Thank you Perry Cook, for your reply. I have found what was the source of my main problem. It had nothing to do with quality, or sample size of generated file. Actually I was working on files located on an USB memory stick, and the stick was plugged in a USB hub device located very near speaker. When ChucK was executing file there were no interference between the USB cable and speaker cable, but when I was playing recorded file from the same USB there were some interference between cables that sounded like cracks. When I copied generated file to my desktop and played it from there, cracks disappeared :-) Maybe this will help somebody else if one run into similar problem.