Hi @MicroMara, thanks for your reply and schematic. It is more complex than I expected. 

No complaints here.  Except for the weather.  Is it Spring yet?

I merged this thread with the one you started in Jan. of last year on the same subject so you, and everyone can follow along with the chronology.    I don't think you are going to find many folks here, or in other audio forums, that are going to have modifications for brand new Cornwall IVs that actually own CW IVs and have actually done the modifications.    There are dozens of posts by people about modifications on CW IVs, but they are ALL ads for selling you or someone else's wares.    By the way, in audio, like a lot of things, asking someone if they have tried a change and found a benefit rarely provides you with any useful information unless it is accompanied by measurements or an objective comparison. "Objective comparison" means a well set up blind test.    Floyd Toole has written extensively on this, sighted comparisons of speakers on preference are absolutely useless. Doesn't matter what the experience level or background of the listener is. This area is called "Psychoacoustics" if you want to dig deeper into it. Our brains will tell us something is different whether it is or it isn't.   This was echoed by the Father of Acoustics, Leo Beranek: Beranek's Law It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion. L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208   The only way to know for sure is a blind test. On the changes you are talking about, 100% of the people can't pick out a difference better than chance (guessing), and if there are one or two who can identify a difference, their preference is across the board, no correlation to the "improvement"   You can purchase modifications that will cause enough of a change that almost 100% can tell a difference. Whether it's an improvement requires a well-set-up blind test (volume matching, etc.) to see if the preference is the original or the modification. Why? Because people who spend money on something that changes the sound of their speakers will ALWAYS say it sounds better.    It's why PWK insisted on measurements, why he figured out a way to accurately measure distortion in speakers, identified the different types of distortion, why he built an anechoic chamber in his lab, why he published his curves with his speakers, etc.     If you want to sort out the Bullshit from the people who are trying to sell you the latest, greatest modifications, upgrades, etc. ask for the curves/measurements on the before/after. If they say, oh well . . . you know what, never mind.    This is what you do. Go out and buy some $100 per foot, heavy gauge wire, and rewire one of your speakers, have a friend/family member set them up so you don't know which is which, and then listen to them, left, right, etc. Pick which one sounds better. Repeat that 3x or 3 weeks (each fime a friend or family member changes up the speakers). You are truly blind and give it a fair shot. (You may need to determine if there is a room preference for left and right, but that's a different story for another time).   The other thing you can do is get an active crossover for one side, and 6 channels of amplification, and see about the differences you can make with that and what your preference are on slope, crossover points, and EQ. You can tinker to your heart's content and never mess up the original design.     

I've never measured frequency before, I'd hate to do any damage if it's even possible hooking up my very basic voltmeter to the terminals, I was just wondering if it may have been my Denon X8500H AVR as the pre-amp signal could've suddenly become noisier on the Left & Right pre-outs, I know most unlikely but anything is possible, I'll see how I go diagnosing the issue with the tests you noted above, thanks so much for your advice, it's greatly appreciated.

Nah way too early to say that.

Was in Austin for the GP 2 years ago. I want to go back.

I believe the bear is being told what to do. Kvetching does nothing. But you do you. I see what that's brought about.

Unrelated side note:  Appears 2025 MotoGP season already over.

As John Mellencamp once said in song, "Baby, you ain't missing a thing", so sit back and enjoy that Luxman/Cornwall system.

I have had this one for a while (~30 years). I'd like to know which edition it's from.