Speech Plus voice synthesiser circuit board. Deactivated by the removal of several microchips.

This is one of Stephen Hawking's original speech synthesizer boards, which outputs his distinctive voice. It is a hardware device built in the 1980s, and despite decades of progress in speech reproduction software, Hawking continued to prefer the output of these original boards. He posessed several of them, but as they had stopped being produced decades earlier, they became very valued artifacts.

Through the last decade of Hawking's life, there were attempts to reproduce either by reverse engineering the hardware, by its computer emulation, or the reconstruction of its voice by software and artificial intelligence. These efforts were still ongoing by the end of Hawking's life, so original synthesizer boards such as this one continued to be part of Hawking's everyday life. They were housed in cases that would be attached to the back of his wheelchairs; the wheelchairs had modern computers and communication interfaces, but these all needed to be connected back to the 1980s synthesizer such as the one you see here.

As with other similar objects given to the Science Museum, this synthesizer has been inactivated by the removal of several microchips, so that Hawking's voice cannot be reproduced by it anymore.