Eliminating spade connectors, upgrading bits, soldering all of it in

@decooney, you're a brave man posting such an incitive outrageous idea. I commend you for it.  For mass produced speakers on an assembly line a preassembled cable harness with press-on connectors speeds up the whole process, saving time and skilled labour and time as we all know is money. It most certainly is not for superior sound. They mostly consist of Brass and Tin or Nickel plating and all the metals are low down on the IACS chart.

There is also much to be gained by improving the XO in terms of orienting the inductors correctly (costs the modifier nothing except a little time) and replacing the ubiquitous white sand cast resistors most of which have magnetic ends.

Now before the swarm of deniers pile on the above statement I challenge you to a simple experiment: To those who are skeptic and have access to the XO inside their speakers but taking care not to void their warranty, try this:  In almost every case there will be at least one and usually two resistors forming an L-Pad to attenuate the signal to the tweeter, yes? Yes. Find the series resistor, look for that noisy white thing, often with a value between 2 and 6.8 ohms. Lets go with 6R8. Unsolder it and replace it with a string of 10 x 0.68ohms all soldered in series = 6R8 and listen to the difference and you will hear the damage components make.

Expectation bias be damned!  Consider too the big bold speaker binding posts even the $$$ speaker brands use.  Brass is used because Cu. does not machine as easily and strips under torque and then plated with Nickel because it polishes beautifully and then finally Gold plated resulting in a georgeous piece of audiophile porn. You now have a chunk of 3 dissimilr metals in your precious signal path.

Good speaker terminals are scarce but available. 

As @waytoomuchstuff ​​​​and @gdaddy1 in essence stated: It all adds up.

Shocking!  No one with really good equipment would do this.  Value just went to ZERO!!

@gournard In almost every case there will be at least one and usually two resistors forming an L-Pad to attenuate the signal to the tweeter, yes? Yes. Find the series resistor, look for that noisy white thing, often with a value between 2 and 6.8 ohms. Lets go with 6R8. Unsolder it and replace it with a string of 10 x 0.68ohms all soldered in series = 6R8 and listen to the difference and you will hear the damage components make.

Yep, 100%, exactly the point.  Over four decades, on the 43rd and 44th set of speakers I built, with some help from a few friends with access to an isobaric chamber, who helped me on the design of more capable crossovers - -  Once the best L-pad settings were determined, the prior L-pads in the circuit were completely removed and replaced with the right resistors and filters in the next pair of speakers.  Never looked back since. 

The next step was to compare an original set A with L-pads and the updated set B without L-pads.  The difference was quite notable. More open, detail, and more realism to instrumentation.  I often times use piano keys to judge difference in A/B test cases.   I A/B’d these two sets back and forth over two weeks, and there was no reason to continue with any L-pads in the speakers at all. Get ’em outta there. 

"Damage removed", out of the signal path, making a rewarding difference here too. One of the other benefits of building your own, DIY, revise the design how you see fit to your taste.  

Other-Beta Test:

During this same time I completed an evaluation for a known manufacturer, with  a 3rd set, completely stock with zero mods, new from the factory. These were intermixed with the two other pairs with minor to major mods, upgrades.  It did not take long for the 3rd set to get boxed up and sent back after their normal break-in time had passed.  No reason to keep them around, they placed #3 out of 3 pairs.   

When I changed my speaker wires from relatively inexpensive Synergistic Research wires to Silversmith Fidelium cables, the change was pretty dramatic. I talked to Jeffrey Smith about it and he suggested trying some heavy banana to spade adapters.  He explained what this did.  It made the Fidelium sound more like my old wires, but still better.  I ultimately got rid of the adapters, but I found the whole concept quite interesting. 

@kymanor1 

"Shocking!  No one with really good equipment would do this.  Value just went to ZERO!!"

Dang, it’s hard to argue against logical points. But, as the elderly gentleman said after a desperate attempt to find a restroom ... "Depends."

Being a "car guy", I’d like to draw some parallels, if I may.  There’s "showroom stock" with everything intact that was there the day the car was built.  "Personalized" where the owner enhances the vehicle in some way.  Usually performance options, but often includes comfort, handling ... AND ... safety upgrades.  Then, finally, there’s "modified" where all the "rules" are off the table and you take a cutting torch or hammer to existing metal if they get in the way of ultimate objectives.  The most popular group is "personalized" for many reasons.  Mainly, someone loves the car, but wants to go faster/quicker, stop shorter, and stay flat in the curves while those fat(er) tires grip the road.  A little "ginger bread" added -- cool wheels, custom paint, etc. makes the vehicle uniquely "yours." A KEY factor at this level is the ability to return to "showroom stock" at some point of decide to do so, provided they didn’t give away that old 2bbl intake manifold, etc.

Personally, I’m in the "personalized" category.  Yes, I like to hear "good noises" when I get on it.  But, primarily, I don’t want to find my self on a wet street with 4-wheel drum brakes and skinny bias ply tires.  My "hill to die on" is NOT the preservation of a particular marque, but the preservation of myself, and those I care about when enjoying MY hobby -- in traffic.

While "showroom stock" represents the high mark for market value, I’ve also found that professionally built, and well-documented, "personalized" vehicles come very close to those pure, unmolested, versions.  I also believe this depends on the price class of the product. For example, the ’Holy Grail" vehicles -- those valued at, say, $250k and above would appeal exclusively to purists and/or investors.  Those valued at less than that may have some devaluation, say 20%, for professional builds.  The 20% penalty may be money well spent for those who actually DRIVE the cars and thrash them on occasion.  Or, want to pack up their significant others to provide the safest, most comfortable transport from Point "A" to Point "B." 

An insurance salesmen once told me: :If you can afford to take the hit, don’t buy insurance."  Adhering to this line of reasoning, related to "personalization" : "If you can afford to take the hit, enjoy the ride and don’t worry about the depreciation."

So, yes, this is an audio forum, so it’s time to take it back to music/equipment.

The goal of the "modder" is not to paint a mustache on the Mona Lisa, but to deliver the performance the original designer intended IF freed up from the burden of operating efficiencies, infield service considerations, time constraints, and material costs. We operate under "Signature Systems" badge in our little, part-time service/performance mod business.  When we are finished with a project, the tech signs off on a document attesting to the fact that he followed the process exactly as prescribed.  I would like to believe that our professional "mods" would have minimal impact on "market value."  But, this is hard to say because our customers will need plastic surgery to get the smiles off their faces when we deliver the finished project.  They have NO intention of selling them -- ever!  And, by the way, our "personalized" mods can be reverted to "showroom stock" in many cases.

So, to wrap this up:

Spend the next decade taking your enjoyment of music (with your current gear) to levels that you had never imagined?  Or, not have your portfolio dinged up and bit because you had the audacity to yank stuff out of the box that made it sound worse?

To "borrow" the quote from the insurance guy: "If you can afford to take the hit from the mods, DO THEM!!" If not, then wipe off your equipment with a soft cotton diaper daily to protect your investment.  Is your "hill to die on" the protection of the marque (and, your investment)? Or is that "hill to die on" to provide the most engaging musical experience you can have in your home -- without reservation, or compromise?