The research aims to design and to develop a system of active reduction of the background noise as it is perceived by the operators of call centers, with a headset similar to the ones usually used in the team workspaces. The proposed environmental study will make it possible to grasp the global context of the functioning of the call centers. For that, this study brings together researchers of different laboratories, the one as specialist in the physical approach of the noise environment, the other as specialist in environmental psychology. Indeed, noise represents a major nuisance in many occupations. In certain cases it even can cause, in the long run, an irreversible deafness. Among all the techniques aiming at reducing the noise level in the workspaces, the active noise control is an innovating method which can prove to be effective, in particular when the low frequencies prevail. For making this method efficient, it is essential to study the acoustic comfort. The definition of acoustic comfort on the workplace, as well as its ways of implementation, require to take both, the sound reality and the perception of the noise by the users of these spaces, into account. Thus, if our subject is really the noise environment of workspaces, it is nevertheless necessary for its study, to approach it at the same time recontextualized and articulated with the different aspects of the physical and social environment of the place concerned. We prepared two standardized questionnaires, the first addressed to the operators, the second to the supervisors. The survey among the operators allows us to collect all the data relating to their opinions, representations and expectations as for their work environment. It gives us the opportunity of collecting, in an accurate way, the perceptions and evaluations of topics concerning the different parameters of this acoustic dimension as well as the adopted behaviors towards these sound characteristics. Additionally, the data provided by the supervisors concern the objective aspects of the work environment and as such, allow us to put the subjective data into perspective. It is a question of studying several call centers which are rather representative for the different existing centers. In the choice of the centers, we applied two predominant criteria: - Type of service (externalized or internalized), - Density of operators per team space (high, average, low). The so collected data processing will allow a fine and detailed analysis of the specific work environment of each center. The sample study will provide a base of information which will be useful for the work of our partners in this project, but also for the call centers themselves as it gives a global vision of their occupational work environments.