Originally posted by Hydro Boom:

alr thank you all I was confused if I had missed a room

the entire reason, as good programmers you DON'T do this. Apparently they did not read the memo. I have written before about it. It leads to confusion, unnecessary chances. Designers don't typically put you in such a predicament. It's bad judgement. And also you can get sound from the surface in some, esp ones that cross a biome border(below ground).
In fact silly enough, but technically true, you can cross a biome underground for the first time and get the banner notification. But weather sounds do sometimes play down there. Which I also have written about. And just happened to me today. Winds that are normally part of the Mtn biome can be heard underground in the chambers. ;p

Yes, they are ambient sounds. Each location, each environment usually have one day and one night ambient track. But none seem to have any day-cleared and night-cleared track.

If only devs could set the functionality up, this could sure become a low-priority polishing feature, or a good idea for a mod.

In the swamp, my friend and I experienced the same thing. Then we realized that the crypt we were exploring was very close to another one. We were hearing enemies from the next crypt over.

I imagine it as coming from rooms beyond the collapsed tunnels or blocked doorways that we cant get through. Think of it as the gated community of the barrows. The upper class undead don't want vikings stomping through their crypt, smashing their minions, stealing their cubes (it's cold forever without the cubes) and eating their mushrooms.

It's ambient noise tied to the area.

The Swamp has similar noise ambience as Burial Chambers. I often hear things falling into the water and what sounds like leeches under the mud. Frost Caves also have a continuous sound ambience, though to a lesser degree.

The ghosts of the ghosts, its a double haunting.

Just finished one with a skele stuck in a wall. I can see it doing damage to something but it's not in the hallway or any of the rooms. It's like the graydwarves that are stuck inside rocks. Funny stuff.

I was in the crypt next door. Sorry for being loud.

Procedural generation? Maybe something stuck or an inaccessible chamber.

Maybe ambient sounds for funsies?

That's all i got.

Might be a room you missed but there are some ambient sounds like that.

Some burial chambers have lower floors.

There'll be one corridor that slopes down sharply, and might be a lower level.

Even in a completely cleared burial chamber you still have those sounds as ambient noise. Cleared burial chambers can still act as a spawn point and can produce skeletons in the outside environment.

You'll notice the same thing happening in cleared out troll caves in the black forest, crypts in the swamp (except they'll have dragur and blob sounds) and cleared out frost caves in the mountains (with the same caveat about biome specific creature sounds.)

You will also notice that the swamps have leech sounds near the water even if there are no leeches present. Just like you will hear branches snap in the meadows and black forest even if there are no creatures that you can interact with present.

Yes, it's just ambient noise. Creepy idnit .

alr thank you all I was confused if I had missed a room