No way, IMO the HD800 are far superior that the ED10. They are the best in soundstage presentation of all dynamic headphones IMO and clearly NO VEIL. I have mine with an OCC Copper cable and replaced the internal connection wire between the connector and the driver with also the same OCC Copper. IMO sound magnificent. They are my favorite open dynamic headphones.
Copper wire on the hd800s?!?!? That's almost an insult to the headphones considering they already have an occ silver over occ copper core wire. From what I understand of sennheiser you need to bring out the highs and improve clarity not diminish it. I'd use copper to dim brightness and enhance the midrange. I mean absolutely no offense by the way. This is all MY opinion.
To my knowledge the HD800 cable is not OCC Silver over OCC Copper but a common Silver Plated Copper cable.
To my hears it did made HD800 a little harsh and bright at the top so the WireWorld OCC Copper cable really smooth them out and improved the midrange and bass.