Early Bell recordings live again (kind of) • The Register

The Lawrence Berkeley National Laboratories says it has reconstructed sounds recorded in Alexander Graham Bell’s laboratory in the late 19th century.
Rather than trying to construct a machine to play the recordings, stored at the Smithsonian Institute, the researchers have recovered what has to be described as muddy and difficult-to-understand audio using a 3D optical scanning technique.
According to Physorg.com, the LBNL scientists worked with digital capture specialists and museum curators to capture the samples using a system called IRENE/3D. This takes high-resolution images of the disks, which are then processed to minimize the noise caused by damage and deterioration in the century and a quarter since the recordings were made.

The IRENE/3D system then mimics a stylus moving across the disk to play back the recorded voices – without actually touching the disks.