Erich,
thank you for chiming in but unless you say which your original frequency response limits were it may be something else.
brucek,
here is a frequency response measured from 20 - 180 Hz of a full range monitor, no smoothing applied.
The waterfall shows all the peaks and dips but is compressed with to a range from 20 to 92 Hz.
When I switch the frequency axis to logarithmic then it looks better:
I think it is clearly a bug concerning the linear presentation of the waterfall.
Regards
Hannes
What can I do?
Hannes