Let’s say there’s a baby’s room at one end of the hall and the parents’ room at the other. Each room has a door, but in this scenario, only one door will be closed, and the other will be open.
If the baby starts crying, does it make any difference which door is closed, in terms of the parents being able to hear, or is the volume just the same in either case when it reaches the parents’ ears?
​
Edit: To be super clear, this is hypothetical, and if I had a baby, I’d want to hear the crying if it was happening 🙂
I have a door at the bottom of a stairway that opens to a shared hall with my neighbor, and when she’s jingling her keys and unlocking her door, it sounds like she’s right in my apartment. So I was wondering how well she can hear me at that time. Sounds like, unless there’s something one-way about the acoustics in my stairwell, I should assume she can hear me at that time about as well as I can hear her.
In: 18
Baby’s door closed would be quieter. When you muffle the source sound doesn’t travel as far.
As a person living in your hypothetical situation. It doesn’t matter, they will up the volume until you are awake and coming too them. Doors open or closed, they be loud.
In a straight line it wouldn’t matter, but in a house it would be quieter to close the door closer to the baby if both doors are the same.
A noise has a starting volume. It gets weaker over time. Objects in the way will also make it weaker. Regardless of the positioning of the object, the noice still has to both travel a certain distance and pass through the object. So, it wouldn’t matter.
However, in a house, the sound will expand out and start to bounce off walls, cause echos , etc. It will have new paths through walls, door gaps, vents, an so on. The quietest solution, because you arent in a tunnel, would be to weaken it at the source instead of the end point.
That’s a good question with not a fixed answer.
With an ideal physics’ book on the hand and in an ideal world….. it’s more likely better to close the parent’s door as the door capacity to reduce the sound IS a fixed percentage of the incoming “energy” and when the sound reach the parents door it has less “energy” due to distance (same as an earbud inside your ear is loud and as you pop out at a distance you can’t barely hear it). On the contrary the way we perceive volume IS NOT by a fixed percentage of incoming energy (the so called decibels) so it’s better to dim the lower “energy” at the parent’s door as it will have a bigger impact on our hearing perception.
Although this is not the last answer…
Actually it’s compromise problem of maths. We have the sound that looses “energy” with distance with certain mathematical formula and we also have our hearing perception that work with a completely different mathematical formula. So the optimal solution may depends on the distance of the doors, the characteristics of the door and the “energy” coming out from the baby’s mouth. Different set up will bring different solutions.
Although this is not the last answer…
The described above is the ideal problem, in a real scenario there is reverberation that amplify the sound on the hall before parents door, that’s why sometimes close the baby’s door is a better option, but there are so many other factors such as geometry of the house, non ideal materials, absorption of the walls… an those factors can play a big role on changing the solution, so its quite a complex problem that needs either complex calculus and test or simulations…
.
^(If someone wonders, the sounds looses intensity as inverse quadratic with distante and our sound perception follow a logarithmic pattern with sound intensity)
In each case, let’s say the door absorbs 10 decibel, and the corridor 10, doesn’t matter the sequence you always lose 20 decibel.
By closing baby door however, you increase the area of the house where you benefit from the door noise reduction, as now you can walk to the kitchen or toilet and still be screened at least by 10 decibel of the baby’s door.
This is assuming math checks out IRL. In don’t think real materials do screen 10 decibel whatever is the source or the distance you put them. Maybe a particular door type is more effective when close to the child or is better at distance from the child.
By the way, decibel is a logarithmic scale, purpose of it is to cancel out vs the inverse quadratic sound behavior. This way we just need simple math. You don’t care to calculate power, a 10 decibel barrier does alway reduce the sound by 10 decibel.
Latest Answers