I haven’t heard the X9000 yet but I agree with you on the CRBN. I visited NYC last month and was so excited to test out the CRBN at Audio46. I was overall disappointed. The treble was noticeably recessed which I feel defeats the purpose of spending that much $ on an electrostat. However they definitely weren’t using an ideal amp.
I haven’t tried any other $3000 closed-backs but I really don’t see any closed-back being worth that much unless for some reason you prefer a smaller soundstage. To me the only benefit of closed-back is isolation. If I’m already alone in a quiet environment then I will always prefer open-back. I work remote 90% of the time so I’d like to get myself a high tier electrostatic headphone next year.
I’ve had the Stellia for a few months. I love it with EQ. Without EQ, I would only recommend it to bass heads. It’s far too dark for me. Definitely not worth $3,000 imo but it’s not hard to find it on sale.
Cool kids never have the time