I have looked and looked on the net for answer to this question. When I pulled up an Oak prefinished floor to replace with Maple, I noticed the roofing felt was very dirty, hardened by past spills (I am assuming) and THIN!. So I thought, I don't want this under my floor and should be replaced. Then I thought one day, this seems silly to do this step. Our childhood home had hardwood floors and no felt paper. Just good craftsmanship. I laid the floor and went at it and did two rooms. Now, here is where I think the answer comes into play and why underlayment is trivial for squeaks and pops.
- The second room is an addition added roughly 10 years ago. The other room was built originally about 25 years ago. After the floor was laid, the original build room has some squeaks to it, but the addition has ZERO. Both without felt underlayment and Maple 3/4 '' flooring.
- The old floor had nails from OSB to joists. AFTER installation, I have the same squeaks on the floor as I had when carpet was over the floor. The addition had screws to the joists in addition to nails.
- Also to add, the other rooms in the house that have 3/4' solid Oak have underlayment and I get the same types of cracks and squeaks in areas that aren't walked on often as I do on my new Maple floor without underlayment.
So, I believe it is about the subfloor wood in terms of creaking, not the underlayment. Also with 3/4" subfloor and 3/4" flooring, you have 1.5" of wood, not much will be heard through that unless you are some hard walkers.
P.S. Remember this is hardwood. It is and will have character.