So, how do you measure love? Or satisfaction? Or grief? Lots of things exist that cannot be measured.
And really, a lot of the things I mentioned are very hard to measure, because the data source (music) is very dynamic and inconsistent. But that's missing my point... audio equipment is sold using a meaningless measurement because it sounds important and is easy to measure. It has nothing to do with the clearly audible distinctions between different amplifiers.
Why do you think emotion can't be measured? As another poster mentioned, emotions are (unless you have religious objections) the result of physical processes, which can be observed with sufficient equipment.
How do you know something exists if you can't measure it?
>frequency range, balance, dynamics, phase shift, intermodulation, back EMF from speakers
All of those things you mentioned about audio are measurable.