Archiving media is an important subject. from printed parchment to microfiches, to film reels and hard drives, where data is located in the future is an extremely important topic today as our data usage is unfathomable. According to IBM, "Every day, we create 2.5 quintillion bytes of data — so much that 90% of the data in the world today has been created in the last two years alone". Thinking about this too much is dizzying. So let's go back to a simpler time when "data" was stored stored on exclusively physical media. In particular, 3-dimensional carriers like wax cylinders and vinyl records. These types of recordings are subject to erosion, dirt, and breakage. Once they break, the audio is gone. It would be important to move the sounds from these records onto something more stable and less susceptible to further damage and decay. Why not just play them back and record them onto a digital medium? That would be a fine solution, except that for the older recordings, even playing them back could be too much strain on the media. You would literally be damaging the recording as you played it back. There is an effort called IRENE which is short for the less catchy, *Image, Reconstruct, Erase Noise, Etc. (etc used in an acronym?). It's essentially a 3-dimensional scanner specifically designed to scan the surface of a record or wax cylinder. From these scans, the audio is re-created digitally where it can be safely played back, restored, and cleaned up. As necessary, the audio can also be reconstructed like an old, torn photograph. Take, for example, and cracked or broken record. No record player could play it, but this scanner could scan it, and the sound stitched seamlessly back together with software.
An example of some audio that has been preserved. You can hear alexander graham bell speaking.
Here is a slightly improved version after it's been filtered. But remember, it's not the improved filtering that's important here. it's having the recording at all.
Similar techniques were used to extract the audio from scott's first recordings onto sooted paper **see post on first sound recordings***
A nice TV special about this and the first recordings
For additional (very technical) reading: