HomeProductsSensorsMicrophone kit1/4inch, Free-field, 100kHz, IEPE

M 645+A 811

1/4inch, Free-field, 100kHz, IEPE
M 645+A 811 is a microphone set which is prepolarized, 1/4 inch, for free-field measurement, Ideally for production test.
All the microphones are going through solid environmental testing, which includes high temperature ageing and high humidity ageing.

Description
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Description

Specifications

Parameter	Value
TEDS Function	No
Frequency Response	10 - 100kHz ±3dB 20 - 50kHz ±2dB
Dimensions	1/4inch
Distortion	＜0.1%
Sound Field Type	Free field
Operating Current	Typical 4mA
Polarization Voltage	0V（Pre-polarized）
Connector Type	microdot接头
Applicable Temperature	-35°C to 85°C
Dynamic Range	37dB（A）-155dB（1000 Hz 失真<3%）
Length	/
Noise Floor	37dB（A）
Sensitivity mV/Pa (dBV/Pa)	5mV (-46.0dB) ± 2dB
IEC 61094-4 Type	WS3F
Maximum Output Voltage	5.6V
Output Impedance	<50Ω
Supply Power	2mA - 10mA（Typical4mA）
Pressure Equalization Method	Post-equalization
Operating Temperature	-30°C to 85°C
Temperature Coefficient	-0.012dB/℃
Humidity Coefficient	<0.1dB（0%- 90% no condensation）
Relative Humidity	0-90% no condensation
Static Pressure Coefficient	-0.01dB/kPa

Specifications

Types of Acoustic Fields	Free Field
Polarization voltages	0V（Prepolarized）
Frequency range	10 - 100kHz ±3dB 20 - 50kHz ±2dB
Dynamic range	37dB（A）-154dB（1000 Hz THD<3%）
background noise	37dB（A）
sensitivity mV/Pa(dBV/Pa)	5mV (-46.0dB) ± 2dB
Maximum Output Voltage	5.6V
Output Impedance	<50Ω
Power Supply	2mA - 20mA（typical 4mA）
Pressure Equalization Method	Post-equalization
Connection	Micordot(M5)
Temperature range, operation	-30℃ to 85℃
Temperature range, storage	Temperature：25℃±5℃，Humidity：50%±15%RH（Ensure the long-term stability of the sensor）
Humidity range non condensing	0 - 90% no condensation
Humidity coefficient	<0.1dB（no condensation）

Typical frequency response curve

Dimensions：mm

M 645+A 811.png

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.