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Wireless Sound Level Meter Class 1

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Wireless SLM Class 1 by SINUS Messtechnik GmbH

Soundbook/NoisePad + SAMURAI software +wireless microphones (incl. transmitters and receivers)


The SINUS Type 1 MM255 Wireless microphone system enables single or multiple noise level measurements to be made by a single operator with the microphone located at some distance from the operator and with no intervening microphone cables.

A typical measurement example could include an operator standing on the exposed side of a noise barrier with the microphone on the shielded side. The operator can observe the action of the noise source and start or stop the measurement, as well as seeing the noise levels and spectra in real-time.

Further two channel examples could include measuring noise levels on both sides of a roadway, on either side of a noise barrier, on either side of a wall, or door, or window in an  office, internal and external measurement in a vehicle. There are also many other situations where the measurement locations are hard to reach, or where cable connections are not possible or practical, or where it is desirable for multiple simultaneous noise levels to be recorded by a single operator, .

The Soundbook/NoisePad can be transformed into a single or multi-channel wireless sound level meter  (up to 12 channels) where there are no cables connecting the microphone(s) to the Soundbook/NoisePad where the operator is located.

The MM255 wireless microphone system is supplied with a custom made Microtech Gefell preamp to work with the Line 6 wireless transmitter and a Type 1 Microtech Gefell microphone capsule. Up to twelve microphones may be connected into a single sound level measurement system.

The wireless microphone system can also be used alongside other microphones with cable connections to the SoundBook/NoisePad, to allow for a versatile range of meter configurations.

SAMURAI software is used to display and analyse all measured sound levels using the Soundbook/NoisePad.

The base SAMURAI software includes features such as:

SAMURAI software SLM – Sound Level Meter

  • Class 1 according to IEC 60561, 60804, 61672
  • Simultaneous A, C, Z frequency weightings
  • Time weightings Fast, Slow, Impulse
  • Lp, Lmax, Lmin, Leq, Lpeak of all level values
  • LE, LAtm1/3/5, Ln
  • 10 Percentiles
  • Acquisition of  impulse and low-frequency levels
  • Parallel storage of up to 5 sound level meters per channel with 61 measurement values at freely adjustable time intervals
  • Triggered storage possible

1/3 octave and octave analyzer

  • 1/3 octave filter according to IEC 61260 Class 0
  • Third-octave and octave band analysis in real time
  • Third-octave middle frequencies from 0.04 Hz … 80 kHz
  • Selectable third-octave band ranges (acoustics, vibration and user-defined)
  • Selectable averaging modes: linear, Fast, Slow, exponential
  • Simultaneous display of momentary, max, min and Leq spectra
  • Display and storage of total level
  • Display as bar, contour or line graph
  • Up to 5 third-octave and octave band analyzers per channel
  • Triggered storage possible

It is possible to display multiple spectra on one graph such as Leq, Max or Live.
A reference spectrum curve can also be plotted on the spectrum graph.

The base SAMURAI software allows for display of time signal as part of the wav recording.

A digital Level Recorder can be used to display the variation of acoustic levels and parameters over time. In addition multiple time histories of levels or spectra can be displayed in real time (such as Linear versus A-weighting levels).

Sonograms which are level versus frequency versus time can also be displayed in real-time during each measurement. Logarithmic or FFT sonograms are available for simultaneous display.

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