The_kid is right. 90db @ 6ohms. And my 55wpc amp did sound very good. I've learned, however, that input sensitivity ratings are not necessarily a good indicator that the speakers will be well-served by lower-power amps. Consider this... I have 5wpc S.E.T. amp. I can't even move the drivers on the GPs, but I can play my Paradigm Studio Reference 60's magnificently with it. Both are 90db.
Cheers.
Cheers.