It´s me ..no doubts 😂 I´m not a clone or a KI 🤣      

I too used the Trade Secret for repair touch ups on other woods and it worked fine for certain types of defects.   With all due respect, the tree-hugging propaganda surrounding the VOC crusades that started in the 80's was unscientific and unsubstantiated to this day. The $ trillions in economic impact eliminating so called ozone killing chemicals hasn't resulted in any loss or gain in the ozone that can be distinguished from random chance. You'll never see that reported anywhere ... nor do you hear any more fear mongering about the ozone destruction and the end of humanity. The industry has found another more profitable boogey man.   Sorry for the rant

Thats a nice summary, thanks for posting. The literature I got with my Klipschorns was non-specific, just a fine furniture oil that does not include waxes. I tried a few from furniture stores, they were ok, but the Watco is superior.   The yellow lemon oil product tends to attract mice, until they met my cats

If these are still unfinished plywood as they came from the factory, then it depends on what you intend to do.  If you want to keep them in "raw" (unfinished) condition, then just dust them.  Putting anything on them will cause it to soak into the wood.  However, applying a finish of some kind will protect the wood, especially from getting stains.  You can apply almost any finish with or without staining them first - lacquer, polyurethane, varnish, etc.  I presume you could even apply furniture oil to the plywood to create an oiled finish, although I don't know how even the absorption of the oil would be on the edges since there is glue between the layers of the plywood.  However, most people who purchased speakers with raw plywood usually applied a sealed finish like poly, lacquer, etc.

As far as I know, these multiplex woods are also finished with a veneer. For example, next week I am buying a 1973 Khorn made of birch plywood covered with fir veneer. But just “raw”. So no oils in this case?

I'm a big fan of Trade Secret products.  Their Scratch Remover did an amazing job restoring the finish of my lacquered modified Belle Klipsch center speaker.  The furniture polish also saved me from returning my Heritage Jubilee.  There were a few spots on the veneer where when the light hit at a certain angle you could see light marks where the plastic bag of the packaging had touched the veneer.  I suspect the lacquer wasn't quite finished curing before they were packaged.  Applying the Trade Secret furniture polish made those disappear.   However, I don't think this, or most other furniture polishes, would be appropriate for oiled wood finishes.  Even the product description implies that it is for sealed finishes ("From French finish antiques to modern lacquered and synthetic coated furniture...").  You are only supposed to use furniture oil products on oiled wood if you want to retain the original appearance.  

A Lot of memories in this, just a good listen!  

I wanted to add something. The thing about art is that we have museums to indoctrinate young students into that they might know the world is larger. There is no such indoctrination or ways of gaining that exposure to see or to say what Sound is. How do you do that?    Remember that most people have not heard their voices amplified and played through a speaker or recorded even. I would say that there are people in this world that have been brutalized and given so much weight that the idea of surrender is truly possible, but it would have to be something worthy of that. Music has always, always risen to that occasion. To be present in those moments at the antipathy of everything which would develop around the nucleus of pain and uncertainty and development of who we ultimately become. This is centered around the idea of something that existed before we had the knowledge of true self. Period of doubt perhaps. A time of significant loss. Any event that was not ours to control.    The other thing to is that there is not a lot of wattage required for the systems to reproduce sound? That makes it more ideal than you could possibly imagine. For local city state Township or borough, for any municipality to be required to speak before the public to address the public at large if they wish to have those systems with the fur on it for outside venues and carry that to do all of those things. What I meant by lazy was that we have so many pieces of equipment that help us to move items. to reduce the amount of work necessary to do so. People would much rather carry eight of these different speakers than just two of what may be a heritage series. That may be of less weight.   But if it’s a fixed system. Then there is no argument. If I had a dealer license, I wouldn’t want for the state that I’m in. I would want to be able to call in airstrikes and send a team to assemble a product in a location for very specific client that serves a very specific purpose. 

There is no service manual. Just schematics and a poorly written Cal adj. procedure. Some written by hand some on a typewriter. This was back in the day before most word processors and PCs.

@coyote19702000 put a @ in front of someone's avatar name and you have a much better chance of getting their attention. How did you try to reach me? There is no real service manual. Just some schematics and a half azzed poorly written cal procedure...you know written by hand before computers existed.