Sound intensity measurement – A revolution in acoustic measurement technology

The development of sound intensity measurement systems in the early 1980s had a significant influence on noise measurement technology.

In the mid 1990s the first international standards for sound intensity measurements and for instruments for such measurements were defined.

Sound intensity measurement systems enable e.g.  the determination of the sound power of sources without the use of expensive special equipment such as anechoic and reverberant rooms.

This opened up completely new, extremely cost-saving applications in acoustic measurement technology.

Today, sound intensity measurements are routinely used in industry and research to determine the sound power of machines, aggregates, equipment and other noise sources in production, quality assurance, research and development directly on site.

Other important applications of sound intensity measurement respectively sound intensity probes are, e.g., the identification and ranking of partial sound sources, the determination of the radiated power of vibrating surfaces or the visualization of sound fields as well as the determination of the transmission losses of partitions

High-End Sound intensity probes from Microtech Gefell

Since the introduction of computerised measurement systems the sound intensity measurement process, for example for sound field mapping or sound power measurement, has become very significant.

Microtech Gefell offers a wide range of selected precision microphone pairs in this area that are integrated in different mechanical constructions, e.g., for the Sound intensity probes SIS 90, SIS 92, SIS 93, SIS 190, SIS 190 double, SIS 192, SIS 193, or  SIS 194 3D for ½“ or ¼“ capsules.

Following customer requests, the different mechanical structures are originated individuell in order to optimise the use of the intensity probes.

With 1/2” and 1/4” microphone capsule pairs, a large frequency range is covered.

Using the remote control, the user is able to work in stand-alone operation and control the measurement from the measurement location.

Special sound intensity probes allows a simultaneous sound intensity measurement at one point of a room in all three dimensions, e.g the intensity probe SIS 194 3D.

The SIS 194 3D can be mounted on a robot for automatic scanning system.

The use of ¼“ constant current powered preamplifers and ½“ or ¼“ capsule pairs make measurements from 35 Hz to 10 kHz are possible.

In addition to measurement of sound pressure, each individual sound intensity probe -by its two-microphone-technology – enables the acquisition of the sound pressure gradient and thus the sound intensity computation.

The probe consists of two in phase- and frequency response matched measurement-microphone capsules.

The quality of conformity of both measurement capsules, relating to their transfer function, is measured in accordance with DIN EN 61043 and IEC 1043 respectively and documented as pressure-intensity-distance/residual-intensity-distance for probes.