As vital ecosystems across the globe enter unchartered pressure from climate change industrial land use, understanding the processes driving ecosystem viability has never been more critical. Nuanced ecosystem understanding comes from well-collected and representative field data. Advances in hardware and analytical methods have revolutionised ecological monitoring and made it possible to easily uncover a wealth of information that hasn’t before been possible.

Sound ecology (bioacoustics and ecoacoustics) describes the school of research that uses information transmitted through waves of pressure (sound) to infer properties about an# area's species, biodiversity, and health.

Spatial acoustics takes this one step further By recording a soundwave from multiple microphones simultaneously, we can use millisecond time differences to triangulate where a sound has come from.

These delays can also be manipulated to amplify signals from a given direction through a beamforming.

Publications

MAARU and its applications are described in the following peer-reviewed, open-access papers.

Spatial ecosystem monitoring with a Multichannel Acoustic Autonomous Recording Unit (MAARU)

Heath, B. E., Suzuki, R., Le Penru, N. P., Skinner, J., Orme, C. D. L., Ewers, R. M., Sethi, S. S., & Picinali, L. (2024). Methods in Ecology and Evolution, 15, 1568–1579.

This paper introduces MAARU: a low-cost, open-source, six-channel recorder built entirely from off-the-shelf components that can be integrated into a solar-powered, networked system. It sets out the hardware and software and reports lab and field tests from the UK and Brazil, showing that MAARU can localise pure tones and bird calls to within ±10°, and that beamforming can improve BirdNET species-identification confidence.

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Towards using virtual acoustics for evaluating spatial ecoacoustic monitoring technologies

Le Penru, N. P., Heath, B. E., Dunning, J., Picinali, L., Ewers, R. M., & Sethi, S. S. (2025). Methods in Ecology and Evolution, 16, 108–125.

This paper develops an ambisonic virtual sound environment — a loudspeaker array that recreates real natural soundscapes in the lab — as a controlled, repeatable way to test spatial monitoring technologies. It uses MAARU to explore how device orientation affects a suite of ecoacoustic metrics, including the BirdNET and HARKBird software tools, and offers guidelines for building and using such test platforms.

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