01dB DUO

Noise monitor

01dB introduces the new version of the DUO Smart Noise Monitor. Totally modular, DUO provides its users with the most complete offering to upgrade from sound-level meter to monitoring station without changing equipment.

Key points
Product features
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Key points



01dB ecosystem

The 01dB ecosystem is all about synergy between the products in its new range. ORION, FUSION, DUO, CUBE: 4 units, 4 fiels of application but one single ecosystem focused on improving your productivity. To this end, they all operate in the same way with respect to the integrated keyboard and Web interface. They use identical data processing software. And they all share the same accessories.
These complementary and innovation-packed systems offer harmonized and intuitive interfaces so as to ensure major time-savings for users.

Innovative characteristics

DUO has innovative characteristics never before achieved by any producer in a single device:

  • rubber grip for better handling
  • colour screen perfectly legible in direct sunlight
  • 3-key pad for simplified operation

Users now no longer need to choose between two systems. DUO is the right choice every time.

Regulatory metrology

DUO has obtained the following CEI-61672 Class-1 certification:

  • France: type certification No. LNE-21674 Rev 0 of 21 July 2011 issued by LNE (Laboratoire National de métrologie et d’Essais
  • Germany: type certification No. PTB-1.63-4052726 of 6 February 2012 issued by the PTB (Physikalisch-Technische Bundesanstalt)
  • Switzerland: type certification No. CH-A3-120296-00 of 31 February 2012 issued by METAS (Bundesamt für Metrologie)
  • Portugal: type certification No. of 30 July 2012 issued by Instituto Português da Qualidade, I.P.
  • Spain: type certification No. 111839001 of 9 March 2015 issued by Centro Español de Metrologia (CEM).

These certifications were obtained for both reference directions 0° and 90°.

Calibration and verification

To simplify the installation of DUO on the site, a function for the automatic detection of a calibration acoustic source allows the performance of a calibration and adjustments without the user needing to do anything more than switch the device on. Furthermore, to ensure proper operation, an integrated measurement-chain verification system performs periodic checks. Electrical verification allows the testing of the entire measurement chain, including the microphone. It consists of injecting an alternating sinusoidal load on the microphone’s terminals at the selected frequencies at one or two levels. The principle is to read reference values and check the deviation with respect to other measured values over time.


DUO natively integrates several modules for communications with external terminals:

  • Direct USB connection
  • Ethernet network (RJ45 cable)
  • Point-to-pointWi-Fi network
  • 3G communication thanks to the Modem option (SIM card and subscription not included).

With a communication device (smartphone, tablet, PC…), the user can take control of the DUO using a simple Internet browser. DUO incorporates a web server called dBDUO, which provides access to all device functions (configurations, coding, acoustic calibration and electrical verification, real-time display of instantaneous values…). Connection can be made wirelessly either in Wi-Fi mode or using the 3G modem.

Events module

DUO incorporates two very advanced event detection modules.

  • Basic module: the user can define an event, comprising a trigger that can be programmed over a maximum of 24 time periods. All settings (overall level, spectral level, rolling Leq, weather settings, etc.) instantaneously stored in the logging interval can be used to define the trigger. The event can be activated according to the days of the week and will trigger different actions: sending of a customized text message, recording of the audio signal, triggering of a parallel recording with a fine logging interval, TTL output, etc.
  • Expert module: with this option, up to five events can be programmed, each comprising a combination of logic statements (“AND” or “OR”) for several triggers (max. five).

Wireless vibration

Deploying cables reduces operational efficiency, so DUO eliminates the need! For the first time, wireless three-axis vibration measurement is available on a sound level meter. The three vibrational signals are recorded at the same time as the metrological audio recording and acoustic indicators (instantaneous and spectral). All these measurements can be processed directly using 01dB software programs such as dBTRAIT and dBFA.
Innovative, simple and above all extremely effective!

Building module

The new “Building acoustics” module of DUO has been developed to improve acousticians’ productivity when doing measurements to assess the acoustic performance of buildings. It includes many innovative features:

  • Smart organization of measurements for effective post-processing
  • Automatic detection of the type of measurement performed
  • Measurement quality indicators for reverberation time (ISO 3382 standard)

In addition, the dBInside PC-based software allows for an efficient processing of the measurements performed with the “Building acoustics” module of DUO:

  • Automatic distribution of measurements for each test
  • Ratings calculated immediately on data transfer, without user intervention
  • One-click report covering all tests

Discover 01dB Smart Building Acoustics Solution!

Acoustic indicators

DUO includes all the indicators expected by acoustic engineers: Leq, Lp, 1/1 or 1/3 octave spectrum, Fast Slow… These indicators may be measured and stored on the basis of an integration period (IP) of 20 ms (min.) to 3600 s (max.) in 5 ms steps.

In addition, 01dB also offers:

  • Perceived aircraft noise level: PNL and PNLT
  • Equivalent sliding noise level
  • Sliding statistical level
  • Noise exposure level.

The latter 3 indicators are mainly used for the monitoring of construction sites for the detection of noisy phases.

Meteorological interface

DUO offers the possibility of interfacing with the VAISALA WXT520 (6 sensors) and WMT52 (2 sensors) stations. 01dB has selected these 2 stations for their specificity of not having any moving parts. This avoids any risk of mechanical operating failures due for example to ice or wear. The meteorological station and DUO share a common power supply, and the station’s connection cable is 10 m in length, thus allowing great installation flexibility. The meteorological data are stored on the DUO and transmitted in the same way as the acoustic data (USB cable, 3G modem…). The integration period for the meteorological data is a multiple of that applied to the acoustic data.
With the remote interface, the user may visualise the meteorological data and wind direction in real time.

DMK01 external unit

The installation of a DUO sometimes requires the use of an external microphone line. To respond to this need, 01dB offers the new DMK01 unit, that comprises:

  • stainless-steel body
  • specific preamplifier allowing the re-use of the microphone and spike supplied with DUO
  • specific anti-wind ball
  • a dummy microphone to protect DUO when the microphone is removed.

The unit connects to DUO’s preamplifier input via a cable of 3 to 50 metres in length. The periodic electrical verification function remains available.


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