Hi dn,
Dominant layering can have a very different “feel” to a more traditional progressive layering where the softest layers are on top. It provides a firmer sleeping surface and the surface foam compresses less than it would if it was a softer layer and tends to “bend” more into the softer layer below it so it can still provide good pressure relief and “give” under the pressure points (as long as the dominant layer isn’t too thick and prevents the softer layer below it from “coming through” or compressing enough).
It is a good solution for people who prefer a firmer, “crisper”, or less “mushy” surface feel or greater freedom of movement and don’t like the feeling of sinking in directly to the top foam layer as much but still need good pressure relief that comes from underneath.
The “feel” and performance of dominant layering can be “nuanced” or changed a lot depending on the thickness of the dominant layer and it’s firmness relative to the ILD of the layers below it and the thickness of the softer layers underneath. It can reduce the amount that the heavier parts of the body sink down into the softer layers of the mattress (especially if the softer layers underneath aren’t too thick) but still provide good pressure relief under the pressure points (again depending on the thickness of the firmer layer).
In some ways it’s similar to an innerspring that has a variable spring rate that is softer with initial compression and firmer once the soft section of the spring is compressed and that has one or more layers of foam above the spring that are firmer than the softer part of the spring. It would be fair to say that it’s a different kind of softness with firmer overtones.
Some examples of other posts that talk about dominant (or dominating) layers in one form or another are here and here and here.
Phoenix