Superlux Hd440 is on a class of its own. To Superlux fan who are already familiar with HD660 sound will be delighted to listen to HD440. It is a much better version of HD660. Well i would not say better because it has an entirely different sound signature from the usual Superlux Offering..I think it has the best midrange among the Superlux. It is clearly a mid centric type of headphone.
Let me settle for a week first before giving any more description on the sound quality:)