I hate to ask. I usually try to gather what bits I understand into a cohesive whole. But some times the ‘bits’ are so scattered I feel I need to. I want to plot my FR for the sub in room. I note the cheap/bare minimum method. I found this informative BFD SETUP for my starting point. Downloaded MP3 sine waves (the 1/6 octave chart) from the link at snapbug. Question: MP3 is compressed format, does this still equate to a recording of ‘pure sine tones” since I seem to read vague hints about danger when playing sine tones for any extended length through the speakers which can damage them? Since I never download audio, Is a basic click and burn adequate? Or do levels? in my PC need to be adjusted for the download? What would be the safety rule of thumb while playing sine tones?