Well, I have Scintillas powered by X600. These will give impact down to 20Hz. The mids are incomparable except for Quads. The highs are perfect beyond hearing. They produce the music as was recorded. When the recording is first rate, the Scintilla sounds seamlessly natural from 20Hz to 20KHz.
Scintillas give full performance even at low volume.
I have never heard another speaker that can do this. The Apogee Diva and Duetta are wonderful too.