question on exhaust volume

I've read a couple threads recently with people saying their exhaust volume got much louder when the cats were removed. When I went from stock cats to high flow cats, the exhaust tone changed, but not the volume that I could notice. When I take out the cats this summer, I was expecting a tone change but I figured that the volume is pretty much as loud as the muffler. Am I mistaken? How much louder will my current set up of shorties, high flows, and 2 chamber flows be?

thanks,
Adam