# Open-Plan Offices: Comparison of Methods for Measuring Psychoacoustic Intelligibility Parameters
## 4 Discussion  
In this case study, several elements that make up the soundscape of an open-plan office were examined. The evaluation focused on the main and simple effects, the interactions related to the different types of sound, the location of both sound sources, and the points where acoustic measurements were taken. [PERSON] et al. [24] indicated that realistic scenarios with different acoustic parameters should be explored. [PERSON] et al. [8] specified that the acoustic analysis of the soundscape should be approached with psychoacoustic parameters. Therefore, psychoacoustic parameters of intelligibility were analyzed in this case study. Specifically, the acoustic characteristics of reverberation and speech transmission were studied. The reverberation analysis indicated that the interior design influences the acoustics of the space. In this case, the construction materials and furniture generate a diffraction effect [30]. The diffraction effect is related to interior design features and their influence on space acoustics. We detected it at measurement points with significant changes in _EDT_ near areas with interior design features. For example, _EDT_ presented medium effect changes at measurement points near glass walls during this study. On the contrary, measurement points near open areas where the study concluded showed a large effect with respect to the correlation coefficients \(\beta\), this indicates that the acoustic qualities of the enclosure influenced the analyzed behaviors. This type of behavior can be considered in architectural acoustic design with virtual tools to anticipate such design effects. [PERSON] and [PERSON] [31] followed experimental techniques to simulate _RT_-based room acoustics. Furthermore, according to data presented by [PERSON] and [PERSON] [32], guidelines and recommendations should be made for the architectural acoustic design of open-plan offices. For countries that do not have an intelligibility standard, these studies can support the effects of architectural acoustic design on performance. This was demonstrated by [PERSON] and [PERSON] [33], who focused on school classrooms only using _RT_ as an indicator to assess reverberation. Their study provides an acoustic performance standard for classrooms. With this study, we can extend to study and consultation areas in educational centers. Architectural acoustic design influences the improvement of the acoustic conditions of spaces for the perception of comfort and well-being of users. For example, the critical distance, which is based on the ratio between RT and SPL to determine the distracting radius, this distance is the one that influences the perception of lack of privacy of open office users. [PERSON] and [PERSON] [34] propose a classification scheme for critical distance estimation based on speech attenuation performance. This facilitates the interpretation of acoustic measurements to determine comfort distance based on ISO 3382-3 [35]. This may contribute to what [PERSON] et al. [24] suggest about the influence of changes in the reverberation times of a room on the impact of intelligibility on writing activities. Regarding speech transmission, _STI_ is one of the main parameters used to evaluate the acoustic characteristics of the room. In the case of open-plan offices, _STI_ is used to evaluate the intelligibility levels that allow hearing speech clearly. However, it is known that this clarity of speech in background conversations can cause discomfort to users in open-plan offices [36]. In addition, following the architectural design requirements, another psychoacoustic parameter for speech transmission analysis is _%ALCons_. It is part of the subjective analysis to assess how people perceive the quality of intelligibility at different points in the room space [16]. During this study, the results indicated that sound type influences psychoacoustic parameters and measurement point assignment, although the effects were small.