IE 900

Sennheiser IE900s + JDS Labs ATOM stack (DAC/AMP).

I think it depends how you buy your IEMs right? When I'm looking for something new I'm looking for something that actually has physical hardware differences. My first pair was just a good all rounder, a nice baseline and a huge upgrade from anything else I had at the time. My second pair had bone conduction drivers which immensely improves the low end. While testing that bone conduction set I also got to try out some of the 64 audios with Apex porting. They're so comfortable to listen to. They're significantly more expensive but I would still consider them noticeably better. On the flip side I also got to try the Sennheiser IE900s at the same time and I think they're absolutely garbage for the price. It's mostly gonna be down to personal preference but if you keep buying IEMs that are essentially the same thing repackaged a new way, sets that aren't doing anything drastically new or different, the fall off is probably going to be closer to $300-400.

By that logic ie600 , tanchjim origin , ie900, mk12 , ea1000 and many others is not worth it.

Your impressions are totally valid. Psychoacoustically, the IE900 *can* feel like it has a wider soundstage than the HD660S2 — I’ve owned and listened to the 660S2 for a while as well. That spaciousness comes from Sennheiser intentionally sacrificing some presence in the mids, which creates the perception of more openness. But as a trade-off, you lose the kind of midrange richness you get with the 660S2. Of course, no IEM can really match a good open-back headphone when it comes to mids. I still remember how moved I was listening to Bon Jovi’s *It’s My Life* on the 660S2 — that texture and emotional weight in the vocals just hit differently. The IE900 can’t quite reach that. But for a lot of music, I do prefer what the IE900 brings to the table in other ways. I guess it all comes down to the trade-offs made in tuning and design.

IE600 or IE900 are some of the comfiest IEMs I’ve ever tried. Single DD but they sound incredible.

I like my IE900s - I think they look pretty slick!

The pros use ie600 or ie900 at the major tournaments, so you know it's legit for gaming.