The results of the design, implementation and evaluation of a semi-anechoic chamber to guarantee reliability in data acquisition for diagnosis of mechanical systems are presented. Noise analysis is one of the predictive maintenance techniques that detect faults based on the monitoring of characteristic parameters of proper functioning of a system. To do this, the characteristics of insulating and absorbent material were determined, and their arrangement inside the chamber. The evaluation was performed using the analysis of acoustic signals emitted by a source (internal combustion Diesel engine) under its normal and failure operation. These signals were acquired using a sound level meter and analyzed in the frequency domain using fast Fourier transform.