I noticed that comment way back when he posted it, I think I worked out he was using well below 2V input (I think even below 1V), but can't remember the details. I've used them with a 2V DAC and the -10dBV setting on the back of the speaker and it's fine, albeit I've ran anything from -7dB Negative Preamp (back when I was us a Low Shelf boost EQ combined with roomEQ) to -2dB Negative Preamp when not using the Low Shelf boost and they've been fine. I suppose what you could do to test it hook up a 2V DAC (assuming that's gonna be your input), then sine sweeps at full signal (0dBFS) in REW & measure it with UMIK to see if you get any high distortion, you'd run the speakers at a low volume (on the volume knob on back of speaker) to ensure it's not distortion being created by running at a high SPL. Maybe that way you can see that the distortion is a result of the clipping, mind you thinking about it we're talking about measuring Harmonic Distortion here, so clipping distortion will not be Harmonic Distortion, so that means that test I described is not valid then. Hmm, I suppose you could still do the test I described but listen to the sine sweep to see if you get any obvious clipping. Hmm, I've not pushed speakers like this to try to identify clipping due to too high a voltage input, praps some other members can chime in with a test you could do to determine what the max voltage input can be before it clips?