My understanding of impact isolation is that you typically want an assembly/material with a higher impact isolation class rating. Therefore if you had to pick between concrete and wood as a floor assembly material you would go with concrete cause it has a high IIC rating? (I could have this backward, please correct me if I got this mixed up)
In general when it comes to good sound absorption, what factors below do I want high or low?:
SAC/NRC (I know these are coefficients and not necessarily ratings)
I think we want all of these to be high for good sound “design” in that I won’t be able to hear my noisy neighbors in an apartment building, but I often find myself getting the terms confused.