The control of surrounding sound is only one part to make decent acoustics and privacy of speech that is a very actual issue in newly built, modern, open type office buildings where one of the largest workers’ dissatisfaction is created exactly due to the surrounding sounds. Obstructive sounds are speech, printer, typing, call of telephone that asks for control, because such sounds diminish the concentration of the employee’s that gives a negative effect on employee’s working efficiency. The source of the sound can be isolated or decreased, travelling sounds can be absorbed and blocked with good office layout and used materials so that the sound is not travelling from one working place to another. The best way of sound control is by office design. So that is would be easier to make a working space with higher level of privacy there is created small, free of charge computer program where one can model the height of the walls, material used, work space layout and analyze the results. In open plan offices, it is possible to improve the speech privacy by using different quantitative measurements and watching the results of them. If we better understand the importance of very effective acoustical environment, we see that an environment contributory to speech privacy, concentration and productivity can only be made through the balanced use of the methods of noise control that were described in the article: reducing noise at the source, blocking noise travelling, absorbing noise, and masking the noise. Author has looked also at speech privacy measurement correlation, and also there are showed these measurements according to open type office geometrical and acoustical qualities.