I think we are on the right path here. Phase is most important at cross over points particularly with sub woofers. I think otherwise frequency and amplitude as they relate to each other are critical in producing a refined image. It is true that 90% of what influences this interrelationship is the speaker and how it performs in a specific location in a room. To create an image it is critical that the sound from each speaker gets to your ears at exactly the same time at exactly the same volume using say a test signal from dead center stage. Now as the signal moves back and forth across the stage it's arrival time and volume change giving you it's position in space. I think that is something we can all agree on. Now, as I move a speaker in the room it's frequency response curve changes based on it's interaction with the room. The response of two identical speakers is never exactly the same because they can not occupy the same region in space. So, a pair of identical speakers can be 2-3 db different at any part of the response curve. So as an example take a violin. At 500 Hz it is say 2 dB to the left. At 1000Hz it is dead center then at 2000 Hz it is 3 dB to the right. You have different parts of the violins frequency response coming from different points of the stage blurring the image. It is not so important to have a flat frequency frequency response, It is important to have exactly the same frequency response. The only way I know of to achieve this is with high resolution room control. Other than this the only other issue that can confuse the image is early reflections that have to be minimized as much as is reasonable in any given room. You do not want a speaker blasting in all directions. The result of this is that you have more early reflections to deal with. You want to control the dispersion to create fewer early reflections.
Obviously none of this has to do with amplification or signal sources. The image is embedded in the software but it is up to the speaker and room to interpret it correctly.
Obviously none of this has to do with amplification or signal sources. The image is embedded in the software but it is up to the speaker and room to interpret it correctly.