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Noise source classification

Sixense Oceania

Nora™ is a machine learning algorithm that tells if a noise is generated by a work site, or not.

Nora™ is a value added technology to Sixense's noise monitoring services. When an alarm is triggered, the recorded sound wave is analysed and compared to a library of previously classified spectrograms. The outcome is the identification and classification of the noise sources with a level of reliability usually greater that 97%.

Nora™ Features

Continuous & realtime noise monitoring

Nora is applied to a continuous and real-time noise monitoring station that is installed adjacent the site to be analysed.

Continuous & realtime noise monitoring

Sound wave analysis

When an alarm is triggered, the system analyses few seconds of the sound wave that has generated an exceedance.

The resulting spectrogram - or fingerprint of the sound - is compared to large library of previously recorded and classified signatures.

Sixense currently holds more than 1,000 different reference noise signatures and counting.

Sound wave analysis

Source classification & identification

The outcome of this process is a real-time classification of the source that has generated the alarm. Is it linked to the construction site or urban environment?

Advanced classification may also identify the nature of the source; crane, jack hammer, pilling, excavator, etc... for construction sites - or sirene, helicopter, motorbike, music, etc.. for urban environments.

In addition, the sound wave is available as an audio file for playback and further investigations or verifications.

Source classification & identification

Projects using Nora™


The Barangaroo development project is completing the sweep of experiences along the Sydney CBD western waterfront and involves the construction of a number of landmark towers and structures.

A comprehensive and integrated real-time monitoring system was installed to monitor the foundation excavation and construction. Due to the heavily polluted ground material, all instruments were automated with wireless real-time dataloggers, to reduce man-power on site, and streamline data collection and reporting.


Load cells


Automatic inclinometers


Groundwater piezometer


for reporting

Barangaroo Barangaroo

Quay Street

To protect Quay Street in downtown Auckland, seismic strengthening of the 100-year-old seawall is needed to secure the area for the next 100 years. Without the Seawall, significant parts of downtown would be under water.

The Quay Street construction site has noise limits set at low levels due to many hotels operating in the area, especially when night-time works are required. The solution that has been deployed is NOVIA, a machine learning sound recognition algorithm for noise management developed by SIXENSE.


Noise monitors


Vibration monitors


Alarms processed


Classification accuracy

Quay Street Quay Street Quay Street
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