Hi deb,
I am trying to figure what the exact question is, as it is a bit unclear to me. Are you asking about a 3" dunlop topper being soft, or the two foams you mentioned?
Or are you asking when all three are combined, or the 3" dunlop on top of one of the two foams you list?
In terms of the which of the two foams you list being softer we can compare them bast on their density and ILD’s.
The 2.6lb 12-15ILD adapt foam vs 3lb 12 ILD Memory foam, both 1.5" in thickness.
When you analyze foams, the density of the foam can give you an indication of its firmness, with lower densities being softer. If we use that as our guide, the Adapt foam is slightly less dense than the memory foam, suggesting it will be softer.
If we consider the ILD values, they are both fairly close, so we might conclude that they are similar in softness.
While both foams are designed to be soft, based on ILD values, the Adapt foam is likely to be softer than the memory foam based on their density differences.
However, since the ILD values are nearly the same, or very close at the least, the perceptible difference in softness is going be minimal. Where you may find some discernible differences is how they react when you lie on them.
Adapt foam tends to be more responsive and bouncy compared to memory foam. It quickly adjusts to changes in pressure and provides a more immediate response when you change positions.
Memory foam, on the other hand, reacts slowly to pressure and heat. It molds to the shape of your body and retains that shape for a while, which can give a feeling of sinking or being hugged by the mattress.
It is important to understand what you are trying to accomplish when creating this situation. The Adapt foam will have a more buoyant feel and responds instantly to your pressure points, where as memory foam will slower to respond and will retain heat transferred from your body to the foam, thus making you warmer or hot.
Placing the Dunlop topper on top of the foam you choose, if only one, may make a difference in temperature, but you might want to consider talalay latex. A Talalay latex topper would generally feel softer on top of both adapt foam and memory foam compared to a Dunlop latex topper, due to its plush and buoyant nature.
However, both types of latex toppers can enhance comfort and support depending on your specific preferences, needs and specific goal is. Based on your conditions and pressure point requirements, it is likely that talalay would be the better choice.
Hopefully this helps, if I understand the question correctly.
Maverick