Test this ...choose one osc ( simple sine wave )
Add an fm osc ....now modulate the fm amount of the fm oscillator with a square wave lfo ....it's better if you use the user hape and draw it yourself modulate it directly from the fm osc .
You'll notice that the negative values of the square wave also affect the fm amount ....
Now when you do this from the modulation matrix ( destination fm amount ), same lfo source , the behaviour is totally different ...negative square wave values do not affect the fm amount ...Also a saw wave has different results when used in both ways described ...
cheers ....after years hanging around here I finally registered on this forum
Urs