I just sold a pair of Zu Essence and the first thing I noticed going to my new pair was that they don't have that EFFORTLESS sound that the Essence's had. Retrieval of low-level detail was astonishing with the Essence and I think that is what makes late-night listening (or in my case VERY early morning listening), enjoyable. Yes, they are 97 db/ 12 ohm which makes them very easy to drive. They had so much impact and dynamics at low volumes. I didn't know it until it was gone. Very underrated speaker.