The software was created specifically for Iguatemi to solve the problem of adding sound to an already noisy environment, but can be applied to other locations with similar issues. In developing this software we combined concepts from sound engineering and programming in an innovative way to control sound pressure levels while using a playlist. We created this concept imagining a robot DJ: a system that can adapt the playlist responding to ambient noise, keeping the sound pressure levels under control. The operation is automatic and, through microphones installed around the mall, the system can calculate the variance in ambient noise generated by the flow of people in real time. More than just the volume, we can control the sound of specific instruments or vocals triggered by Ableton Live (a DJ software). We can keep or mute tracks depending on the level and range of frequency of noise detected, thus allowing the playlist to react to any abrupt changes in movement or behavior of customers. We were careful that the sound system would be projected with highest intelligibility. Using a process of auralization, we aimed at capturing the acoustic characteristics of the local, better directionality, and sound fidelity. The playlist was created based on specific moods (tedious, anxious, relaxing, and exciting), taking into consideration the customers behavioral profile and the shopping mall’s goal depending on the time and day of the week. We proposed a valence vs. arousal graph, naming each quadrant according to the context of the mall. The development of each mood started from a list of musical and sonic parameters that was adjusted for each period of the day, targeting the main public frequenting the mall at that time.

We already knew that there was equipment that could adjust music volume in retail environments in response to background noise level; however, this system only altered the volume of entire songs of the playlist. Our project was more challenging: to identify the ambient noise and, in real time, control the individual instruments in a song that could be conflicting with and adding to the frequency range of the noises from the mall at that moment. The idea of promoting an agreeable environment and sophistication through an organic playlist had not been developed before this –neither the Brazilian nor international market had seen this kind of innovation. Transcending the technological aspect, the control of noise combined with the musical playlist based on moodsand their organic interaction through our software resulted in a controlled, more agreeable, sonic environment; furthermore, this outcome also influenced the productivity of collaborators and other associated employees. Another positive aspect of the project is that the software, combined with the measures taken to reduce controllable noises, managed to reduce the background noise level of the mall from the initial 71dB to 68dB. Finally, there was an increase in the time customers stayed inside the mall, positively affecting sales.