I've only just seen this thread. That's my video. I made it for the HPF thread on here. I think all the info, along with frequency curves, was in the post I made.
It was definitely using a Zoom B3 and was probably comparing single and stacked multiple AcBsPre patches.
EDIT:so I've found the post:
"With one AC BS Pre on the B3. The synth is running a sine wave 2 octaves below, so it's a bit extreme (near the end of the clip I turn the depth knob up and down to see the difference):"
With a following post saying:
"I've also just had a look at what multiple instances of the AC BS Pre might do. The frequency plot it unchanged having 1, 2 or 3 instances running."
Here's the plot from earlier in the same thread:
Top line is off, then Depth 10 - 0 (gain 50, bass toTreble 0) . Looks like once you get down to 15Hz and lower the white noise is a little less stable.