| I don't know but I've been told...inside the walls it's all about the mass as far as the STCs are concerned. More mass means more STC (regular air is pretty light weight compared with foam). You also need to make sure that your wall masses and your between-the-wall masses don't couple. They can touch (rubbing against each other), but impulses from one wall should not be able to excite the masses to move the other wall (which could happen if you affix the pink stuff to both walls with glue). |