Adding a temporary door

Question

I host my brother for the weekends sometimes and he sleeps in the basement. There is a doorway by the stairs down to the basement, but there is no door of any kind there. As such, when he's sleeping down there, he can hear all the noise on the main floor.
I want to put up some sort of sound-blocker, like a door or something to make the basement a more livable guest room. However, I don't really want to hire someone to install a door there, I don't think the space is so conducive to installing a "normal" door, and I don't want a door there the rest of the year when I'm not using it as a guest-room.

Thoughts I had:

1. Install an accordion door in the doorway. The problem with that is (a) when the accordion door is "open" it will still block a bunch of the doorway, such that you'd have to walk through it sideways, (b) this would have to be a permanent installation.

2. Using a removable pole/rod (like a rod on shelf pole holders that let you put the rod on and off) across the top of the doorway and hang some sort of curtain to block the doorway. I think this is a better idea, because it's much more temporary - I could just take the pole out of the wall and the doorway returns to normal.

The questions I have are:

1. Do you have a better idea about how to block sound from going to the basement?
2. If you like the curtain idea, what kind of curtain would I need to get, to best block sound? Meaning:
   • what material/type of product would I need to get as a curtain?
   • Also, how could I make the best type of seal, while still being able to open and close the curtain.

Answer 1

Alternative solution: give your brother ear plugs for the duration of his visit.

A pole with a thick curtain can muffle the sounds somewhat, but not much and the curtains needs to be very thick and heavy. All the sounds that are transmitted through the ceiling/floor (any walking around, opening and closing doors, creaking floorboards, moving objects over the floor or letting objects fall on the floor) will be as loud as without the door / curtain / whatever.

Ear plugs, on the other hand, reduce all sounds that reach the wearer. Foam plugs are comfortable to wear while sleeping. There are also soft silicone plugs designed for sleeping that are reusable and intentionally let some sounds through (especially the alarm clock). I found them to be uncomfortable while lying on my side, though.

Some people are unnerved when first using ear plugs to sleep. They may notice some tinnitus-like phantom sounds when the plugs eliminate all sounds from outside. These people should use ear plugs that let some sounds through, instead.

My personal experience: you can also hear the alarm clock through foam plugs if you're not a very sound sleeper. Some plugs (like cheap bulk buys from the hardware store) are less effective at reducing sounds than high quality ones like Ohropax. Bigger plugs (like Ohropax soft) are more effective than smaller plugs (like Ohropax color or mini).

(I'm not affiliated with Ohropax, but I have used their products for years to sleep well.)