DSP Robotics Support

I have been trying out some filters , found some ok ones , mostly a distorted 3 pole.
What I found with most lowpass filter , even the 4 pole 24db ones is that they do not really close down enough.
Always some low end leaking through . Is this some quirk of FS filters or am I just trying out some bad examples?

Any filter wisdom you want to share ?

Hm, lowpass filters are designed to pass low frequencies, so what do you mean by "low end leaking through"? Which filters ahve you tried in which setup? There is no limitation in FS that would prevent filters from having a good stopband rejection.

Like this one , where I cannot get the cutoff point low enough , probably something I am missing.

Oh...nevermind ,found what I was doing wrong, had to be.