Can't get some FX to work in DimPro: some SFZs

In Dim Pro 1.5 64 bit I have a Cellos SFZ loaded. "Cellos Legato Down f" was the source, but I have modified it to make it mono and not stereo. I have saved as. The original SFZ works fine.
 
- The Filter (top RHS) for each element makes no difference to the tone, no matter what type or setting I use.
- The Modulators likewise have no effect on tone. (Cut). They do work on all other aspects: Amp, Pan and Pitch.
 
Is there something in Dim Pro that needs to be fed by something in the SoundFont, that may have been stripped when I made the mono version? I used Polyphone. I will ask there as well, but the author may not know Dim Pro inside out
 
- Additionally, if I ask to get overall FX, I ask for Reverb and no matter what sized room I ask for or what settings on any of the mixers and controls in that area, no difference. Same for Modulation FX. This is regardless of the SFZ I use.
 
Any advice greatly appreciated.