That's the good news for all the firms who use one-tube design. So Crack may not loose any soundstage (maybe a few percent), that's good to know.
Great! Hopefully not too expensive :D
Yeah, because of that diminished treble in 650, even if it's more detailed in lesser frequencies, I'am happy with 600. If, then next step would be HD700 but I don't see that yet (too expensive).