The article focuses on the analysis of acoustic emission signals generated under dry sliding friction conditions. Two tests were conducted using a TRB 3 tribometer with the disc made of 100Cr6 steel with a DLC coating, and pin made of corundum (Al 2 O 3 ) and steel 100Cr6, respectively. Two tests with the disc without DLC coating were also carried out. The audio data written in the 16-bit linear pulse-code modulation (LPCM) format were analysed using the SpectraPLUS software. An Aweighting filter and 1/1 and 1/3-octave band filters were used for sound level measurements.The analysis of the equivalent sound level calculated for 10-second time intervals was carried out. The highest A-weighted sound level occurred during the first 2 hours of the test with the disc having a DLC coating and pin made of 100Cr6 steel. At the end of this test, the sound level dropped by about 40 dB compared to the maximum. The lowest A-weighted sound level was recorded during the last 2 hours of the test with disc having a DLC coating and pin made of corundum.The time-dependent variability of sound parameters was predicted using the regression tree and random forest models, which proved to be accurate and easy to follow.