1/2-inch Microphone/ Preamplifier

MI Series

 

The MI-1271 1/2-inch back electrets-type microphone that does not require bias power has been newly added. The environmental stability against temperature and humidity has been improved by laser welding fixation of titanium vibrating membrane compared with conventional models. Also, there are MI-1235 which emphasizes on a wide frequency range and MI-1433 which realizes a similar environmental resistance performance at a low price. MI series microphone is used in combination with the preamplifier and the microphone.

MI-1271

製品写真(MI-1271  1/2インチ計測用マイクロホン)

MI-1271 is high performance microphone which conforms to IEC 61094-4 Type WS2F.
By adopting the titanium vibrating membrane, it realizes long-term stability and wide frequency range of 1 Hz to 20 kHz. It can be used in wide temperature range of -30℃ to +80℃. Even though it is back electrets-type, it is effective for low noise measurement of self noise level 14 dB (A-weighting).

MI-1235

MI-1235 is best to be used as measurement and analysis for environmental noise, architectural acoustics, and radiated sound from electrical/mechanical instruments. And it has a wide frequency range of 10 Hz to 20 kHz.
It is precision microphone used with the MI-3111 microphone preamplifier.

 

MI-1433

MI-1433 is excellent for environmental noise measurement with frequency range of 20 Hz to 8 kHz. It is general microphone with low cost used with the MI-3111 microphone preamplifier.

 

 

 

 

MI-1271/3170 Product video (YouTube)

 

System Configuration

Each product in the analyzer section in the below configuration is linked to its own page.



Specifications

Model name

MI-1271 MI-1235 MI-1433
Response type Free sound field
Positive voltage 0 V
Sensitivity (1 kHz) -26 dB±1.5 dB re. 1 V/Pa
50 mV/Pa (1 kHz)
-29 dB ±3 dB re. 1 V/Pa
36 mV/Pa (1 kHz)
Capacitance (1 kHz)

12 pF

(Representative value)

13 pF
(Representative value)
Frequency range
(1 kHz at standard)
1 Hz to 20 kHz
(±2 dB)
10 Hz to 20 kHz
(+1.5 dB、-5 dB)
10 Hz to 10 kHz
(+1.5 dB、-2 dB)
20 Hz to 8 kHz
(±2 dB)
Effective load volume 359 mm3 260 mm3 239 mm3
Maximum sound pressure level (Total harmonic distortion 3 %)

135 dB

(when using MI-3170)

135 dB(when using MI-3111)
141 dB(when using MI-3170)

Intrinsic noise level

(A-weighting)

14.0 dB (representative value) 
(when using MI-3170)
19.0 dB (representative value)
(when using MI-3111)

Static pressure characteristics

(at 250 Hz)

-0.013 dB/kPa

(representative value)

-0.03 dB/kPa or less

Temperature characteristics

(at 250 Hz)

+0.005 dB/K

(representative value)

+0.009 dB/K or less

Humidity characteristics

(at 250 Hz)

-0.0004 dB/%

(representative value)

-0.001 dB/% or less
Operating temperature range -30 to +80 ℃ -10 to +50 ℃
Operating relative humidity range

0 to 90 %

(with no condensation)

30 to 90 %
(with no condensation)
Storage temperature range -40 to +70 ℃ -20 to +60 ℃
Storage relative humidity range

0 to 90 %

(with no condensation)

10 to 90 %
(with no condensation)
Weight Approx. 6 g
Outer dimension φ13.2 mm × 16.9 mm φ13.2 mm × 13.7 mm φ13.2 mm × 13.5 mm

Preamplifier

MI-3170

製品写真(MI-3170 1/2インチ計測用マイクロホンプリアンプ)

MI-3170 is a preamplifier for 1/2-inch back-electret type condenser microphone. Adopting the CCLD method and BNC connector, various types of CCLD accepted amplifier, analyzer and data recorder can be connected directly.
It can be used in wide operating temperature range (-30 to +80℃) when combined with the MI-1271 high-performance microphone. It is a low noise preamplifier that covers the measurement range of ultra low frequency of 1Hz.

 

MI-3111

製品写真(MI-3111 1/2インチ計測用マイクロホンプリアンプ)

MI-3111 is a preamplifier for 1/2-inch back-electret type condenser microphone. It is CCLD and BNC connector type.
It is a general preamplifier used with the MI-1235/MI-1433 microphone.

Specification

Model name MI-3170 MI-3111
Applicable microphone MI-1271 /1235/1433
(Discontinued)MI-1233/1234/1431/1432
MI-1235/1433
(Discontinued)MI-1233/1234/1431/1432
Insertion loss 0.15 dB (at 1 kHz)(representative value) 1.0 dB(representative value)
Frequency range

10 Hz to 40 kHz

(+0.1 dB、-0.2 dB、1 kHz as reference)
1 Hz to 40 kHz

(+0.1 dB、-1.5 dB、10 Hz as reference)

10 Hz to 20 kHz
(±1.0 dB、1 kHz as reference)
20 Hz to 20 kHz
(±0.6 dB、1 kHz as reference)
Input impedance 40 GΩ 5 GΩ±15%

Intrinsic noise

(effective voltage)

A-weighting: 3.3 μV or less
(Sound pressure conversion 8 dB)
MI-1271 sensitivity: -26 dB re. 1 V/Pa
A-weighting: 5.0 μV or less
(Sound pressure conversion 17 dB)
MI-1271 sensitivity -26 dB re. 1 V/Pa
Total harmonic distortion
0.0316 % or less
(Input frequency 1 kHz, Input effective voltage 1 V)
0.1 %(-60 dB) or less
(Input frequency 20 kHz, Input effective voltage 1 V)
1 % or less
(Input frequency 1 kHz, Input effective voltage 3.15 V)
DC bias voltage 12 V ± 2 V 8 V ± 1 V
Maximum output voltage ±8 V (Peak) (driving power 24 VDC, 4mA)
Sound pressure conversion135 dB
(Sensitivity 50 mV/Pa when using microphone)
±5.6 V (peak) (driving power 24 VDC, 4mA)
Sound pressure conversion 135 dB
(Sensitivity 35 mV/Pa when using microphone)
Operating temperature range -30 to +80 ℃ -10 to +50 ℃
Operating relative humidity range 0 to 90 %(not including microphone) 30 to 90 %(not including microphone)
Storage temperature range -40 to +70 ℃ -20 to +60 ℃
Storage relative 0 to 90 %(not including microphone) 10 to 90 %(not including microphone)
Power supply CCLD
2 to 4.5 mA、DC 18 to 26 V
CCLD
0.5 to 5 mA、DC 15to25 V
Applicable connector C02(BNC)
Weight Approx. 35 g (not including microphone) Approx.25 g(not including microphone)
Outer dimension φ12.7 mm × 80.5 mm φ12.7 mm × 63.5 mm
Accessory

Protection cap for input connector×1
Microphone holder (MI-0301)×1
Instruction manual x1

Protection cap for input connector×1
Microphone holder (MI-0301)×1
Instruction manual x1
Extension cable MX-1000 series (recommended), MX-2000 series MX-2000 series (recommended)

 

Connection cable (both terminals are BNC connector)

Model name Outer dimension Length Operating temperature range
MX-1001 Signal cable for low/ high temperature
MX-1000
1.5 m -30 to +80 ℃
MX-1005 5 m
MX-1020 20 m
MX-2001 MX-2000 1.5 m 0 to +60 ℃
MX-2005 5 m
MX-2020 20 m


Revised:2017/06/30



 

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