Speakers depend on listening distance first, room size second.
If you are in a big room and a small room, both listening at the same distance, what is going to be different? Well, let's see, first, you are going to hear the sound from the speakers. That volume will remain constant. If there are walls close on the left and right of you, the reflection of that sound will make the sound louder and sound different. Then, the sound reflected from all other angles of the room will eventually reach your ears, adding slightly to the sound level.
So, sitting at the same distance in a big and small room, the small room will sound different, and possibly "fuller" because the reflected sound will be louder, giving a surround type effect. In the bigger room, the speakers might sound more directional and a bit less loud.
So really, if the listening distance is constant, a big room and small room are just going to sound different. Not really a volume difference, but an acoustical and imaging difference. Once you start getting into this category, you are getting more into acoustics, reflections, absorbtions, room characteristics, etc.
Kind of a big bone to swallow, but, it's kind of hard to convey this effect on forums without just dragging speakers into different rooms and trying them yourself.
Those are just my two cents. If I have made a controdicictory mistake creating a black hole sucking all of my points in and collapsing my entire argument, please let me know.
But, I think you are there in terms of understanding.
