They are very good headphones. They have an exciting tone to them, upper mids are a bit withdrawn but not as much as the 770.
650's produce more micro detail, the Denons are not good with micro detail but have a dryer sound so it may seem like the treble details stand out more but that's because they are a little elevated.
It also depends on the amp used. 650's depend on there amping more so than any other headphone I've owned. I liked the 650 with the Eddie Current tube amp better than the LCD-3's and it resolved better. If I had to pick one the more technical headphone with the best tonal balance would be the one I'd personally pick which is the 650.
650's produce more micro detail, the Denons are not good with micro detail but have a dryer sound so it may seem like the treble details stand out more but that's because they are a little elevated.
It also depends on the amp used. 650's depend on there amping more so than any other headphone I've owned. I liked the 650 with the Eddie Current tube amp better than the LCD-3's and it resolved better. If I had to pick one the more technical headphone with the best tonal balance would be the one I'd personally pick which is the 650.