The most up to date discussions and highest quantity impressions are here: https://www.head-fi.org/threads/sennheiser-hd660s-finally-a-successor-for-the-hd650.862308
It’s a lively thread while this one mostly is historical (has some nice photos in the first post) and has some brief insights in the second post (FAQ).
It’s a lively thread while this one mostly is historical (has some nice photos in the first post) and has some brief insights in the second post (FAQ).
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