Hi again
I was plumbing the depths with my IB today using REW's "Frequency follows cursor".
I reached 90dB @ 10Hz @ 9 feet and there was a background sound of galloping horses from my IB. A deep hollow sound like somebody beating a cardboard box in short cycles with a space in between. :holycow:
With less than 1/4" of cone movement at the time this suggests to me that the "cowboy" artifacts came from within REW. Or perhaps the electronics chain? Rather than caused by a mechanical problem. Had the drivers been hitting the endstops I think I would have heard a continuous rattle.
REW's input barograph from the SPL meter was going up and down like the water in a U-tube!
At 15Hz the galloping horses had slowed to a canter.
Any thoughts?
Thanks