Why is science just a starting point and not an end point?

Pedro, science has not failed at all. 

The most significant factor contributing to the sound of the speaker is it's frequency response in your room. Next would be it's dispersion/radiation pattern. IMHO every audiophile should have a calibrated microphone and the appropriate computer program to run some basic tests. This is the one I use  https://www.parts-express.com/Dayton-Audio-OmniMic-V2-Acoustic-Measurement-System-390-792
I am extremely happy with it. It is simple to use, very accurate and the program has some very useful added features like an oscilloscope.
In 30 seconds you can see exactly what your speakers/room are doing.
You can manage problems by moving speakers, with various acoustic treatments and finally with digital EQ. It is always useful to start with a flat system which means +- 5 dB, yup 5 dB.  Your system is lucky to be +- 10 dB! +- 1 dB would be amazing but you will never get there without digital EQ/room control. Once you have flat then you can adjust things to your liking. 
Next you can impulse test the system to make sure all speakers and drivers are aligned.  
Not only can you make your system way better but you can learn a lot about acoustics. This is an amazing value at  $300.00 There is not other "tweak" that is as powerful. It is so powerful it is not a tweak. It is essential.

Thank you Atmasphere. 

Listening is important only as it applies to the individual. I know what I like to hear but that might not be what you want to hear. 

An amplifier that measures beautifully in the lab might sound very different in different installations due to interaction with the speaker's impedance curve. These interactions result in frequency response changes that are easily measured.   My ESLs will change dramatically with different amplifiers and all of them measure well. The ESLs will go from 30 Ohms down low to 1 ohm if you are lucky at 20 kHz. There is no surprise here at all. You have to get an amp that matches your speakers. Some speaker will sound the same with practically any amp, a high impedance speaker with a steady impedance curve. 

Subtle changes are just as likely to be imagined as real. It takes careful AB comparison to be sure. You have to know the limitation of human hearing and proceed with caution. You can not just declare that one amp sounds better than another when the changes are subtle. When an audiophile makes a bombastic , declarative statement they are more likely wrong than right. Intelligent listeners do not make statements like this. Any obvious difference has a reason that can be measured and usually occurs in the realm of frequency response. 

There is always a reason a piece of equipment sounds better. If your ears can hear it than it can be measured. Measuring devices are quantitatively far more accurate than your ears. I did not say measuring equipment is more sensitive than your ears. I suspect it is but I do not know for sure.

Can anybody please tell me what Magister is talking about? He lost me several posts ago. Must be my dyslexia.

Mahgister, your legs may be doing the walking but your brain is controlling the show. So many things happen when you walk that you are totally unaware of. Your arms swing and the muscle attached to your pelvis tighten to keep the opposite side from falling when you pick your legs up. Same is true of hearing. 

@frogman, I seriously doubt people who dislike music spend serious money on stereo systems. Music preferences are purely subjective and a matter of taste. Stereo systems are not. If you want to improve the performance of your system an objective approach will get your there faster at much less expense.