Most likely an artifact of your room acoustics and your specific vertical speaker driver configuration within the room.
Different wires and even electronics might change the timbre and change the perspective accordingly as SPL levels of the different vertically aligned drivers changes accordingly as well.
All speakers share the quality that room acoustics will affect timbre/tonal balnace to some extent, but I suspect the highly noticeable change in perspective at various frequencies is more due to the specific physical vertical driver configuration in your specific speaks.
Different wires and even electronics might change the timbre and change the perspective accordingly as SPL levels of the different vertically aligned drivers changes accordingly as well.
All speakers share the quality that room acoustics will affect timbre/tonal balnace to some extent, but I suspect the highly noticeable change in perspective at various frequencies is more due to the specific physical vertical driver configuration in your specific speaks.