digital equipment corporation · maynard, massachusetts
The classic sound programs for the PDP-8 worked by executing instructions which caused electromagnetic interference (EMI) changes which when picked up by the AM radio produced sound. One program executed an instruction which caused a large EMI spike a the correct rate to generate the tones, another switched execution between two different core addresses.

The one I have reads notes from a file and can play chords. The quality varies the radio used, location, where tuned, and various other things. I think it can be better than the sample I have but I need to play more.

Some archive of songs and source are at ftp://metalab.unc.edu/pub/academic/computer-science/history/pdp-8/music/

More at ftp://ftp.dbit.com/pub/pdp8/nickel/music/

I also have an RK05 image of a DEC diagnostic pack with a music program and music files at ftp://ftp.pdp8online.com/images/os8/ file diag-games-kermit.rk05.

Samples of Beethoven 5th. Starts with the beginning of the song then I stopped the program and started the next song (the 5th third) loading. The strange sounds are the EMI from the computer while reading and processing a file from the RK05 drive. The .wav file is closest to the original sound but the others sound better with some of the high frequency removed.
As a .wav file (530K) (Should work on windows systems)
As a .mp3 file (191K) You may need to right click to download and use a special MP3 player.
As a .au file (382K) (Sun, unix etc)

More to come later. More samples, hopefully better, more information. Possibly live playing from my machine. Email me suggestions below

Feel free to contact me, David Gesswein djg@pdp8online.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with.  I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation. 

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