Originally Posted by Skippard
Are you saying that 1/4" rigid foam under OSB could cause serious acoustic problems?
I am in a similar situation, where I am trying to plan out flooring options for the basement. My goal is to get off the cold concrete with a minimal effect on acoustics in the HT. I am thinking of using Planton or Dricore but the cost is a little difficult to justify. 1/4" RF would be a lot cheaper, but not if it would be a serious hit to room acoustics.
it won't cause problems with sound inside the room, and it will help with higher frequency impact noise, particularily on concrete or something extremely heavy/hard, where high frequency noise is more of an issue.
but, yes, it could cause loss of performance over some freq range due to a resonance. when you put air cavity or something springy into a structure to decouple it, you get this resonance as a side effect. unavoidable reality of the situation.
in this case i think rubber mats with mass + generally less prone to this resonance are a better choice in lightweight floors. in heavy (masonary/gypsum concrete, etc.) floors, the choice of underlayment is less important.
so no, it won't hurt room acoustics, the considerations are only sound isolation. and in situations it can be helpful for that, but its not a universally beneficial product.