Lichtenberg figures

In my 3^rd Bridge Helix article on furious.com I briefly mentioned the harmonic forces of tubes in tube amplifiers, comparing them with Tesla’s Plasma lamp. This following text is about vacuum tube compression and tape compression, not really about tube overdrive, in case you might think. The phenomenon however becomes more apparent at a driven amplifier sound or when recording in the red.

For a long time I was searching for information about the typical visual patterns of a lightnings and I just found it. They are called a Lichtenberg figures. The patterns are mainly known from lightnings, but also present at other places in nature. For instance on the surface of the Norwegian coast viewed from above, snowflakes and other crystal dendrites as well as many living organisms or our own blood distribution network, which in those cases are called the result of diffusion-limited aggregation. The Lichtenberg figures are based on fractals. The fractals on their part are based on the harmonic series as Ray Tomes points out very clearly in his 4 piece YouTube serie How to Make a Universe (www.youtube.com/watch?v=c8Hgaa6wlNs). I can’t exactly follow every step he makes, but at least the calculations he summarizes are not incorrect.

Argued from the opposed direction, there is a connection of the harmonic tone blending characteristics of vacuum tubes and this phenomenon. In vacuum tubes in guitar amps electrons, representing the sound of the electric guitar, clit together, leading to a distorted result but in a good way, because the sound becomes more pleasant for our ears. We like merged sound with simple ratio relations more than complex sound with unlogical ratio’s. I’ve played for years on heavily driven transistor amps and noticed random chords with non-matching notes don’t sound very nice, however if you play abrasive chords on a driven tube amp a somewhat sweet jazzy sound appears in the field of noise. Old vacuum tubes are known for their more pleasant sound. The tubes have leaked very slightly and are not as vacuum anymore as in the beginning, causing more tree like structures in the electron beams, causing a more harmonic blended sound.

In the interview I did with Sophie Pécaud I explained her this on mail by showing 2 pictures. One is the visualisation of white noise made in photoshop and one is the result of a painting technique I had developed in the past and which represents the Lichtenberg figures. I had accidentally discovered how to create this effect with a frottage technique with acrylic paint. Transistors don’t have space for the electrons to blend and don’t translate the actual signal very much. The random notes stay random, causing an annoying sound. The tubes however blend it and shape it to a natural pattern we like to hear.

For sound recording a similar thing happens. Magnetic iron parts tend to cluster together like a pointy crystal structure on a magnet. On the tape this also happens in a 2D version of the crystal structures. Digital recording registrates white noise like the upper half of the pic. Magnetic tape blends it to the moss like patterns. Maybe not so clearly as shown in the drawing, but on microtonal level it does leading to a more easy listening sound. Recording in the red emphasizes this harmonic blending effect. Lo-fi is for that reason not particularly bad sounding. I actually like the blurry effect of for instance the first The Thermals record a lot, where this happened.

Additionally I found on www.capturedlightning.com/frames/lichtenbergs.html not only the tree like patterns that are called positive Lichtenberg figures, but also imploding pictures of negative Lichtenberg figures, making it for myself more easier to imagine sound is coming together when put through a driven tube or recorded in the red on a tape.

From W.W. Lewis, "The Protection of Transmission Systems Against Lightning", John Wiley & Sons, 1950

Viewed from the anode the beams of electrons function like black holes and cluster groups of nearly equal frequencies to a more densed equal harmonic tonal pattern (2^nd black & white pic above illustrates the black hole like shape, next to the picture a NASA illustration of a Black Hole.).

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