What's the ideal height for bookshelf speakers?

thanks everyone, I appreciate it.

In my room, my Sonus Faber Signums sounded poorly atop the 28" SF fixed height stands, but when I put them on 24" stands there was a great improvement in overall balance and significantly improved bass. This was surprising to me as when I owned EA I's and the variable stands they sounded great at the 28" level which I arrived at by trial and error, and never knew the height of, until a friend asked. I also had Concerto Homes and they sounded as good as they could sound on the 28" stands.

So what I'm saying is: try different heights and positions, and hear for yourself what works best. Then you will really know.

Usually the Tweeter is at Ear level!

According to Sonus Faber, the optimal height for bookshelf speaker placement should be to have tweeter stays at the level of your at your siting position.

Need 2 persons to measure.

Try to find an adjustable stand. The height of the speakers can make a dramatic difference in sound (I had a pair of Sonus Farber E.A.II's, and they were REAL tweaky about height adjustment, although I can't comment about the vertical dispersion of the Paradigm.)

THE IDEAL STAND WOULD HAVE BEEN THE PREMIER J-60'S WHICH ARE 26" TALL.

That's fine. Assuming your head is not in a brace, its relationship to the tweeter will always vary a bit.