Land-mobile radio stuff. Analog, voice communication.
Our sales guy had sold a remote node for a voter system to improve receive coverage for a central dispatch system. (Signal-to-noise voters are pretty neat: They can continuously compare two or more related audio signals and [ideally!] pick the one that is best for use while discarding the others.)
That node wasn't all that far away as the crow flies, but it was a very long way out in telephone cabling miles. It spread across two different telco LATAs.
So we rented this very long series of bits of wire held together by scotchloks and punch blocks and whatever else in telephone world to use, and we used it. It was not a conditioned circuit: Just wire.
The specific endpoints of that wire were kind of neat, too: There was some basic EQ that could be used to help compensate, and (IIRC) some impedance adjustment to dial in the circuit itself.
And there was a continuous pilot tone used to set gain: Apparently, when wire gets really long like that, atmospheric conditions can dynamically change its attenuation.
Putting a pilot tone near the middle of the voice range (to be notched it out later) and using its level to set gain helps to improve consistency.
That wireline stuff all worked pretty well.
(The remote node was ultimately a bust. The sales guy also tried to cram too much shit into one feedline and antenna, and the gear to combine and separate all of those signals ate too much energy to make any of it an improvement over doing nothing at all.
Which is... well, that's exactly what the engineering told him would happen, but he did it anyway.
No part of this was inexpensive.)
You need source, digital to analog conversion, pre-amp, amp, speakers to have low distortion too, and you need the room to be appropriately treated too. I didn’t look at whether they did all that but I seriously doubt they did.
Outside of the hyper-crazies, no one is really stating that a 6-12 inches of conductor is going to make a giant difference in audio quality. Yes, I'm aware of the super-premium-gold-plated-platinum-encrusted 12" audio patch cords available. But almost no one really makes serious arguments those do anything.
I don't think running a 50ft banana is going to have similar performance to a 50ft properly-sized copper conductor though.
Where you get into the "debate" is the difference between buying a spool of 12ga stranded copper wiring from Home Depot, or buying the same thing only with de-oxygenated or whatever silliness some audiophile brand is selling for 10x the cost.
There are levels to things. I imagine copper speaker wire to be essentially fungible. Just size it to your length of run and max power needs. Calculate the total resistance for your wire run and done/done. All professional level sound installations for venues and what-have-you do this already.
This sort of test just seems to prove nothing in either direction other than provide bait for folks to point and laugh (or defend) in comment sections. Consider me baited, I suppose!
I feel the same way about wine. At a certain point, it's not really about objective improvements, it's about vibes and lore.
That said, think there is value in putting out facts that let people make informed decisions and not spend tons of money on things that don't actually work.
(And yet: They still make inexpensive cables in factories every day.)
In other words, they got fooled.
What’s happened in electronics is that there’s a cutoff, above which the audio quality doesn’t get any better, but that cutoff is much lower than anybody can believe. So the psychological cutoff is higher than the physical one, and a role of marketing is to raise that cutoff even further.
https://www.audiotherapyuk.com/product/oephi-reference-interconnect-cable/
Up to a point, there's an easily distinguishable sound and detail difference between cheaper and more expensive gear, given that you don't cheat (i.e. put cheaper gear in expensive enclosure), but that difference indistinguishable well before these "true audiophile" level stuff.
For example: I run a pair of Heco Celan GT302s. They are not something exotic. 100W per channel, adequately detailed speakers with great soundstage. The manual gives you a table: Wattage -> Recommended wire gauge. I got a high quality, 100% copper cable (from Acoustic Research, so nothing fancy) at the recommended gauge, and connected them. You can't convince me to get a better cable. It's pointless.
Do I enjoy the sound I get, hell yeah. Do I need to listen to my system instead of listening to the music, hell no. I feed the amplifier with a good turntable (which is 40 years old, shocker!) and a good CD player (which is pretty entry level for what's out there), and that's it.
That set will nail any person who likes to listen to the music to its chair. That's the aim of a good system. Same for personal DAPs and DACs. If you enjoy what you have, who cares!
I don't understand how that is cheating. Isn't it a better controlled experiment if the equipment looks the same?
If you want a good controlled experiment, create a literal black box, without any distinguishing features, or lose the box completely and give them an output (speakers or headphones) only.
Another bad thing is, sound is so subjective and experience changes between brands a lot. For example: headphone "burn in" is considered an hallucination, it mostly is. However I have bought a set of RHA MA750i earphones which changed from "This is not what it says on the box" to "am I sure that these are the RHAs I hated" in a month, because it's sound character changed so immensely. No other headphone I had in my life did that.
So, everything is so muddy, subjective and unreproducible. When a room's organization or floor carpet density can change its frequency response, you can't control anything. Moreover, every human's ear profile is different, so you can't be sure that their ear is hearing that the same (e.g. one of my ears have a notch in its hearing curve around mid frequencies. we don't know why it happened).
If anybody wants to learn some of the tricks which can be done to get better sound, please watch Mend it Mark's video: https://www.youtube.com/watch?v=-RJbpFSFziI
While the £25.000 price tag on that preamp is literal snake-oil level and the builder has the audacity to erase the model numbers of the ICs (and OpAmps) he uses, some of the methods he uses are legit and Mark explains them exceptionally well.
We all know that the aim of a good system is to blow your clothes off ;) https://www.youtube.com/watch?v=VNZ-nEGHDKk
I mean, I like Mikrotik products just fine. I happen to have a Mikrotik Hex S on my desk in front of me as I write this.
But scroll down and zoom in on the money shot here: https://hifi.nl/artikel/32753/Review-Synergistic-Research-Network-Router-UEF-The-traffic-controller-without-noise-on-the-line.html
And then, for comparison: https://openwrt.org/_media/media/mikrotik/rb760igs/pcb_top.jpeg?cache=
The difference in price between the Mikrotik box and the Synergistic box with the board is north of $2,500.
Also, this explains why I hear some birds chirping and bees buzzing in the beginning of the Pink Floyd's High Hopes (from Pulse). It's possible that the sounds from outside imprint on my wireless signal while streaming it.
Maybe I should buy this Micro^H^H^H^H Synergistic box and connect via it while listening to music. Of course I'll need Cat8 shielded cables, but it'll clear the sound, probably, I hope. /s