The interpretation of silencer manufacturers  are usually used databases with measurement results to standards, where appropriate, with interpolation. Some manufacturers provide their customers with silencer free of such programs on a floppy disk available. Such programs are not applicable when the operating parameters are outside the measurement conditions, and they require extensive series of measurements, even if only a single parameter to be varied. The situation is similar when using the so-called trapezoidal diagrams of relevant handbooks. These represent the stylized results of analytical calculation methods dar. The calculation method itself but are now prepared for the PC. It compares calculations and measurements. Deviations from the empirical corrections to the propagation attenuation and return loss can be determined. From the computational method, a user program calculation of silencer manufacturing, developed on PC, which was used as part of a larger collaborative project.