I was just wondering if I replace my flexible 48" x 24" ceiling tiles with
the
hard type (much heavier) will I notice the difference in sound proofing?

I call all kinds of hardware stores to see which of the two is better for
sound. The opinions are split 50/50 between flexible and hard type. I
personally think the hard type are better, I wonder if replacing them with
this type will actually make a noticeable difference to be worth replacing
them?