**Acknowledgements**

*Acoustics of Materials*

due to the measurement grid chosen.

*(160–1600 Hz) with 10 dB dynamic range.*

**3. Conclusions**

**Figure 6.**

phone arrays.

measurement.

partition element.

If both measurements are compared, the results show a similar behavior, but intensity measurements do not identify the leakage at the bottom part of the door

*Results obtained for the anti-panic door. (a) Sound intensity map (200–5 kHz), (b) pressure map with beamforming (1–5 kHz) with 10 dB dynamic range, and (c) pressure map with SONAH in the door center* 

The sound pressure technique based on ISO 16283-1 regulation only requires an analyzer with a third-of-an-octave accuracy, both in sound pressure level and reverberation time readings. In order to apply the measurement technique based on ISO 15186-2, however, it is necessary to use an intensity probe kit in conjunction with a two-channel analyzer with higher sensitivity than that required for sound pressure measurements. Beamforming and SONAH techniques require complex and costly sound instrumentation if compared with that commonly used for in situ assessment of airborne sound insulation, whether by pressure or intensity techniques; this is due to the large number of channels required, the application of processing algorithms with high computational cost and to the design, and preparation of specific micro-

Although beamforming and SONAH techniques are usually successfully applied in free-field conditions, the use of these techniques under different conditions pinpoints those areas with higher sound transmission. The joint use of beamforming and SONAH techniques on the construction elements under study quickly allows to identify areas of maximum sound transmission on the constructive element under test. In addition, whereas the setting up and the verification of the measurement system based on beamforming and SONAH are initially a time-consuming task, subsequent measurements are carried out in less time than that needed for pressure and intensity techniques, resulting in a greater repeatability of the test and therefore with less influence of potential sound field variations during the in situ

In beamforming technique applications, the best results are obtained without reference signals, while in SONAH technique are obtained using the reference from accelerometer signals or from the central microphone of the array. The use of alternative processing algorithms in beamforming would allow greater detail and definition on the identification of different sound transmission areas through the

In conclusion, the implementation of a measurement system based on the combined use of beamforming and SONAH techniques identifies in an accurate way

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This methodology was developed and granted by the project "Determination of the acoustic insulation of solid, acoustic and fire-resistant doors" (JCCM, Ref. PPII10-0172-426).

The publication of this chapter was funded by Escuela Politécnica de Cuenca - UCLM.
