The 1/2″ measurement microphone MP30-Infra makes it possible to use a high-quality, pre-polarized measurement microphone capsule MK 222 E on measurement systems with IEPE supply. Typical applications include low-frequency measurements.
The MP30 preamplifier is designed with a frequency response of 0.1 Hz to 200 kHz and can be fitted with a microphone capsule suitable for the application.
The MI-MKAL microphone holder is recommended for mounting the microphone. The use of 1/2″ measuring microphone capsule accessories, such as windscreens etc., is possible without any problems.
The measuring microphone can be calibrated with the sound calibrator 4010, CA 111 or with other suitable sound pressure calibrators.
Class 1 – WS2F – DIN IEC 61094-4
- Sensitivity 50 mv/Pa
- IEPE constant current supply 2-20 mA
- Directional characteristic: omnidirectional
- Frequency response: 0.5 Hz – 20 kHz (± 2 dB)
- 0.5 Hz – 3.5 Hz: ± 2 dB
- 3.5 Hz – 4 kHz: ± 0.5 dB
- 4 kHz – 20 kHz: ± 2 dB
- Acoustic noise floor 15 dB A-weighted
- Measuring range 15 dB(A) to SPL peak (5% dist.) 135 dB
In this presentation, I will show you how to measure hum and infrasound using a calibrated USB measurement microphone.
Data analysis is performed using the open-source software SCILab.
The script, user manual, and report template are provided free of charge by engineer Edwin Krasser.
The first class 1 WS2F-compliant infrasonic measurement microphone with USB interface on the market.
It is equipped with a pre-polarized 1/2” microphone capsule that has been specially developed for low-frequency applications and works in a linear range from 1 Hz to 20 kHz.
The iSV1611 USB microphone preamplifier is able to perform measurements in two different level ranges simultaneously.
The measurement of infrasound is possible with very low ambient noise from a level of 15 dBA.
The USB microphone preamplifier is designed for three different sampling rates: 48 kHz, 96 kHz and 192 kHz.
This allows the iSV1611 digital preamplifier to be combined with other microphone capsules, e.g. for ultrasound or high-level measurements.
MK 222 E Microphone Capsule | IEC 61094-4 Type WS2F |
|---|---|
Diameter | 1/2″ |
Frequency Range | 0.5 Hz ~ 20 kHz (±2 dB) |
Responce Type | Free field |
Electrode Forming Voltage | 0 V |
Sensitivity (dB re 20 μPa) | 50mV/Pa (±1.5dB) |
Capacitance at 250 Hz | 18 pF |
Maximum Sound Pressure Level | 135 dB |
Intrinsinc Noise Level | 15 dB (A) |
Operating Temperature Range | 10℃～+ 50℃ |
Operating Humidity Range | up to 70 °C, 90 % |
Temperature Characteristics |
< 0.015 dB/°C |
Humidity Characteristics | 0.001 %(RH) |
Aging Drift | 0.2 dB/Year |
Storage Temperature Range | -20 °C ～ +60 °C |
Storage Humidity Range | 25 % ～ 90 %(RH) |
Venting |
rear vented |
Outer Dimensions | Ф 13.2 mm x 10.9 mm |
Weight | 8.3 gram |
MP30 | Preamplifier |
|---|---|
Frequency Response
(re. 250 Hz) | 0.1 Hz ~ 10 Hz ± 3 dB 10 Hz ~ 20 kHz ± 0.1 dB 10 Hz ~ 200 kHz ± 0.2 dB |
Gain | 0.04 dB |
Intrinsic Noise (20Hz ~ 20kHz) | < 5 μV A-weighting |
Distortion (THD) @1kHz
1 V | < 0.1% |
Output Impedance | ＜50Ω |
Max. Output Voltage | 6.5 Volt RMS @ 21 Volt IEPE DC Offset |
IEPE Power Voltage | 18 V ~ 30 V | Bias : 12.5 Volt |
IEPE Current | 2 mA ~ 20 mA |
Polarization Voltage | 0 V |
Dimensions | Ф 12.7mm × 70 mm |
Weight | < 20 g (cable not included) |
Operating Temperature | – 20°C ~ + 60°C |
Humidity | 25 %～ 90 %(RH) |
Atmospheric Pressure | 65 kPa～108 kPa |
Connector Type | BNC |
Thread for Microphone Capsule Mounting | 11.7 mm-60 UNS |
Structure-borne sound measurement in buildings
In this presentation, I will demonstrate how infrasound and low-frequency building vibrations can be measured using a seismic accelerometer.
The measured structure-borne sound source, with a frequency of 80 Hz * 60 seconds, with 4800 rpm, is a NAS fan located in the corner of a building.
