Yinyoo KZ ZST.
Truthear x Crinacle Zero Red
Letshuoer S12 Ultra. Running off a FIIO BTR15.
I didn't think I would reach my personal endgame after only 3 sets of IEM's.
I got the ZST's 2 years ago because I was looking for something that would fit my ears. Regular flathead earbuds just fall out of my ears. This was long before I knew anything about audio.
I was ready for how good these sounded. Not only did instruments have more detail, but I felt like I could hear the distance between instruments! (soundstage and imaging) I started hearing new details in everything I listened to.
Long story short, I fell down the youtube audio rabbit hole, mainly with Dankpods, Crinacle, and The Headphone show.
I ended up getting the Zero Reds 1.5 years ago after looking around this sub and hearing about how good their bass extension was. (as a tuba player, I'm a bit of a bass connoisseur)
Everything about the reds was better than the ZST's. The bass was deeper and more detailed. The treble was deeper and more detailed. I felt like I could physically point to where instruments were in my room. I also got the BTR 15 with these because I wanted something that could drive my AKG K702's better than my laptop.
The Reds were fantastic... Until the right monitor just stopped working after a year.
Around this time, I was getting curious about Planar magnetic IEM's, The Letshuoer S12 Ultra had recently come out, and after reading a few reviews, I decided to give them a try.
I could not believe how much I liked these. The S12 Ultra is awesome right out of the box, but they can take EQ like an absolute champ. The bass is clean, tight, and completely free of distortion. Every bass instrument sounds amazing out of these. The mids are clean, present, and lively. Voices are especially detailed and lovely. The treble is great, although not a huge step up from the Zero Reds (which had great treble response because of how V shaped they were). However, I noticed that cymbals stopped sounding like hissing and started sound as detailed as cymbals do in person. I could even pick out the wooden tapping sound that the drumsticks made when they bounced off the cymbals.
I know that 3 IEM's isn't a lot, but I literally cannot imagine anything sounding better than the S12's. Unless they break or I loose them, I don't think I'll be buying any more IEM's for a long time.
Just thought I would make this post to sat thank you all for answering my questions.