Head phone sound is different than sound in our rooms. Both have their good and bad points.
Head phones seal our ears with a small oval shaped room. Inside that “room” is a small speaker that produces sound energy and fires it directly into our our outside ear. From there, the sound travels into our ear canal and then finally into our inner ear. We hear bass energy, middle, and high frequency energy all evenly portrayed in the two channels that are wrapped around our head.
Were our ears designed to have sound that close to it and at those pressure levels produced by headphones. If they were wouldn’t they be smaller. No need for three or four inch ears if the sound we hear is generated from such a short distance away as with headphones. No, our ears were designed to hear sounds from all directions and at some distances. Men have larger ears than women. This is probably due to the way men used to hunt for food. Hearing everything from all directions when hunting for food, enabled man to bring home the dinner rather than be the dinner himself. A larger sound receiving instrument was needed to allow for selective hearing and localization of predators.
Do headphones produce a sound stage in front of our head. I have never experienced that with headphones. I have experienced both left and right channel separation, but no sound stage. Headphones do not have a sound stage and therefore do not have any height, width, or depth to their sonic presentation.
They do have definition. Headphones portray every sound in detail. One can hear all the instruments and vocals with distinct separation between them. If we can get our rooms to have that instrument and vocal separation coupled with headphone like clarity, we will have achieved our room acoustic objectives.
A room has space and the sound source is at a much farther distance from our ears than headphones allow for. We can have a small as is the case with near field listening or monitoring. We can also have a large sound stage depending on room dimensions and the correct balance in the room of acoustical treatments. A room and the sound produced in it is easier for the design of our ears to interpret. The music or sound reaches our ears in a way and manner that allows for localization and spaciousness to occur. With this spaciousness, we now can have information going into our brains that has much more data in it than just headphone sound. We have room sound and room sound is closer to free space sound which is probably how our ears evolved into the size and shape they have today.