@mkddm11,
I finished a dedicated room last year and used isoblok to add mass. No experience with resilient channels although is was seriously considered. I had to keep noise in the room as to not disturb a medical student, then deal with the noise or frequencies within the room so two distinct goals. If you are still in the planning architect phase, best to keep noise in the room is a double wall, air space in between. On the inside wall, to inhibit wall resonance’s We used to great effect, different stud spacing from the outer wall, mass loaded vinyl on the inside wall, then two layers or 5/8 sheet rock sandwiching a layer of green glue. Having different peaks in our roof architecture, I avoided 90 degree angles by vaulting the different peaks. For tone, using wood in the ceiling or walls (many prefer cherry) as an advantage. If windows involved, keep well above listening height and triple pane with unequal space between the panes. Treatment with heavy weight pleated drapes can be added to effect. After design completion, and you have minimized the rooms ability to create standing waves and suck outs, then resonators to target specific frequencies. If there are no openings into the home to allow bass waves to escape, and therfore dealing with a sealed environment, then start with and plan on 4 floor to ceiling corner bass traps with diffusors throughout the room. Expert consultation can also be obtained from acousticsciences. They can assist you with the RP60 so as to not over or under treat your particular room characteristic and design choices.
The above build I thought superior to resilient channel methodology for my intended purpose. With either method, inside the box will need a bit of post construction expertise. My 2 sense. Have fun.