You would have to be able to distinguish low-level spatial information from the much higher volume level of the music -- by measurement on a music signal. Though nut to crack for measuring devices, child's play for the intelligent human hearing.
An interesting topic that I have pondered on for quite a while.
Dynamics, frequency response / tonality; no problem.
But soundstaging / openness / spaciousness..... Hmm, not so easy it appears and not something I've seen those that like to measure address to any great extent.
I've certainly heard equipment that seems to my ears to add an artificial spaciousness to the sound - Philips X2HR headphones come to mind - so maybe Philips have an insight.
