Dan's Data has posted a review on Beyerdynamic's DT 660 and DT 860 headphones

Beyerdynamic's DT 660 and DT 860 headphones are not just cutdown versions of its superb DT 880s. They're big and they're not cheap, and they sound good, but they do funny foldy party tricks, and some stuff about them is
just plain weird.

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