@theophile There is no “Absolute Sound” that can be verified, validated, and certified. The best that one could do is to compare the output of the source component to the output of the speakers and assess the accuracy there.
As for the room and acoustical environment, this is one of the biggest fallacies of the audiophile world and a complete misunderstanding of acoustics and lack of comprehension of the fact that our human brains have a built in sound arbitrator. To greatly overcome the room effect all one has to do is listen in the near-field.
I see unknowledgeable and misguided audiophiles spends some times hundred of thousands of dollars in bespoke custom acoustically “engineered” and treated dedicated listening rooms not realizing that they are doing more harm than good; with the end result in most cases being over-damped and dead sounding rooms. BUT beyond that is the lack of knowledge and understanding by the so called “acousticians” and “acoustics engineers” that don’t realize that the frequencies that they are attenuating/absorbing, diffracting, and reflecting with the acoustical treatments do not only effect the frequencies in their calculations that they are attempting to target, without realizing and understanding that these same discrete frequencies serve as partial components of the more complex waveforms in frequency ranges that they were not attempting to effect.
In most cases these “acoustically engineered” room look beautiful but sound worst and more compromised than typical domestic rooms and acoustical environments. It is all about vanity without any real understanding of the science of acoustics and sound reproduction in acoustical spaces.
Then there are the guys that attempt to add treatment at the first reflection point on the side walls as if the sound coming from the speakers is a ray of light flrom a flashlight, not realizing that every frequency has a different first reflection point and it is dependent on the polar radiation pattern associated with the individual loudspeaker’s design.
As I often see, there is the blind leading the blind, a lot of clueless people with deep pockets not realizing that they are doing more harm than good to the sound of their systems. I could go on and on but I will stop here for now.

