In this presentation, I will first show you how we test and evaluate a suitable USB measurement microphone for infrasound measurements using an iPhone.
The MEMS microphones built into all smartphones are optimized for speech intelligibility at frequencies of 80 Hz and above.
Low-frequency sound pressure levels—such as those caused by wind gusts—would impair microphone performance and degrade speech intelligibility.
Consequently, most microphone preamplifiers feature a high-pass filter set at 20 Hz.
This also applies to all USB audio interfaces with 48-volt phantom power.
Specialized measurement devices for industrial acoustics are capable of capturing infrasound starting at 1 Hz—or, when used with the RogaDAQ 384, even as low as 0.3 Hz.
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 is a fan, with 4800 rpm, of a NAS located in the corner of a building.
Sonibel Instruments Explanatory Demo with CPO
Sonibel catches weld defects during welding, giving welders the option to rework them on the spot and minimize repair costs.
- Fewer Inspection Bottlenecks Pass inspections the first time and keep projects moving forward.
- Reduced Rework Time Address defects immediately rather than waiting for NDT.
- Less Downstream Delays Minimize the cascading effects of failed inspections on your project timeline.
The 24-bit analog-to-digital converter features a sampling rate of up to 2 MHz and anti-aliasing filters.
The LTTsmart DAQ is equipped with various inputs, which are switchable in the standard version. These include IEPE sensor inputs, charge inputs, strain gauge inputs, and counter inputs. The counter inputs are designed for high-precision rotor analysis.
The 2-channel LTTsmart measurement data acquisition system is supplied with the NVH Analysis Pro software.