I don't disagree based on your snapshots, but it sounds like a harsh generalisation. Especially when I see an image comparable to your right column on my setup.Notch filter on right side clearly is better.
As you said yourself, on the signal's way to the display (or panel) it has to run through a luma/chroma seperation process at some point. And the discussion on how and where this is done best, isn't exactly new. Enough people tried to find their optimal setups for ages.
It's also pretty common knowledge that not all CFs work well with LD content. Hell, even Pioneer totally messed up some of the CFs in their players. And this doesn't neccessarily only apply to low-end machines. The X9's CF for example is completely unusable.
My results using a Pioneer DVR as a CF are really good. And the player quality isn't this important. I currently have a S9 and a X9, but I had cheaper players before and they all looked fantastic when run through the Pio DVR.
Which Extron do you have in mind? The Faroudja isn't great. The CII is good, but it binds you to the processors video processing (deinterlacing, scaling) after all.Generally the best comb filters are probably 2D Faroudja, Extron, Crystallio, etc.
But with laserdisc it's going to require a different C.F. besides the standard type.
I think unless you can point to an available end user product which performs a better job than the CII's or the Pio DVR's CFs, then it's a bold statement to say "Stay away fromb comb filters with laserdisc!" Maybe we can agree on a "beware of using the wrong CFs with laserdisc" instead?Thought I saw some D.I.Y. schematics for cvbs notch filters.