Graphic Samples

Have you ever listened to a module with a player that shows the graphic view of the waveforms played? Normally they don't show interesting figures, but wouldn't it be possible to make instruments that show interesting things, like texts, or little animations? And - how would that sound?

Still Pictures

Normal Samples exist of an array of numbers which tell the D/A-converter what voltage to output at a moment in time. The higher the number, the higher the output voltage. And that is exactly what is displayed in waveform displays. (Picture: From numbers to waveform)

The problem is, that in one position in time there can only be displayed one voltage (in a normal function there is only one f(t) per t), so pictures like a Smiley for example aren't possible, because in a Smiley there are t-coordinates with four values above each other (four f(t) at one t!) Therefore the Smiley is splitted to four functions f1, f2, f3, f4: (Picture: From Smiley to f1..f4)

Now we can use the fact that the width of the waveform display is finite and the displaying of the function starts at the left border of the display area again after some time. Now it is possible to put the four functions f1(t), f2(t), f3(t) and f4(t) (that are needed to produce a smiley) after each other, and, if you play the sample at the correct pitch, you can reconstruct the picture in the sample display: (Picture: From f1..f4 to Smiley)

Here is an example Smiley for you to download: smiley_xi.zip (contains smiley.xi, less than 1kB)

Of course, also other graphics are possible, like this nice writing "Yaka": yaka_xi.zip (contains yaka.xi, less than 1kB)

These samples are handdrawn in Triton's FastTracker2, and saved as FT2 .xi-instruments. Looping the samples is essential. If you want to use the samples in another tracker, use the following files: smiley_rw.zip (contains smiley.smp, less than 1kB) , yaka_rw.zip (contains yaka.smp, less than 1kB) They contain the raw sample data. Again, it is necessary to loop the samples, or you won't hear or see anything. Try various pitches until you see the correct picture.

Animations

It is possible to make still pictures in samples, and it should also be possible to do whole animations. For this, one simply puts the frames one after another in the sample file. I wrote a little program that calculates a rotating square. Here is the result: sqare_xi.zip (contains square.xi, 1.2 kB) , sqare_rw.zip (contains square.smp, 2.2 kB) This one even sounds nice! Again, i put the upper/lower border of the square in each frame after each other: (Picture: From square to sample)

I think much more is possible with the technique of graphic samples, and last not least one gets new interesting sounds. Oh, another interesting fact for your own sound creation: if you use pictures that are 128, 256, 512 etc. sample values in width, you will get "correctly pitched" samples - at least i think so. The frames in the rotating square are 256 bytes in width each, and the pitch fits perfectly with the other sampes i use.

Yaka/Xography

Xography Home Page created by Yaka/Xography (Daniel Berger) / daniel.berger@tuebingen.mpg.de