The Apogee Diva is hard to beat, given any other speaker, other than other big Apogees. Terry is right in saying amps that can power the Diva are plentiful. Given the Diva is a 4 ohm speaker, it has always been fairly easy to find tube and solid state amps that can drive the, Now, with the advent of digital, the very depths of these grand speakers can be explored quite inexpensively. I have the much more difficult to drive Scintillas powered by $3k H2O monos. this is a marriage made in heaven.