HomeProductsSensorsMicrophone kit1/4inch, Free-field, 20kHz, IEPE

SS 740

1/4inch, Free-field, 20kHz, IEPE
The SS 740 is a free field measuring microphone for 1/4 inch electret microphones, which is used to measure the undistorted true sound pressure of the microphone before it is placed into the sound field.
The SS 740 is positioned for its high sensitivity, suitable for applications such as conventional acoustic testing, microphone array testing, and the microphone and preamplifier are built in one piece and are not removable.
With MegaSig PM 0083 and other IEPE signal conditioning to achieve the best test results.

Description
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Description

Specifications

Parameter	Value
TEDS Function	No
Dimensions	1/4inch
Sound Field Type	Free field+Electret
Polarization Voltage	0V（Pre-polarized）
Frequency Response	20Hz - 20kHz ± 2dB
Dynamic Range	34dB（A）-125dB （1000 Hz 失真<3%）
Noise Floor	34dB（A）
Sensitivity mV/Pa (dBV/Pa)	50mV (-26.0dB) ± 2dB
Maximum Output Voltage	1.8V
Output Impedance	<50Ω
Supply Power	2mA - 20mA （Typical4mA）
Connector Type	SMB
Operating Temperature	-10°C to 40°C
Temperature Coefficient	/
Humidity Coefficient	<0.1dB（10%- 60% no condensation）
Relative Humidity	10%- 60% no condensation
Static Pressure Coefficient	-0.01dB/kPa

Specifications

Types of Acoustic Fields	Free Field
Polarization voltages	0V（Prepolarized）
Frequency range	20Hz – 20kHz ± 2dB
Dynamic range	34dB（A）-125dB（1000 Hz THD<3%）
Background noise	34dB（A）
Sensitivity mV/Pa(dBV/Pa)	50mV (-26.0dB) ± 2dB
Maximum Output Voltage	1.8V
Output Impedance	<50Ω
Power Supply	2mA - 20mA（typical 4mA）
Pressure Equalization Method	Post-equalization
Connection	BNC
Temperature range, operation	-10℃ to 40℃
Temperature range, storage	Temperature：25℃±5℃，Humidity：50%±15%RH（Ensure the long-term stability of the sensor）
Humidity range non condensing	10 - 60% without condensation
Humidity coefficient	<0.1dB

Dimensions：mm

Types of Acoustic Fields	38.5mm
Diameter (excluding protective grille)	7mm

The measuring microphones we produce are precision sensors, and all aspects related to production are strictly controlled, including material selection, production processes, testing control, and production environment.

图片1.png After years of continuous improvement, we now use special nickel alloy materials as the core material for the diaphragm. Compared to other alloy materials, it exhibits higher sensitivity, lower distortion rate, and more stable long-term performance. The front body of the microphone is made of stainless steel, ensuring that the entire microphone maintains extremely robust structural characteristics even under various assembly conditions.

We adopt advanced production processes and fully automated precision machining equipment, which significantly reduces the accuracy errors caused by secondary clamping in traditional machining equipment. This greatly enhances the dimensional consistency, geometric accuracy, and overall quality stability of the products, providing reliable technical support for demanding application scenarios.

At the same time, we employ extremely rigorous testing and control measures, conducting quantitative testing on any links that may lead to product quality issues, and implementing test sequence control to prevent skip-station situations. The comprehensive MES control enables all data to be traceable, ensuring a high degree of consistency in sensor quality.

The entire production process of all our microphones is strictly carried out in a dust-free workshop, which can minimize the amount of dust in the air, thus creating a stable and pure working environment for the sensors. This ensures a long and stable lifespan for the sensors and maintains their excellent performance throughout daily use.