These are not more balanced than the FXT90, with greater extension on either end. They lack that harshness/edginess to the upper registers that I found previous gen JVCs had, like the FXT90, 3X, 1X, FR201, FX101, etc.
They are quite bright, but are MUCH smoother and more refined than the FXT90. Despite being bright, there is a warmness to their signature that counters that treble emphasis quite nicely. I would say these are more of a u-shaped than v-shaped since mids aren't really pulled back much if at all. In direct comparison to the FXT90, the FXH30 sound much more lively and dynamic. The FXT90 have pretty boosted mid-bass to my ears. The FXH30 dial that back and boost subbass making their bass presentation more even throughout. The T90s have a wider soundstage, but depth would go to the FXH30. The 30s also do a much better job of accurate instrument placement, separation, etc. which is why they work so well with metal. You miss absolutely nothing, even on tracks like Razor's "Sucker For Punishment" (there are better examples but that was the only thing I could think of at the time).