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Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Complex sound intensity precision meter with three- dimensional radiative and oscillatory spectral resolu- tion. Ref. CNR 10541 AAssignee(s): CNR, University of Ferrara, University of Chilecito CNR Institute: IDASC Main inventor: Domenico Stanzial Countries: IT Priority date: 22/06/2017 Abstract The invention consists of a methodology and device for measuring the 3D spectra of complex acoustic intensity starting from the estimation of the wave impedance and the auto-spectrum of the particles of the medium in the direction of the energy flow. The real part of the impedance is related to acoustic radiation and therefore to the absorption properties of the acoustic environment, while the imaginary part provides the spectrum of 3D energy oscillations due to the modal structure of sound and sources. Unlike current intensity meters, that measure intensity from the cross-spectrum of pressure and velocity, this new methodology allows to minimize experimental error in any sound field and perform a precise calibration of the pressure-velocity sensors. Background Nowadays intensity techniques are mainly limited to the measurement of the sound power (active intensity) of acoustic sources due to the difficulty of using the instrumentation. In recent years, with the availability of new MEMS sensors, it is possible to directly capture the particle velocity and therefore the intensity can again become the main technique for many other applications. In particular, this new methodology allows you to accurately measure reactive intensity. Technology The methodology is based on the direct acquisition of pressure and velocity signals through MEMS sensors compatible with CMOS technology. The device beyond the complex intensity measurement based on the calculation of the impedance, includes the calibration process of the probes used for the intensity measurements. Advantages and Applications - Minimization of experimental error and physically correct measure of complex intensity. - Calculation of fine-band spectral distribution of the radiant and oscillatory energy flows and total reactivity at the measuring point for industrial, audio-architectural and audiometric applications. Development stage Currently the invention is at the experimental stage using laboratory instrumentation and its prototyping is undergoing. Measurements have been performed in a variety of references acoustic fields to verify the correct operation 15 of the device.