Originally Posted by Fjodor2000
What I wrote previously
should be sufficient: "professionally performed ABX tests involving a large number of people? [...], do you have any links to those tests?"
As I posted previously, the above was a double blind test. Here are the results
8 persons participated on this test
14 chose the "A" system as the best sounding one
10 chose the "B" system as the best sounding one
14 were not able to hear differences or didn't choose any as the best
Since it is obvious you did not read the link, System A was the Behringer A500/Sony CD player with System B being the Classe' amp with Wadia CD transport/20 bit DAC.
The room was acoustically treated including the ceiling, all the information is in the link.
You could claim the Classe' amp was not good enough for the Wadia CD transport/DAC--those players run over 10,000 Euros... You could claim the MIT interconnects were not good enough but they competed against a 15 foot RCA cable purchased at a gas station.
The tomshardware test was interesting, he ran bench testing on all the DACs first. He found flaws with the 2 buck chip DAC built into a motherboard--but the two audiophiles with hearing tests done to them could not tell the difference. The sensitive testing equipment showed a difference so they wondered if human hearing could identify the flawed DAC. They could not. Tom has a PhD in computer engineering and has full test gear to verify computer performance (He was the guy that found the flaw in the original Pentium chip math processing)
Technically, all DACs sound different--even the same DAC made the same day in the factory. Ultra-sensitive test equipment will show this but your ears never will. Sorry, the ability of the electronics have far exceeded the human ear to tell a difference and this happened many years ago. The same applies for amplifiers and interconnects/wires/power cords have never sounded different if they were spec'd to their proper use in the first place.
As I stated, I did a single blind test 25 years ago--but I was in my early 20's, my hearing was much better than it is now and I was curious. My results were the same as the audiophile group in Spain with 38 people. We used the top of the line Yamaha VS the bottom of the line 4 year old Sony--and could not tell the difference. We used a switch deck, it was single blind and we used 3 different amplifiers and 3 sets of speakers. Our testing was not to double blind ABX standards but the object of the test was to find the difference in speaker cables, CD players and amplifiers--could we find the differences in them? Granted, we ran some rather nice equipment against each other and did not use 15 foot RCA cables from a gas station. The differences were not as extreme as Matrix performed but the results were the same.
I don't know about you, for me 38 audiophiles getting together and actually agreeing on testing of their equipment is very convincing. The worst decent system VS the "best" system removes all doubt what the capabilities of modern equipment can do and the human ear's ability to detect it. Throw in all the testing AES has done, the research the medical community has performed for decades and there is plenty of information to inform you what you actually require.
Level matching equipment is a pain in the butt, it is not easy to perform accurate testing but if you want to know the truth...that is how to do it. If you prefer to believe you can hear the differences in something that is extraordinarily accurate then pump it through speakers that have many times more distortion and uneven frequency response--that is then wrecked by room acoustics, feel free. Maybe you are the freak of nature that medical science would love to give a hearing test--because that person has not been discovered.
Then again, many people will claim that sound quality is the reason they blow $10K on pretty blocks of aluminum when they don't need that for sound quality reasons. Have no idea why they just don't say they like big blocks of aluminum, the heft, the switching and the craftsmenship. Personally, I have always preferred to hide sound equipment, not to make it obvious with a giant audio pile. My HT system for the most part is hidden with only two speakers being immediately obvious. It is a great system to flush out audiophiles, many of them can't stand hearing something without knowing the equipment. My speakers use custom built magnetic grills with grill cloth to match the furniture or walls so they have no idea what the design of the speakers are let alone what brand. Can't see the wires either, all that stuff is hidden. My days of having amplifiers, sources and cables front and center are long gone. My TV takes up enough space, the subwoofers gobble up a lot of space (although they look like furniture) I have no want to display a bunch of metal boxes with flashing lights which mess up the darkness when watching a movie. I want great sound that vanishes when watching a movie, I get the sound quality high enough that I don't think about it anymore. I'm almost there, if I concentrate on the sound and not the movie--there are a few issues but I have those solutions which will require more custom built enclosures and grills. All part of the hobby, once my new center is done and I can get three subs to play nice, that part is done. Since it is a hobby, the Atmos elevation front stage should prove entertaining to custom build angled speakers painted/grilled to match the walls and adjust to work properly.
The broad view is good sound, experience, testing and R&D indicates the same thing that most product use portrays. Put the budget where it counts, don't waste time/money/effort/space on things that don't matter and always remember, with electronic devices the target is always moving so define what you need to set the bar to what works for your needs. Once you know what you need, then decide the features, build quality, looks and space you are willing to give up in your quest. If you want to get the best sound, then you'll fall down the rabbit hole of room acoustics, measurement and getting the speaker designs that fit the downsides of your room. If you ever feel that your system is the "best", run an REW sweep and prepare to embrace failure. If you are the type that don't enjoy bad news, join the club that measurements don't matter, your ears are golden and any audio problem can be solved if you throw enough money at it. Sure, the second choice is expensive but it saves a ton of time! I'd much rather throw in a new box than move heavy speakers around--or swap a cable instead of solving sub bass peaks and suck outs.
Enjoy the read on the testing in Spain, the testing done by Tomshardware is tedious to read with many, many charts and graphs but you asked! Other sources are the Audio Engineering Society as they have plenty of research as you would expect. As you get deeper into any hobby be it cars, power tools or boats--eventually you'll need to do more research to increase your enjoyment of the hobby. As with cars or power tools, purchasing a race car does not make you a race car driver or owning a $25,000 set of tools does not make you a furniture builder. The same holds true with audio equipment, once you have what you need then the hard part arrives--proper setup, calibration and testing--retesting, change the setup, change the room and so on will keep you entertained long enough to start over again when your needs change.
This is a hobby after all, get off the squirrel cage and enjoy it.