It wasn't a collab it was the candy cover oops. I saw it as some sort of edit on youtube and that's when I noticed some of the problems. Basically she's lost her consistent support, she was the Mamamoo member that was most consistent throughout their career and she's lost her coordination with C5s. I don't know if it's nerves but she's always been the one with the strongest mix but now is very closed, less strong, and can be shallow on her lows. It's low AA for sure, but how low is the question. I think her best moments are like Pink Fantasy's Yechan honestly, she's gotten some okay mixed notes but nothing compared to her earlier level in Mamamoo. Regression is common, it's possible she is going though something hard and her vocals have been effected, and she will later improve. I'm just surprised because I initially thought her solo had a lack of proper support because she was trying for indie style in that and lowering her larynx to get a more emotional sound but no it seems to be an actual issue....
Solar has basically been fixing her problems with her vibrating jaw, tendency to be really chesty and her high larynx problems. She tends to go all out when belting but is now in check with her technique, and more importantly working on her air pressure problems in her highest range. I think she could be above AA and be fighting for AA-C if she continues this improvement, it's a pretty significant one because those problems held her back. Even her predebut auditions had this problem with Solar singing Whitney I believe, and it's a good improvement to make. I think again, it's been happening for over a year now. Slow and steady added up. I think at one point she will reach Raina level.
What I've always thought about their mixes was that Solar always uses so much volume and pushes alot to mix as she ascends in the 5th octave, Hwasa just kinda strains alot up there and is really chesty, and it's obvious that she has the least range up there compared to Wheein and Solar (I don't think I've ever heard her belt above E5), and Wheein has always seemed to perform the best up there and have the most ease up there, she has always seemed to be the most balanced and well-rounded although she is the one out of the 3 of them with the most tendency to be nasal too. I'm not a vocal coach/expert or anything but I do enjoy reading about vocal technique and stuff, and that's kind of what I've gathered from being a fan of theirs for a while.. It's a bummer to hear about Wheein's regression, hopefully she's able to improve.. But really great news about Solar!