For the most part I believe Height is changed by the the amount of information being put out, volume, the dynamics of the recording and room reflections. Change any of these and you may hear a different size sound stage. If you would like to try somthing for fun. Get a couple of sheets of stiff foam board 2' by 8' about 1.5 to 2 inches thick and stand them up between your speakers. Then move them around between your speaker. Then cover them with a blanket or sheet and do the same thing. When you move it in a front to rear movement from the wall see how the sound stage changes (height). Get it to where you hear somthing you like then change the volume. Next change the surface (add the sheet or blanket or remove them).
Good Luck.
Aknorth
Good Luck.
Aknorth