Hey all just got the HD-590... Pretty good sound so far even before break-in but MY OH MY do they ever leak sound... 2x as much as the HD-580 I'd say.
The are louder outside the phones then when you are hearing them unless my pair is screwed up don't know.
yes, the 590s are very open. I don't think they are defective. If you look behind the metal grill, you see the actual driver. What you are hearing is the magic of physics, the same amplitude signal is being created (though 180 degrees out of phase) on each side of the driver. With nothing to block that, it just goes out into the room.
People very often are concerned their headphones are broken. Nearly every day someone posts here about their headphones, and muses that they might be defective. Companies DO have quality control, defective units making it into the public is possible, but very unlikely.