With the limited information provided, I guess the undue soundstage height is due to disproportionately strong ceiling reflection. Due to low ceiling height, the reflected sound off the ceiling arrives at the ears very close to the direct sound of the speakers. The ears tend to integrate early reflection with the direct sound. This leads to perceived sound source broadening.
Just traps or absorbers would decrease the amplitude of the reflected impulse but would not spread out the reflected sound over time. The ceiling would still be very audible.
Combo tools (abfusors, skyline, hemifusors), or diffusors tend to help a lot in this situation as it would decrease the amplitude of the reflected and also spread out the reflection over the time domain. Having a softer, later reflected impulse tends to fool the brain into perceiving a boundary further away. I would think hemifusors or low profile skyline wound be excellent as they occupy less space and the slightly effective narrower bandwidth may limits beaming since listener is still close to the diffusor.
The brain composes the soundstage by reflection off all boundaries. If you have absorptive floor ( thick carpet), it wound further expose the soundstage broadening effect from the ceiling. Changing to wood floor would strengthen the reflection of the floor and would counteract the effect from the ceiling to some degree.
Changing the dispersion of the midrange/tweeter may also help. If it is an option, ribbon tweeters have broad horizontal dispersion but very limited vertical dispersion. This may yield a more stable/precise soundstage on the vertical plane but maintains a wide stage on the horizontal plane. Other ways including install a waveguide or using felt to limit vertical dispersion.
Good luck
Just traps or absorbers would decrease the amplitude of the reflected impulse but would not spread out the reflected sound over time. The ceiling would still be very audible.
Combo tools (abfusors, skyline, hemifusors), or diffusors tend to help a lot in this situation as it would decrease the amplitude of the reflected and also spread out the reflection over the time domain. Having a softer, later reflected impulse tends to fool the brain into perceiving a boundary further away. I would think hemifusors or low profile skyline wound be excellent as they occupy less space and the slightly effective narrower bandwidth may limits beaming since listener is still close to the diffusor.
The brain composes the soundstage by reflection off all boundaries. If you have absorptive floor ( thick carpet), it wound further expose the soundstage broadening effect from the ceiling. Changing to wood floor would strengthen the reflection of the floor and would counteract the effect from the ceiling to some degree.
Changing the dispersion of the midrange/tweeter may also help. If it is an option, ribbon tweeters have broad horizontal dispersion but very limited vertical dispersion. This may yield a more stable/precise soundstage on the vertical plane but maintains a wide stage on the horizontal plane. Other ways including install a waveguide or using felt to limit vertical dispersion.
Good luck