[Elecraft] Difference between "real" filters (FL1 thru FL4) and DSP filters (SF1 thru SF4)

[John Wiener]

I have been playing with the KDSP2 on my K2 and was wondering if the  
DSP filters are significantly different in their effects than the  
effects of filters FL1 thru FL4.
To me, they seem a bit redundant, in terms of audio effect on listening.

Noise reduction is remarkable when activated...still learning how to  
use it for SSB, however.
I haven't seen the effects of the notch filter yet...is that supposed  
to eliminate adjacent carriers?

John
AB8O