuse field: There are many re
flecting surfaces or
sound sources so that
the sound waves arri
ve from all directions.
Pressure field: This is found in small
confined spaces like
sound calibrators.
Depending on the nature of the sound
field an appropriate microphone, which
is optimized for the sound field could
be selected. Unfortunately there are
many practical situations where the
sound field is not really of a well de-
fined type. This application note should
give you an idea on how to measure
with a free field response microphone.
The free field microphone is the most
common in use, chosen on tradition
but we should know about the sound
field.
The following picture shows both the
free field and the diffuse field response
of a free field microphone.

A microphone’s random (diffuse) inci-
dence response can be approximated by
measuring the 90º incidence response
relative to a single sound source (as per
B&K literature).
The diffuse field response is not easy to
measure, because it is not easy to gener-
ate a truly diffuse sound field over a wide
frequency range but there is a known
procedure to estimate the diffuse fre-
quency behavior of a free field micro-
phone.

From literature we know, that a micro-
phone’s random (diffuse) incidence
response can be approximated by
measuring the 90 deg incidence re-
sponse relative to a single sound
source.
While it is an approximation only iSEM-
con has measured the 90deg response
of many EMX-7150 microphones and
used the averaged data to evaluate a
19th order polynomial. This is now used
to derive the “diffuse field” response
from the microphones free field re-
sponse data.
Typical freefield measurement:
Speaker measurement. The micro-
phone should target to the sound
source (speaker).
Typical diffusefield meas-
urements:
Concert SPL monitoring
(normally at FOH), Room
Acoustics measurement
(RT60): the microphone
should not target to the
sound source. Let it target
to the ceiling. This is the
most practical way.

The EMX-7150 should not
be plugged or unplugged
into a mixer console or PA
system unless the input
channel is muted. If the sys-
tem does not have a muting option the
volume should be turned off. This
avoids loud popping noise that can
cause damage in speakers and/or af-
fect your hearing.
This electronic device should
be disposed separately from
your household waste at the
end of its lifetime. There are
various collection systems for
recycling in the European Union. For
further information please contact
your local authority or retailer where
you have purchased the product.
This microphone is a maintenance free
product but could require a recalibration
in case of a mechanical impact or perodi-
cal temperature cycling/use at the min
and max working temperature.
In an unlikely event of equipment failure,
please contact your local iSEMcon repre-
sentative or the iSEMcon factory located
in Germany ([e-mail]).
Unauthorised dismantling of the mic-
rophone will invalidate the warranty.
MAINTENANCE
ELECTRONIC WASTE
INSTALLATION

No Name Description 150010 EMX-7150 Bulk version: EMX-7150 microphone + WS-7XL windscreen + clamp w/ adapter
screw+ data-CD, mic in tube, polybag
800060 EMX-7150-CF1 EMX-7150 microphone + clamp w/ adapter screw + WS-7XL windscreen + 1/4" to
IEC 1/2" (13,2mm) calibrator adapter + calibration data on USB stick -pouch
800070 EMX-7150-CF2 EMX-7150 microphone + Shockmount w/ adapter screw + WS-7XL windscreen+ 1/4"
to IEC 1/2" (13,2mm) calibrator adapter + Calibration data on USB stick -Pouch
800080 EMX-7150-CF/MP 2x EMX-7150 microphone (MATCHED PAIR) + clamp w/ adapter screw + WS-7XL
windscreen , 1X 1/4" to IEC 1/2" (13,2mm) calibrator adapter + calibration data on USB stick - Pouch
800081 EMX-7150-CF/MT 3x EMX-7150 microphone (MATCHED TRIPLE) + clamp w/ adapter screw + WS-
7XL windscreen , 1X 1/4" to IEC 1/2" (13,2mm) calibrator adapter + calibration data on USB stick - pouch
800082 EMX-7150-CF/MQ 4x EMX-7150 microphone (MATCHED QUAD) + clamp w/ adapter screw + WS-7XL
windscreen , 1X 1/4" to IEC 1/2" (13,2mm) calibrator adapter + calibration data on USB stick - pouch
ORDERING INFORMATION