Covox Speech Thing SPU

Hardware entity

An extremely primitive & cheap dongle that plugged into a parallel port to provide 8-bit DAC digital sound output that was superior to the PC speaker.


The first video game about Covox Speech Thing SPU was released in 1989.

Electronic Arts and Knowledge Adventure has published most of these games

Despite being composed of fewer than 25 cheap parts (mainly 18 resistors) available at any electronics store, it retailed between $70-$80 to be slightly cheaper than decent sound cards available at the time.

Sound had to be completely generated through the CPU so quality was limited to CPU speed and how much bandwidth the developer wanted to spend on sound and/or music. Duke3D used up to 44KHz and 8 voices of music, sound, and speech.

Many versions, including the original, has a pass-through port so a printer and such could be plugged-in without removing it.

The idea was directly cloned and/or improved upon by other companies who sold their versions for as little as $9.99. Disney Sound Source was once such improved device for $14.

It was not that difficult for a PC user to build their own clone.

A good purpose of this device was for laptops that had no sound hardware except a speaker.