UPIC Impressions of Paris

UPIC Impressions of Paris

This is my first UPIC piece at CCMIX. UPIC (plus bonne version française) is a graphical, glissando-oriented system designed by Xenakis. This piece uses all sine tones and all glissandos are straight lines (no vibrato)

This piece contains extremely low frequencies that may be difficult to hear on some speakers. The sounds are inspired by the surprising, different and wonderful mechanical noises made by the appliances in my kitchen here.


5 thoughts on “UPIC Impressions of Paris

  1. Aaron

    Hey Celeste. I really like this first UPIC piece. It reminds me of some of your other stuff with filter banks. I am interested in UPIC, from a distance I suppose. is the graphic surface an x/y axis that you can then assign synthesizer variables to? Telll me more, or point me to a good sight. I think the sounds you produced are very organic and they sound as if they don’t have a static harmonic series. If this was Xenakis’ intention then sounds like a success.

    I will say, though, that there is a somewhat antiquated sound to the piece you made. Like it could have been made sometime in the 70’s and no one would know the difference. Is the Interface an old one, or does it have up-to-date technology involved. Forgive my ignorance. Can’t wait to hear more.

  2. Les Post author

    Thank you :)

    UPIC is a graphical system where there exist scores called “pages.” The pages are made of line drawings where x axis represents pitch and the y axis represents time. Lines drawn in this system are called arcs. Every arc has an assigned waveform, a channel, a maximum amplitude and an envelope. FM modulation is possible, however, the amplitude of the signal arc is also the amplitude of the signal for modulation, which makes some nice complex timbres very difficult to obtain. AM modulation can be faked via complex envelopes. The waveforms only have a certain number of samples, but within this constraint, they can be drawn graphically and can even be made up of “wave forms sampled from real sounds, however, because of the sample rate of the waveform, long, complicated “samples” get aliased.

    The interesting thing about UPIC, aside form the graphical element, is a concept of inexact cut and paste. You select things to copy and then, with the mouse, describe the rectangle that you would like to paste into. The result is then scaled to fit within the rectangle you described. The chances of getting something exactly are very minimal.

    The reason UPIC pieces tend to sound antiquated is because of the limitations of additive synthesis and the lack of filtering. Also, my piece only uses sine waves instead of more harmonically complicated waveforms. UPIC is not a new system. The version at school has dedicated UPIC sound hardware. There’s an ancient PC-only version. If you’re interested in the ideas behind UPIC, metasynth gives a few of the pieces of it. You could fake a lot of the rest in SuperCollider by using wavetables to describe the waveforms, the envelopes and the arcs. Then you would need to track the start point of your arcs (on the x & y axis) and the horizontal and vertical scaling. I haven’t decided if this is a project worth pursuing. However, the glissandi are nice and the graphical score does make it easier to keep track of a lot of additive waves.

  3. Thomas Baudel

    Of interest to anyone on this page: a java application that implements a good deal of the original UPIC.

    There are still some work to be done to allow greater power of expression.

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