In my novel, a character makes the claim that sound can be recorded by the panels in a door. The door panel vibrates with sound, according to him, and those vibrations are recorded analogically, very much in the way sound can be recorded in an emulsion by rearranging metal particles embedded in that emulsion using an electromagnet, or on a wax disk via a vibrating needle.

According to him, the panels in a door - even a very old door that has been floating in water for some time - contain the record of every sound that has been made in a room since the door was first hung there: Since wood is a living material that retains flexibility over very long periods and has a "memory," the wooden panel retains, according to him, the memory of its displacement in response to the sounds it has "heard." He refers to this as "kradasmolignic memory." He is looking for someone who can devise a way of reading that recorded information. There would be many potential uses. He would, for example, be able to recover performances by famous singers of the past currently thought to be lost forever, or conversations between historical figures. Fortunes might be made.

How would the fibers of the wood in a door panel actually record sound, if that were possible? And how could that information be read?

Response to Juraj:

Wood in the door is not living material anymore, it was processed, dried and treated. Plus, most doors nowaday are made from particle board and plastic foil surface.

The door in question is not from nowadays. And as for wood not being a living material, I can't agree. Have you ever cut a 150-year-old piece of pine and had sap ooze out? I have. I won't claim that the wood in the door continues to "grow," but that would be a possible way to add the linear dimension Gilad M refers to.

I'd also like to add that I don't understand why people are using terms like "comic-book science" and "potential scam." As I understand it, the aim of this site is to help people who "construct imaginary worlds and settings." I'm here to see if anyone has ideas of how the idea can be given plausibility based on their knowledge of real science, not to try to claim it is real science. Or have I misunderstood the purpose of this site?

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    $\begingroup$ Welcome to worldbuilding. First clarification question: your question has nothing to do with time travel, why have you used that tag? Second question: what are you asking here? If you decide that in your world objects have memories of all the sound they were exposed to, so be it. We don't deal with story development, we deal with worldbuilding problems, What is yours? Please take the tour and visit the help center to better understand our community. $\endgroup$
    – L.Dutch
    Aug 12, 2019 at 7:35
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    $\begingroup$ Is "kradasmolignic memory" a real thing or is it something you made up? This concept of recorded sound in door panels has all the hallmarks of a potential scam. $\endgroup$
    – a4android
    Aug 12, 2019 at 8:47
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    $\begingroup$ This sounds like comic book science. As in, something that doesn't work in the real world. Even if that's how it worked, then when the objects record every sound then a 10 year old door frame won't have one 10 year old recording but all 10 years into the same space. Imagine overwriting the same tape over and over but instead of replacing the information, you just add another recording that plays alongside it. Very soon you'd have a useless cacophony at best. $\endgroup$
    – VLAZ
    Aug 12, 2019 at 9:23
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    $\begingroup$ With that aside, sound is a vibration, it moves. Staying in one place (as a recording) requires transforming it into something else. Our brains store it the same way we store other information. We have learned ways to write down sound and create new sounds that match it in forms of musical notes and other symbols. We can also transform sound into magnetically charged particles to write on tape. Or burn little notches in plastic as a CD. And so on and so forth. We don't store sound as it appears naturally because it's not possible. $\endgroup$
    – VLAZ
    Aug 12, 2019 at 9:23
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    $\begingroup$ This is a perfectly valid worldbuilding query as it, surprise of surprises, actually deals with an in-world system (how a physical phenomenon works). "Comic book science" it may be, but it's our job to sort out ways to explain it. Yes, this query is "opinion based", but it is certainly within the scope of our forum. $\endgroup$
    – elemtilas
    Aug 12, 2019 at 14:42

3 Answers 3


Sadly, no

I had a long, rambling explanation that delved into information theory and thermal equilibrium, but here's a simpler way to see why. There are 2 possible answers to the question, "does wood retain long-term deformations in response to sound?"

  • If no, then the information in the sound disperses quickly and can't be recovered.
  • If yes, then any sound will overwrite previous deformations like recording over a CD.

I haven't heard any evidence of wood having "memory" like you mentioned, but I think this argument suffices to show that even if that exists, it wouldn't be enough to read back sound. If any sound information can be recovered, it will be the most recent sound, likely a gust of wind against the door frame.

Recording doesn't just require a plastic material that can hold the information (like a record), but also a mechanism that makes sure that the deformations are stored in sequence (like a needle and turning table).


Most likely it is impossible, however some time ago -scientists managed to recover voices of the ancient Potters from the microscopic grooves in the clay-. Edit: They didn't, but it should be within the realm of possibility.

So here's an unlikely scenario:

Somebody done a lousy job and managed to paint the pins of the door hinges, before setting the doors.

The hinges themselves have a sharp imperfection on the inside at the very top, which would work as an old-style recording needle.

When the doors are moved, and there is a LOUD noise present, the panel would vibrate, scoring a mechanical recording in the layer of paint on the pin. At the same time a layer of paint at the bottom of the pin gets stripped away and the whole door sags a bit, thereby protecting the "recording".

So in essence, however unlikely, this is the only way a door panel could make and preserve a recording of sorts. Of course the whole recording would last maybe a couple of seconds, and would probably require a laser scanner and a supercomputer to recover (not to mention somebody would have to identify it first).

  • $\begingroup$ "Scientists managed to recover voices of the ancient Potters from the microscopic grooves in the clay:" citation needed. I have once upon a time read a science-fiction story based on this conceit, but I would be exeedingly happy to learn that it has really been done. $\endgroup$
    – AlexP
    Aug 18, 2019 at 19:06
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    $\begingroup$ It seems that I've fallen for an April fools joke, and the best so far was the sound of the potter's wheel itself. My world just became a less magical place, but thanks for fact checking me. $\endgroup$
    – Lumberjack
    Aug 18, 2019 at 19:37

Yes, and No

Yes, technically

Theoretically, with good enough instruments you could get the sound that caused the deformation in material. Put a plastic sheet in ideal conditions, produce a sound in the sound proof room it is in, and then analyze it.

No, because of saving

However, you are right about something else. The door does contain the record of every sound that has been made in a room since the door was first hung there. However, these are all stored on top of each other. Imagine splitting the complete works of Shakespeare up into millisecond long clips and putting all that audio on top of each other. Can you get from that The Merchant of Venice? There is so much signal that it is hard to make out which signals are which.

No, because of error.

If this is a door, then people probably touch it, that has more of a deformation effect than sound. slamming a door makes even more deformation. Cracks for naturally and randomly. If this door has been in water then there is also water damage that makes it hard to read. The noise to signal ratio is off the charts, so you can't read it.


Imagine taking a magnetic tape, and saving one thousand times its capacity on it. Also, all a 1 does is flip the bit and a 0 makes no change. Also pass a high power magnet over every time you save it. How readable do you think any of the data will be?


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