fun with the oscilloscope

here are some videos of audio out of the computer plugged directly into the oscilloscope. red/right is plugged into x and black/left is plugged into y (backwards, i know). the links are either "no math" (just x and y shown) or "x-y" (x and y along with a third line that is x-y). the sound isn't very good, but it's better than nothing...
  1. the gambler, kenny rogers (x-y)
  2. james bond theme (x-y) (no math)
  3. killing machine, my regrets (90 sec, no math)
  4. eye of the tiger, survivor (x-y)
  5. paradise city, guns n roses (x-y) (90 sec, no math)
  6. welcome to the jungle, guns n roses (90sec, no math)
  7. everybody knows, leonard cohen (x-y)
  8. fight for you right, beastie boys (x-y)

i figured out how to grab screen shots, so here are a few pictures too...
  1. x at 120V A/C and y at 120V A/C with x-y
  2. x at 120V A/C and y at 60V A/C with x-y (60V via a diode)
  3. x at 120V A/C and y at ~1.8V DC with a cap (it's a rectifier with a capacitive filter)

the lissajous curve: to do this i plugged the audio cable into the oscilloscope (black left, red right), set it to x-y mode, set the x and y voltage to 200mv and time to 250 kSa. here are the sound files played (created with audacity) and a few pictures to go with them:
  1. the 1:2 (left 440 Hz, right 880 Hz) and the mp3
  2. the reverse (2:1, left 880 Hz, right 440 Hz) and the mp3
  3. the 3:4 (left 1320 Hz, right 1760 Hz) and the mp3
  4. the reverse (left 1760, right 1320) and the mp3
  5. a circle (left 440.2, right 440.2 time shifted) and the mp3

problems, questions? e-mail olmstead at
this may have been useful...
last major update: 9/6/2016