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MPA 668-812

Explosion proof certified specialized microphone k
MPA 668-812 free field measurement microphone kit is a special microphone kit with explosion-proof certification, which meets the requirements for use in hazardous areas and explosive environments and can ensure safe use in hazardous gas environments; It consists of a microphone MP 668 and a preamplifier MA 812, with the microphone and preamplifier detachable; Among them, MP 668 is a 1/2-inch pre polarized free field measurement microphone used to measure the undistorted true sound pressure of the microphone before it is placed in the sound field.
The MA 812 preamplifier is a preamplifier powered by a constant current source, characterized by high input impedance, low background noise, and a wide frequency response range. It can be used in conjunction with the MP 668 measurement microphone. The output interface adopts BNC connectors, and the main body is made of stainless steel material, which ensures good toughness and long-term storage

Description
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Description

Specifications

Parameter	Value
TEDS Function	No
Dimensions	1/2 inch
Sound Field Type	Free field
Polarization Voltage	0V（Pre-polarized）
Frequency Response	3.15Hz – 20kHz ± 2dB 12.5Hz – 10kHz ± 1dB
Dynamic Range	17dB（A）-135dB （1000 Hz 失真<3%）
Noise Floor	17dB（A）
Sensitivity mV/Pa (dBV/Pa)	50mV (-26.0dB) ± 3dB
IEC 61094-4 Type	WS2F
Maximum Output Voltage	5.6V
Output Impedance	<50Ω
Supply Power	2mA-20mA（Typical 4mA）
Pressure Equalization Method	Post-equalization
Connector Type	BNC
Operating Temperature	-20°C to 60°C
Temperature Coefficient	/
Humidity Coefficient	<0.1dB（10%- 90% no condensation）
Relative Humidity	10%- 90% no condensation
Static Pressure Coefficient	/

Specifications

Types of Acoustic Fields	Free Field
Polarization voltages	0V（Prepolarized）
Frequency range	3.15Hz – 20kHz ± 2dB 12.5Hz – 10kHz ± 1dB
Dynamic range	17dB（A）-135dB（1000 Hz THD<3%）
Background noise	17dB（A）
Sensitivity mV/Pa(dBV/Pa)	50mV (-26.0dB) ± 2dB
Maximum Output Voltage	5.6V
Output Impedance	<50Ω
Power Supply	2mA - 20mA（typical 4mA）
Pressure Equalization Method	Post-equalization
Connection	BNC
Temperature range, operation	-20℃ to 60℃
Temperature range, storage	Temperature：25℃±5℃，Humidity：50%±15%RH（Ensure the long-term stability of the sensor）
Humidity range non condensing	10 - 90% without condensation
Humidity coefficient	<0.1dB

Typical frequency response curve

Dimensions

Overall length	85mm
Diarmete	13.2mm
Diameter (excluding protective grille)	12.7mm
Preamplifier mating threads	11.7mm - 60UNS

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.