There are many full range speakers with tweeters positioned higher than the ears level. Also, in many live performance in small rooms, the singer's voice would come above the ears level when you sit in a chair.
So, I am not sure how accurate the general rule (tweeter height == ears level) is. But, you may not have it so higher or lower than the listening level. ;-)
So, I am not sure how accurate the general rule (tweeter height == ears level) is. But, you may not have it so higher or lower than the listening level. ;-)