Do I need taller speaker stands?

[krott5333]

At my couch, my usual seating position, my ears are at 39" height. I'm about 12 ft from the speakers.

My speakers are on 22" stands.

Today I sat down on the floor in front of the couch and everything improved, especially imaging and upper midrange. On the floor, my ears are at about 29" and I'm approximately 11 ft from the speakers.

Do I need taller stands? How much taller?

See pics for current driver heights.

 

[Taddpole]

Tweeter at ear height is the general advice.

 

[Milan237]

Do I need taller stands? How much taller?

The high-frequency tweeter of your speaker should be at the level of your ears because these frequencies are directional and even a small deviation in direction will affect the perception of the sound.
This is elementary physics, read a little about the basics of acoustics, with these definitions and everything begins, perhaps you will discover something new because to listen to quality sound should be able to)