You are correct, those are analog headphones plugged in to the headphone jack. I tried couple of them, but with the same results; and they seem to be working fine under windows on the same laptop. Also, I tried to tune up the mixer output from the pc-mixer UI before and that didn’t help, unfortunately. I’ll give it a try with the terminal when I get back home just in case. However, I’m afraid I should’ve described the “distortion” more. It sounds like if some frequencies are cut out from the output spectrum. For example, there is no speech in the output, but volume of other frequencies is high. I’d blame an equalizer if I had one set up, but I don’t. The system is on default settings. Besides, the equalizer would’ve affected the speakers output too I guess.