im a bit confused and would like to know how to get this working.

I'm trying to add an LFO (waveform) to a filter (second input). I noticed the filter will just noise and glitch when higher then filter.frequency(13000). (standard?)

If I add the LFO the cutoff freq will of course reach this maximum value and start to noise
How should I "cut off" the "too much"-LFO-values?