# Sound between two rooms - closing which door affects the sound most?

• I
• NEWBIE1212
In that case, the sound will be attenuated by a factor that depends on the surface area of the wall that is "seen" by the receiver, and that will depend on which wall the receiver is near (assuming the walls are not identical).In summary, in the scenario of two identical rooms with a space in between, sound emitted from one room only can be lessened by closing the door of the listening room rather than the door of the sound emitting room, as stated by the Rayleigh-Carson Reciprocity Theorem. However, this may not apply in cases where the sound is high frequency and the walls are sound absorbing.

#### NEWBIE1212

Imagine you have two identical rooms opposite each other with some space in between. (Ie two rooms across from the passage or two rooms leading off of another room). Sound is being emitted from one room only. Would closing the door in the room where the sound is being emitted from or would closing the door of the other room (listening room) result in less sound being heard?

My logic is that closing the door of the listening room would have a greater effect than closing the door of the sound emitting room.

Delta2
Welcome to PF.
NEWBIE1212 said:
My logic is that closing the door of the listening room would have a greater effect than closing the door of the sound emitting room.
Why do you say that? (you may be right, but why?)

davenn
berkeman said:
Welcome to PF.

Why do you say that? (you may be right, but why?)
It cannot be any different, because if you interchange the source and receiver you must always have the same overall loss. In radio engineering this is known as the Rayleigh-Carson Reciprocity Theorem.

For the idealized problem, reciprocity should answer the question. It might be fun to think about whether there exist any real-world conditions under which reciprocity might break down in across the two rooms.

I think you need to be more precise about where in the rooms the emitter and listener are located.

If the sound is high frequency so that the ray approximation is valid, and the walls are sound absorbing, I don't think reciprocity applies.

## 1. How does closing one door affect the sound between two rooms?

Closing one door can significantly decrease the amount of sound that travels between the two rooms. This is because the closed door creates a physical barrier that blocks and absorbs sound waves, preventing them from passing through.

## 2. Does the type of door affect the amount of sound that is blocked?

Yes, the type of door can make a difference in how much sound is blocked. Solid doors tend to be more effective at blocking sound compared to hollow doors. Additionally, doors with weatherstripping and a tight seal will also help to reduce sound transmission.

## 3. Which door should be closed to minimize sound between two rooms?

The most effective way to minimize sound between two rooms is to close both doors. However, if you can only close one door, it is best to close the door in the room where the sound is originating from. This will help to prevent the sound from traveling through the open doorway and into the adjacent room.

## 4. Are there any other factors besides doors that can affect sound between two rooms?

Yes, there are several other factors that can impact the amount of sound between two rooms. These include the materials and construction of the walls, the presence of windows, and the use of sound-absorbing materials such as carpets and curtains.

## 5. Can soundproofing techniques be used to further reduce sound between two rooms?

Yes, soundproofing techniques such as adding insulation in the walls, installing soundproofing panels or foam, and using sound-dampening materials can help to further reduce sound between two rooms. However, these methods may require professional installation and can be costly.