It is the prominent treble that enlarge the soundstage. But for me those treble caused to sell the PRO 2900 and 900 after buying the Signature PRO and DJ. Both have absolute no treble sybilance. And the PRO 550 is still with me because it is comfortable and also has this good soundstage as being closed. It is still my main can for PC gaming.
Hmm, interesting. I've never head that before (soundstage being due to prominent treble). Well I won't argue with you on the SigPro/DJ. I haven't heard the SigDJ, but the SigPro is a step up from the 900 in many ways except bass impact so saying it's superior to the 900 is understandable at least. I just can't see the 550s being any better than the 900s having heard both but to each his own I guess. If you enjoy them more than you did the 900s, that's great as they are cheaper.