So a few weeks ago I picked up that Tektronix XY display, for actually free. So I thought I would
do something fun with it. So you have that, the oscilloscope and I brought out some microphones
and a flute. So you guess what we are going to do: some oscilloscope music. And I also
have some my generators over there. So we are going to have fun with music and oscilloscopes
in a good old analog fashion. Before I begin the show, let me turn down the lights a little bit,
so we can see the scopes better, and turn on the sound. So as you guessed it,
I have one channel that's on the right side and and does the horizontal, actually that's
the right side, and the other one that does the vertical. So they are in XY over
here and they are in regular fashion on the two traces of my oscilloscope. And then so,
if you put the two of them together you get this beautiful sort of displays over here.
Hello! So that's basically stereo sound and that wouldn't be that much fun, but it's a lot
more fun when you start to sing to it. Oooooh. And even more fun when you pick up the flute.
And of course the nicer to sound I make the nicer the figure, so I should use that to get better,
obviously I'm a hack at it. Okay, for the next bit of fun we're going to use oscillators,
so we have one on the vertical channel, and one on the horizontal channel. That's those
two. This one is an audio distortion analyzer, the one that tells you how good your amp is.
And this one is a function generator. So right now it's a thousand point two Hertz.
It does a big circle. Okay so they are in tune, which actually tells me that they
are not calibrated correctly because one shows 1000 and the other one 995,
and they are obviously in tune here. But what we can do is vary
one versus the other. This one on the right, let's see we can do this.
Oh.
And you get these figures here which are called Lissajou pictures,
and this is a nice one, when there are nice musical notes this when they are in sync.
OK,
here's a fifth musical terms, that's 2/3.
Two and three , so that makes a nice tone.
This is an octave right here.
You get it, it's very pretty. Next of course there is more fun to be had when
you connect this to a computer and this is from a Dutch [Austrian in fact] artist
that got famous with that video on YouTube with this sound file. He started by making
a mushrooms. Today I'm going to show you how to draw mushrooms on an oscilloscope
with sound. We're gonna use our left audio channel for horizontal deflection
and our right audio channel for vertical deflection. Now first we need a sine wave
on our horizontal deflection channel and a cosine wave on our vertical deflection
channel. Together they add up to a beautiful circle. We can alter its
size and shape by increasing or decreasing the volume of both channels. Now we add
a sawtooth waveform to the right channel. Our circle or ellipse turns into a spiral.
To get the spiral into the shape of a mushroom we need to multiply
our left channel with a sine wave of the same frequency as the sawtooth.
But we're only gonna use the sine's last quarter.
Of course we want our mushroom to move,
just like in real life. Right you are going to see the mushroom on this channel.
That's why we now add another sawtooth,
multiplied with a cosine wave of a slightly different frequency to our left channel.
We can increase the number of mushrooms by dividing
the cosines frequency by two, or even by three.
By randomly adding square waves we get even more mushrooms.
In fact we can plant an entire field. So you get it, so the guy got famous on YouTube for
that one. And he actually put a Kickstarter and decided to make an album of oscilloscope songs,
if he was funded. And funded it did and he totally outdid
himself. This is what came out of it after he got a little bit of funding.
We need to turn the lights off for that one. It's called "shrooms".
I think it's fabulous.
Name of the guy is Jerobeam Fenderson.
And you can buy the album and even have a vinyl of it.
And he'll give you the video if you don't have oscilloscope like I do.
It gets totally psychedelic after that.
All right guys that was fantastic. Oh R2-D2 sounds. Where are they coming from. OK,
so give a hand to a Tek 603 and a Tek 7854 and the
incredible Jerobeam Fenderson from Holland [Austria actually]