[Elecraft] What should I be hearing when I use the K3 Noise Filter?

[Robin Diane Goldstein]

hi all...  elecraft/k3 newbie here (new owner of gently-cared-for 
#2102)...  have read everything i can find, but can't dig up an 
answer, so this is my first post to the list:

i've downloaded the latest beta firmware and have read all the posts 
reciting joy and jubilation (my words) in connection with the 
operation of the Noise Filter... but i think i'm missing something... 
i work almost exclusively SSB and find that i'm listening to stations 
buried in the QRN...  i -thought- this was where the Noise Filter was 
suppose to help, but when i turn on the NF and adjust it from 1-1 to 
4-4 i seem to hear a somewhat filtered/somewhat distorted version of 
the input signal.  i understand that the filter works automagically, 
but as i go from X-1 to X-4 it sounds like some kind of notch filter 
is being applied in increasing amounts, but not in a 
meaningful/useful way...  then it goes from X-4 to Y-1 and the 
narrowing 'hiss' starts all over again, this time with a slightly 
harmonic distortion.

on very strong signals i can sometimes find a setting (usually 3-2 or 
3-3) that sharpens up the audio just a bit, but those signals usually 
are loud enough to blast through the noise anyway... what i'm looking 
for is help with the S2-S3 stuff.

any advice or perhaps a pointer to an audio/video file showing the 
filter in (proper) operation?

btw, the NB seems to work just fine as does the notch filter.

many thanks and 73!
robin (K9RDG)