It’s just the nature of those shells, I’m thinkin’. I was a Sonor endorser for 15 years and I still have 7 of their kits, including 4 Delite kits. That S-Class Pro kit is the only one of those that I have and it’s the only one of the 7 kits whose rack toms just have to be tuned WAY down before they’ll open up, even off the mounts. Nature of the beastie, methinx. Interesting phenomenon, though.If you've already tried the Emperors and nothing changed..... I would'nt waste money on heads.. . I would feel bad if you went out and spent money.. LOL ....... But there has to be something going on..... and the only thing left.. is MAYBE the room you are in.. I've had horrendous issues with THIN SHELLED kits getting the sound they should.. then I change to a different room and all of a sudden.. it's on............ The other thing is.. check the diameter of the tom shells from opposing angles to see if they are way out of round and also if the shells lay flat....... like I mentioned.. those are sourced from the KHS/Mapex plant and not that it means bad things.. but just to check it out does'nt hurt.
ETA - here’s a little taste of the 22 and 14 floor. Like I said, I love the kick and floor toms. I had a 12 mounted but only played it once.