Slime Mould

While practicing archery in the woods this year, I’ve spotted some funny-looking fungus-type things that I’ve since learned are slime moulds. I was aware of slime mould as a weird life form already, having read research into using them for solving mazes and analogue computing applications, but hadn’t seen any in real life until recently. In June I shared a photo on Twitter of a “weird orange fungus” that had caught my eye in the woods (it was almost glowing orange – the picture doesn’t capture its intensity). Replying to that tweet, C. Reider identified it as Wolf’s Milk slime mould (Lycogala epidendrum).

That same weekend, I also saw this thing, which I later identified as Fuligo septica, also known as Scrambled Egg or Dog’s Vomit slime mould. Like other species, it has a resistance to high levels of metals, but this one is unique in its resistance to zinc – a property related to its yellow pigment. In this photo you can see the trail of slime that evidences its movement.

On the tree of life, slime moulds are classified as Protists, which means they are neither animal, plant or fungi. There are three types of slime mould: plasmodial, cellular, and amoeboid.

Plasmodial slime moulds are the most likely to be seen. These include Physarum polycephalum (the yellow one that solves mazes) and Fuligo septica (pictured above). They begin life as individual cells that join to form a plasmodium – a single-celled but multi-nuclear blob. The photo below shows Fuligo septica at an earlier stage in its life-cycle, when the plasmodium has transformed to a spongy aethalium, but before it releases spores, when it hardens and darkens.

Cellular slime moulds spend most of their life as a single-celled organism, like amoeba. But if food gets scarce, they emit chemicals that allow them to find each other and they join together into a multi-celled organism that can sense and move towards food. Individuals also converge in order to reproduce, in which case the cells differentiate in function, forming stems with fruiting bodies that release spores, like mushrooms.

Amoeboid slime moulds share some characteristics with both the plasmodial and cellular groups and are more difficult to classify.

The Forestry Commission, which manages these woods, have marked up some trees with fluorescent spray paint, and it’s easy to mistake a slime mould for a patch of paint among the pine needles on the forest floor. For example, here’s a Physarum polycephalus, which I spotted for the first time a couple of weeks ago. Closer inspection reveals the veiny network of the plasmodium.

This bright orange slime mould is Leocarpus fragilis. Up close, you can see that it’s made of lots of small blobs, each attached with a thread. These are the fruiting bodies on stalks that will release spores.

Last weekend, I found two white slime moulds. The first looks like small blobs made of individual fruiting bodies, like white caviar. I haven’t yet been able to identify this species.

The other one is probably Ceratiomyxa fruticulosa. At a glance, from head height, it just looks like some normal white mould on a rotting log. But looking closer you can see that it’s made of small translucent star-shaped fruiting bodies, a bit like fingers made of jelly.

[Addendum, 18/09/2022] This weekend going round the archery course, there weren’t as many slime moulds or fungi because it’s been drier recently. But I saw the same patch of Physarum polycephalus slime mould that has now turned from yellow plasmodium to black fruiting bodies (the ‘many heads’ referred to in the name polycephalus):

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Sean on Autechre’s Reverb

Yesterday, Sean Booth of Autechre did an ‘ask me anything’ stream on I watched the last half live, and today I caught up with some of the bits I’d missed at the start. I was pleased to find that he’d answered a question about Autechre’s use of reverb. Here’s my transcription of that section (in the first video, from 00:38:50 to 00:43:58

[Chat 20:49]
travx259r: your use of reverb has always been inspiring. any comment on your approach designing reverb in songs?

[Video 00:38:50]
Sean: Yeah, I mean, I sort of… A lot of my reverb… Oh wow! Look at this bug. Oh, it’s flown off. Yeah a lot of my reverb is tuned. I love eighties reverb. You could always hear a good producer in the eighties cos he would not just arbitrarily shove the reverb on something, it’d be somehow in tune with the other elements in the track. You get it more in hip hop than anywhere else. You get it where somebody’s laid the beat down and the reverb’s in the mix already but then the MC’s come in, and the MC’s got the reverb in his cans and somehow it’s informing the pitch of what he’s doing. He’s sort of in tune with the whole tuning of the track, and I dunno how much people are aware of when they do this stuff but I just think that they’d do it anyway, they’d do it naturally, right, so they just find the tuning. It’s a bit like if you write a beat on a 606 and then you go to write a 202 pattern over it, you’re gonna write something that’s in tune with the snares and the hats. For it to sound good, you don’t just arbitrarily… Cos I’ve never done that, I’ve never thought “Oh, these are rhythm elements and their pitch is unimportant, and these are the song-writing…” You know, I can’t think like that at all. To me, the whole thing is music. And I think good producers – this is what makes good techno producers – a lot of the time is they’ve just got a knack for picking up that natural tuning. And it’s the same way you might pick up the natural… the types of rhythm that work at different tempos, for example. You know what I mean? And you’ll have the types of tunings that work with certain drum machines, if they’re not the sort of drum machine that you can tune. I mean, you can tune a 606 I guess, if you get the back off, but a lot of people don’t.

I think with reverb, the sort of eighties reverbs a lot of the time they had a very definite tuning. They had a sound that some people described as metallic and inharmonic, but you always got a sense that there was some sort of key coming off it, sort of a HHHEEE [breath sound] or a HHHUUU, you know, different notes. And so, um, I quite often use very simple reverb topology, but, like, I have a hand in influencing the tuning of it, so, depending on what the chords and the melody are doing, the reverb’s tuning will be different and it’ll change over time. That’s the key thing, I think, if you want to get that [American accent:] ‘Autechre reverb sound’. Again, I’m not telling you how to do it that way, that’s just what I like, I just like those shitty reverbs from the eighties, the MIDIVerb and the Quadraverb. The topologies are seriously fucking useful and very very low on your CPU and give you “THAT” sound, if it’s that sound you’re after. In my case it’s just experience of having had those machines for years and just loving ’em because I’ve had them for years, you know what I mean? I’ve just grown to love them the way that you love your dog or something, so, you know, it’s like that. And I’m not saying they’re the best type of reverbs. They’re definitely not. You know, there are some modern convolution reverb that are just beautiful. That thing Zynaptiq did, whatever it’s called, that’s a seriously gorgeous sounding thing. But it is what it is, right? It does what it does.

Quite often I’ll use other techniques that aren’t reverb at all, so I’ll have, like, lots and lots of delay lines and all-passes but not set up in a normal reverb topology, and just explore different topologies because there’s just so many ways you can connect all-passes and delays and combs that you can make anything, almost any of those combinations of those things is going to be a bit reverb-like. But you might find that it might make more interesting tones or sounds than you would get from a reverb that’s designed to be an all-purpose reverb, if you know what I mean. Quite often the smaller, shitter topologies can sound more interesting. There are no rules with reverb. When you start researching different types of reverb design over the years you realise that there are no hard and fast rules. Everybody’s just doing different shit. And some of the more effective topologies aren’t necessarily the most complex. You know, getting complex results doesn’t rely on building a complex machine. This is a really important thing to note. Sometimes the most simple machines can give the most complex results and the most pleasing results. You might not even be after complexity. It’s something I like, but not everyone does. Just experiment, basically. But that’s just general advice. I’d say always experiment.

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Blood Music Birthday

Last night was the Blood Music Birthday event at Iklectik, London. This was a gig to celebrate Simon Pomery’s recent birthday. The line-up was:

  • UAN – minimal, morphing repetitive beats
  • En Creux – no-input mixing
  • me – video + audio piece
  • S McEvoy – piece based on tinnitus sounds
  • Blood Music – ‘For the Vagus Nerve’, spoken word, processed guitar
  • Roberto Crippa – synth-based rhythmic textures
  • Tom Mudd – physical modelling synthesis
  • Blood Music with Roberto Crippa – improvised drums and synth

Travelling down to London was a bit of an ordeal because of the storm and high winds which meant trains were cancelled. Luckily I got a lift from Tom and Maude who were travelling down from Edinburgh. It was lovely to finally meet face-to-face with everyone and to hear them play live. Iklectik is a nice venue – the sound system was good, the staff were helpful, and there was also a resident cat. Everyone played well and sounded great.

I showed an animation I made with the Fractal Flames algorithm – an old piece with a new soundtrack based on analysis of the video frames. Using Mathematica, I analysed the frames in terms of file size, number of colours, and number of black pixels. I also created derivatives of these datasets, e.g. measures of permutation entropy and the difference between consecutive numbers. Then these datasets were converted to MIDI files and played with Razor VSTi synth. The result is an experiment in synchresis, trying out the extent to which the visuals and the audio inter-relate when there is an arbitrary but formal correspondence between the two and when what we see affects what we hear, and vice versa.

En Creux
Guy Birkin
Blood Music – ‘For the Vagus Nerve’
Roberto Crippa
Tom Mudd
Roberto Crippa + Blood Music
Tom Mudd, Maude, S McEvoy
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Get This: 32 Tracks For Free – A Tribute to Peter Rehberg

The loss of Peter Rehberg prompted the $ pwgen 20 collective to express their grief by making music in his honour. This activity snowballed into a larger collaborative project as more and more artists expressed a desire to contribute. The result is a collection of 32 tracks by friends and fans of Peter including many whose music has been released via [Editions] Mego. The album was released on 22/01/2022, which marked 6 months since we lost Peter. The album is free/name-your-price, but any proceeds are going directly to Editions Mego to cover expenses.

Design by Tina Frank.
Mastered by Russell Haswell.
Promo video by Takashi Aoki.

In addition to designing the album artwork, Tina Frank’s contribution is a video, pliii:

$ pwgen 20 is a collective established by Ian M Fraser and Victor Moragues. The group initially coalesced around the project of making music with pulsar synthesis using Marcin Pietrusewski’s NuPG software. This led to the release of 3 compilation albums: Pulsar.scramble followed by Pulsar.scramble volumes 2 and 3. The Tokinogake collective also contributed to the tribute to Peter Rehberg by making a promo video, and many others contributed, especially C Lavender.

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Choral mix for Tokinogake

I was invited to make a mix for Tokingake radio, so I put together a mix of choral music. It was streamed on 15th January, alongside a mix by alkaloide and sessions by Yaporigami and William Fields. Here’s the track list:

  1. Mike Sammes & The Mike Sammes Singers – Ariel [Trunk Records] 00:00
  2. The Ba-Benzele Pygmies – Song For Rejoicing After Returning From A Hunt (rhythm djoboko) [Ocora] 00:43
  3. Arvo Pärt – Cantate Domino Canticum Novum (Psalm 95) [Naxos] 04:44
  4. J.C. & S. Lubtchansky – Choeur Pachtoun – Pashtun Chorus [Disques Vogue] 08:08
  5. Les Charbonniers De L’Enfer – La Luette En Colère (The Angry Uvula) [Ellipsis Arts] 10:19
  6. Harry Partch – Chorus Of Shadows [Innova Recordings] 12:00
  7. Senyawa – Istana (FRKTL Remix) [Drowned By Locals] 17:04
  8. Nomades Du Niger – Musique Bororo [Ocora] 23:44
  9. Morton Feldman – Chorus And Instruments (II) [CBS Disques] 29:20
  10. Igbo – Grinding Song [Bärenreiter-Musicaphon] 34:24
  11. Mozart – Requiem in D minor (KV626) – Rex tremendae [Philips Classics] 36:56
  12. Hannu Jannes – frog chorus, Australia [Engraved Glass] 38:48
  13. Stephen P. McGreevy – Alberta Auroral Chorus [S. P. McGreevy Productions] 41:28
  14. Chris Watson – No Man’s Land [Touch] 46:16
  15. NoMeansNo – Two Lips Two Lungs And One Tongue [Alternative Tentacles] 52:16
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Last year’s round-up didn’t include anything on the environment or politics; it was difficult to write about it because it was all bad news. Things haven’t changed, and COP26 was a failure. Here’s the latest data on CO2 levels:

My political views have evolved from a mostly eco-socialist position to an increasing interest in anarchism. This started a while ago through reading David Graeber and Noam Chomsky, and has been supported more recently by friends in a Slack group who share thoughts and resources. The Anarchist Library has loads of resources online, including introductory texts by Emma Goldman, Peter Gelderloos, Pëtr Kropotkin and others. Anarchism can be described as the absence of rulers but not the absence of rules; it is anti-government but not anti-governance. With an increasing risk of societal collapse triggered by either the climate crisis or political tensions, or both, it is only pragmatic to learn about how societies can function democratically in the absence of government, and this is precisely what anarchism offers. That kind of organisational knowledge is what Graeber contributed to the Occupy Wall Street movement, as described in an article that’s part of a series published on the first anniversary of his death. Although I’m increasingly disillusioned with the current political system, I’d still be in favour of a green new deal, proportional representation, universal basic income and a 4-day week as a bare minimum of policies required to transition to a more sustainable way of living.

These are some of my favourite things from 2021:

AMKS Live ( Semi-regular transmissions from the SKAM crew and associates. SDEM has put some of his mixes for the stream up on Soundcloud and you can find others on Leisure Complex’s YouTube channel.

Aurora Apolito (Matilde Marcolli) (2020) The Problem of Scale in Anarchism and the Case for Cybernetic Communism (Entangled Internationalism). An essay on how to scale up Anarchist social and economic organisation from the local level to national and global, that goes deep into complexity theory. It starts with some fascinating history on Cybernetic Communism – computerised systems for central planning that never quite took off, including the soviet OGAS programme, 1962–70 and Project Cybersyn in Chile, 1971–73. The essay explains some of the main measures of complexity – Kolmogorov (algorithmic) complexity, Gell-Mann’s effective (intuitive) complexity and Shannon (informational) entropy – as examples of the kind of conceptual building blocks that might be useful for understanding the problem of scale and for developing socio-economic networks based on alternatives to government and Capitalist market systems. Apolito says this is an exercise in ‘Mathematical Science Fiction’: “It is meant to envision the mathematical form of a cybernetic communist infrastructure of computation that would replace the profit optimization mechanism of markets.” On a similar theme, this recent book by Thomas Swann looks interesting: Anarchist Cybernetics: Control and Communication in Radical Politics.

Janet BeatPioneering Knob Twiddler (Trunk). Hitherto unknown gems of early British synthesis.

Can – Live in Stuttgart 1975. Until this, there were no official live albums by Can, due to various technical issues that dogged attempts to release recordings from the soundboard. This album is a cleaned-up version of a bootleg recording made by a fan, Andrew Hall, that had been in circulation for years. It’s a nice document of the band’s live work.

Nuno Canavarro – Plux Quba (Moikai, 1998). It seems like anyone who knows this album is a fan. I didn’t know it until recently. It sounds like The Chemical Brothers sampled/copied the tune from the track ‘Wolfie’ for their ‘Salmon Dance’, and maybe it also influenced I’m Happy, and I’m Singing, and a 1,2,3,4 by Jim O’Rourke, who was responsible for re-releasing it and bringing it to a wider audience.

Stuart Chalmers – Suikinkutsu 水琴窟 (Fractal Meat). Japanese aesthetic approaches to garden water-features applied to a cave in the Yorkshire Dales. In place of traditional bamboo, Chalmers uses pots, pans, bin lids and cake tins to produce sound from the cave’s dripping water.

Among the older albums I played when in need of something comforting is Don Cherry’s Brown Rice (1975). Another is Neneh Cherry’s Raw Like Sushi (1989), especially the song ‘Manchild‘. In a recent article in The Guardian, Cherry explains how she wrote it, and says that when she played it to her dad he said, “Wow, that’s kinda jazz. You’ve got seven chords in the verse!”

The Command All-Stars – Provocative Percussion (Command, 1959). An easy-listening album by a label’s in-house orchestra, Enoch Light and the Light Brigade, designed for testing stereo hi-fi systems. Coincidentally, shortly after I first heard this, it was mentioned in an interview with Donald Fagen as something that he and Walter Becker liked.

The Congos – Heart of the Congos (Black Art, 1977). Written and produced by Lee ‘Scratch’ Perry (RIP). Every track is a belter. I also listened a lot to another Black Ark production, Dr Alimantado – Best Dressed Chicken in Town. I’ll never tire of watching Perry at the controls in his studio in the documentary Roots, Rock, Reggae – bouncing, clapping and smiling while punching the tracks and effects in and out.

Whenever I buy albums in digital format, I scan them for replay gain and dynamic range. Replay gain, which measures average loudness, is useful when playing a mix of tracks from different albums because it minimises volume differences. Dynamic range, which measures the difference between peak and average loudness, is for information only and has no practical use. Looking at this year’s music, there are three things that have the lowest possible dynamic range of 0 dB, so these are the loudest tracks of 2021:

  • a0n0 – Unicorn’s Dream (SUPERPANG)
  • Lauren Sarah Hayes – ‘Kill the Pulsar in Your Head’ (Pulsar.scramble vol. 3, $ pwgen 20)
  • Victor Moragues – Inner Skin (Bandcamp)

The album with the highest DR, at 24 dB, is The Real Sound Of Small Talk by Kevin Drumm, which sounds like it’s made with granular synthesis, comprising a semi-random stream of pulses like water dripping and insectoid chirps.

Lorenzo Kom’boa Ervin – Anarchism and the Black Revolution – The Definitive Edition (Pluto Press). Written in prison, originally self-published, now updated. A critique of ‘white anarchism’ and of racism in capitalism, the police and the criminal justice system.

Mark Fell & Rian Treanor – Last exit to Chickenley (Boomkat Editions). Quite different to anything else by either artist, this is a product of their adjustment to a more cyclic and slower tempo of life in lockdown while caring for their mother/grandmother suffering with dementia. It’s a long-form collage of field recording and music that takes its time to unfold.

Drew Flieder – Attractors. Music based on strange attractors – mathematical representations of the patterns of behaviour towards which chaotic dynamic systems gravitate.

Will Guthrie – People Pleaser Pt.II. Bewildering rhythms made with a mix of programmed and played drums together with samples, synths and effects.

Judith Hamann – Hinterhof (Longform Editions). A bit like Fell & Treanor’s Last Exit to Chickenley, this album represents the experience of living in and listening to a specific location – in this case, a hinterhaus apartment in Berlin. Hamann’s A Coffin Spray (SUPERPANG) is good too, based on cello overtones.

Mohammad Mostafa Heydarian – Songs of Horaman (Radio Khiyaban). Persian music by a Kurdish tanbur player accompanied by a drummer. This was a tip from Marc of Hive Mind Records, whose catalogue is well worth checking out.

The Human League – Dare (Virgin, 1980). I was familiar with the remix version of this album, Love and Dancing (1982), released under the name The League Unlimited Orchestra, but not the original. Perfect pop.

Screenshot from the video of Live at Mandako in Kumamoto

Eiko Ishibashi / Jim O’Rourke – Live at Mandako in Kumamoto (Bandcamp). Beautiful recording of an intimate performance.

Life Without Buildings – Any Other City (Tugboat Records, 2001). An interview with Sue Tompkins in Tone Glow was what alerted me to this album from 20 years ago. I knew of Tompkins from her collaboration with Russell Haswell but hadn’t heard Life Without Buildings. It was interesting to read about her process-based approach to lyrical composition. That interview was published in February, when the UK was in its 3rd national lockdown due to Coronavirus, and so this album lightened up the dark and dismal period of what felt like never-ending winter. I also liked Tompkin’s collaboration with Oswald Berthold (of farmersmanual), recur⁵ by tsx.

David Lowery – The Green Knight (A24). Really enjoyed this film version of the Arthurian legend of Sir Gawain and the Green Knight. There are enough layers of symbolism and mystery given to telling what is essentially a short and simple story that it offers multiple interpretations, and makes me want to watch it again. It also makes me want to re-visit Lud’s church, in Derbyshire near the Staffordshire border, which is said to be the likely location of the green chapel where the tale of the Green Knight ends.

Luke Lund – Helikaalinen (Helical) (Fluf). Complex music based on mathematical and physical processes, with some really nice generative artwork on the CD too. I also enjoyed the other release from Fluf this year, the future made me hardcore by tuuun.

Motoko & MyersColocate. 2nd album by Wonja Fairbrother and Daniel Letson. Smooth, slinky and funky.

Milton Nascimento & Lô Borges – Clube Da Esquina (Odeon, 1972). Like the Nuno Canavarro album, if you know this you love it, and it’s one I should’ve listened to before but hadn’t. One of the greatest records ever.

I watched a few music documentaries, all good: Sisters With Transistors about female electronic music pioneers, In A Silent Way about Talk Talk’s album Spirit of Eden, Freakscene: The Story of Dinosaur Jr., The Velvet Underground, Tom Petty: Somewhere You Feel Free – The Making of Wildflowers and Other, Like Me: The Oral History of COUM Transmissions and Throbbing Gristle.

Else Marie Pade – Electronic Works 1958 – 1995 (Important Records). Early compositions by the Danish pioneer of musique concrete. Sustained metallic tones comprising different kinds of beating frequencies. Somewhere between the timeless meditative drones of Eliane Radigue and the in-your-face here-and-now of Maryannne Amacher’s otoacoustic work.

Bernard Parmegiani – Stries (1980) for 3 synthesizers and tape (ina GRM). This is the first complete recording of the three-part composition, performed by Colette Broeckaert, Martin Lorenz and Sebastian Berweck.

Hannah Peel – Unheard Delia (Electronic Sound). A translucent yellow 7″ record that came with issue 75 of Electronic Sound Magazine. Two compositions feature bits from an interview with Delia Derbyshire combined with Peel’s music. Download a rip of the vinyl here:

Ellen Phan – Visual Squash (anòmia). Electronic music based on the artist’s experience working in neuro-linguistic programming using equipment that measures the intensity of emotional states.

PRESSURE CARCASS – DISCO EXTERIOR. During an interview with Martin J Thompson about my album Disorganised and Unwanted, I mentioned that there weren’t many other albums with a similar proportion of mostly field recording and some effects. I struggled to remember any particular albums, so I failed to mention this one by Louis Johnstone (WANDA GROUP). No-one else does it like he does.

Nasser Rastegar-Nejad – Music Of Iran, Santur Recital (Lyrichord, 1964). A good quality recording of a virtuoso performance on the santur, a type of hammered dulcimer. You can get a vinyl rip of this album as FLAC or MP3 from here: Through the Trunk Records email I heard about the music of Michael O’Shea, who plays a related kind of instrument that he built from an old door and played with paintbrushes which he called Mo Chara (‘my friend’). See him in action in this appearance on RTE in 1980: And listen to his only album here:

Jules Rawlison – Yield Point. The sound of what happens when you mangle virtual brass instruments, deforming pitch and timbre through stochastic processes applied to physical modelling.

Jim O’Rourke – Steamroom 53. I think the title ‘6 views of a secret’ suggests this is a Cubist piece of music, a single work made of multiple approaches to the same thing. It comprises six successive sections separated by silences. In Cubist art, individual objects are composed of multiple pictoral forms as seen from different points of view. In this Cubist music, multiple musical forms are composed of a single set of musical objects – wood block, organ, bell, and strings plucked, hammered and bowed. In musical Cubism, the temporal relations of the multiple views are inverted – succession instead of simultaneity, but the effect is equivalent – a kaleidoscopic collapsing of space/time.

Sambrasa Trio – Em Som Maior (Som Livre, 1965). A tip from Sasha Frere-Jones. Humberto Clayber (bass), Airto Moreira (drums) and Hermeto Pascoal (piano). If you haven’t seen the video of Hermeto Pascoal playing in a lake, then treat yourself.

SDEM – Fliter (SUPERPANG). Part of SUPERPANG’s new series of live performances, this is an absolute banger from SDEM. Two other albums were also great: RAG ORDER and SYNCAV.

Akira Sileas – Tricorn Centre (Hard Return). I like everything that Jack Chuter puts out on the Hard Return label. This is some nice techno. Other favourites were Cypro – I Have Eaten From The Timbrel I Have Drunk From The Cymbal, and en creux – The Water.

SOPHIEBIPP (Autechre Mx). RIP SOPHIE. This rips. Compared with most other Autechre remixes, this is quite a subtle treatment, but it brings out some of the best bits of this tune and of SOPHIE’s voice.

DJ Sprinkles – Gayest Tits & Greyest Shits: 1998-2017 12-inches & One-offs (Comatonse Recordings). I could’ve sworn this was released last year, maybe because it seems so familiar now, having listened to it loads, but it came out in 2021 alongside a re-release of Midtown 120 Blues which is equally good. Every track shows great skill and attention to detail. I particularly like ‘Useless Movement’ featuring the voice of Laurence Russell talking about a feminist critique of French literary theory, where the rhythm of the words is gradually looped and layered. The last track is amazing: ‘Admit It’s Killing You (And Leave) (Sprinkles’ Dead End)’ is a deep house tune nearly 15 mins long with a 5/4 beat that makes a political point through use of samples and has a weird glitchy breakdown in the middle. It shouldn’t work, but it does.

SYNALEGGComputer Series (OOH-sounds). In terms of which artists are approaching anything like Autechre’s recent output, it’s a close call between SDEM, William Fields and SYNALEGG.

Tokingake. A collective of artists and a label based in Japan that’s put out some of the most interesting sounds this year, starting with a collection of compilation albums including music by a0n0, IKTS, peeq / nankotsuteacher, Kenji Hamada, nzworkdown, Kagami Smile, and The Worst Vegetable Corner.

Valery Vermeulen – Trailer of Mikromedas AdS/CFT 001 (Ash International). Six sonifications of data streams generated from mathematical models of black holes. Sounds suitably dark and ominous.

Ben Wheatley – In the Earth (Universal Pictures). The first film I saw in a cinema this year after the end of the second lockdown. A supernatural tale set in a deep woodland whose unusually fertile earth is being studied by researchers during a pandemic. Part black comedy, part techno-pagan eco-mythology. The strongest element is Clint Mansell’s music, which is not just a soundtrack but a central part of the story.

Various artists – Get This: Thirty Tracks for Free – A Tribute to Peter Rehberg ($ pwgen 20). This album hasn’t yet been released; it’s due out in January. It’s the result of a collaborative project that I’ve been involved in for the past few months, which started out small but snowballed into something bigger and better than we’d anticipated. It features music by friends and fans of Pita, including many Mego artists. I’m looking forward to being able to share it with you.

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Permutation Entropy

Permutation entropy is a measure of complexity developed for application to time series data. I wasn’t familiar with this measure until Yoichi Ichikawa (peeq / nankotsuteacher, one of the Tokinogake crew) mentioned it on Twitter, noting that it could be applied to acoustics and therefore might be useful for making music. The tweet linked to a 2017 article written in Japanese, which I can’t read, so I found a copy of the article that first proposed the measure: Bandt & Pompe (2002) Permutation Entropy: A Natural Complexity Measure for Time Series.

I said I’d see if I could implement permutation entropy in Mathematica. It was a struggle to work it out from the original article, but this blog lays out the steps involved, and using that as reference I managed to write some code that does the job.

Here’s how the permutation entropy (PE) measure works. PE is an average of the frequencies of order patterns in a one-dimensional series of data, based on comparisons of neighbouring values. This is done by breaking down the data series into smaller chunks, working out the ordinal rank of data in each chunk, identifying which of the possible order permutations it matches, then summing the numbers of permutation patterns. The size of chunks, specified in terms of the number of data points they contain, is called the embedding dimension, (n). The distance between the starting point of each chunk, also specified in terms of the number of data points, is called the embedding time delay (d).

In Mathematica I used the same example provided by Bandt & Pompe and the blog that explains it, with parameters n = 3, d = 1, and the same list of data: (4, 7, 9, 10, 6, 11, 3). That way, I could check to see if the code was working. Below, input code is represented in bold text and output in plain text.

First assign the list:

list = {4, 7, 9, 10, 6, 11, 3}

Break the list into chunks of size n = 3 with delay d = 1. Because d < n, the chunks overlap:

With[{n = 3, d = 1}, Partition[list, n, d, {1, n}]

{{4, 7, 9}, {7, 9, 10}, {9, 10, 6}, {10, 6, 11}, {6, 11, 3}}

Calculate the ordinal rank of numbers in each chunk (the example in the blog counts from 0, whereas Mathematica ordering counts from 1, but it doesn’t make any difference as long as you identify the permutation patterns consistently). In Mathematica, the ‘Ordering’ function calculates the position of sorted list in list, but what we want is to calculate the position of list in sorted list. This can be achieved by applying the Ordering function twice (I am grateful to Yoichi Ichikawa (peeq / nankotsuteacher) for spotting the error in this calculation, which allowed me to correct it):

With[{n = 3, d = 1}, Map[Ordering[Ordering[#]]&, Partition[list, n, d, {1, n}]]

{{1, 2, 3}, {1, 2, 3}, {2, 3, 1}, {2, 1, 3}, {2, 3, 1}}

With n = 3, there are the 6 possible order permutation patterns:


{{1, 2, 3}, {1, 3, 2}, {2, 1, 3}, {2, 3, 1}, {3, 1, 2}, {3, 2, 1}}

Count the occurrence of each permutation pattern:

With[{n = 3, d = 1}, 
    Map[Ordering[Ordering[#]]&, Partition[list, n, d, {1, n}]], #]&, 

{2, 0, 1, 2, 0, 0}

Then divide these numbers by the number of chunks, which equals the number of elements in the list minus d × (n – 1) = 5:

With[{n = 3, d = 1}, 
 Map[Count[Map[Ordering[Ordering[#]]&, Partition[list, n, 1, {1, n}]], #]&, 
   Permutations[Range[n]]]/(Length[list] - (n - 1) d)]

{2/5, 0, 1/5, 2/5, 0, 0}

Finally, PE is the sum of the logarithm (base 2) of those numbers (the probabilities of the distribution of permutation patterns), calculated with the following equation (where p(π) = the probability of each pattern):

H(n) = –Σ p(π) log p(π)

With[{n = 3, d = 1}, 
  Total[Map[# *Log[2, (#)]&, 
           Partition[list, n, d, {1, n}]], #]&, 
        Permutations[Range[n]]]/(Length[list] - (n - 1) d), 
      0]]*-1]] // N


That equation gives a value between 0 (for a uniformly increasing or decreasing list) and log2n! (for random lists), which for this example = 2.58. The measure can also be normalised to give a value between 0 and 1, by multiplying the result by 1/log2(n!):

With[{n = 3, d = 1},
  Total[Map[# *Log[2, (#)]&, 
           Partition[list, n, d, {1, n}]], #]&, 
        Permutations[Range[n]]]/(Length[list] - (n - 1) d), 
       0]]*-1] * (1/Log[2, n!])] // N


From this code, a function can be defined whose input is a list and the values for n and d:

permutationEntropyNormalised[list_, n_, 
  d_] := (1/Log[2, n!])*
   Total[Map[# *Log[2, (#)]&, 
           Map[Ordering[Ordering[#]] - 1&, 
            Partition[list, n, d, {1, n}]], #]&, 
         Permutations[Range[n] - 1]]/(Length[list] - (n - 1) d), 
       0]]*-1] // N

Which allows us to shorten the code to a simpler expression:

permutationEntropyNormalised[list, 3, 1]


The result of this measure is a single number. Reducing a bunch of data down to a number may be useful for measurement, but less so for generative musical purposes. For actual time series data, which is much longer than the example above, PE can be calculated on a sliding window across the dataset, with the result being a series comprising a PE measure for each window position, which aligns with the original data (actually, it’s always a bit shorter – it starts from a point in the data equal to half the window size, and it ends the same distance before the last value). This is more useful for creative purposes. For example, a recording of an instrument could be analysed, and the PE measure output could be used to control video graphics in time with the original. Creating a sliding window of data can be achieved the same way that the data is split into chunks (but the window size must be greater than the chunk size n). This function, which incorporates the previous function for normalised PE, calculates PE using a sliding window:

peWindowAnalysis[list_, n_, d_, window_, delay_] := 
 Map[permutationEntropyNormalised[#, n, d]&, 
  Partition[list, window, delay, {1, window}]]

I tried this with some short audio files made of test tones. The first was a 0.5 second 20 Hz sine wave at -6dBFS, whose waveform looks like this:

Using a sliding window size of 128 samples, this is the PE output:

The highest PE values (≈ 0.4) appear to coincide with the waveform peaks, where the audio data is more varied in terms of permutation patterns, in contrast with the up or down slopes of the waveform which comprise fully ordered data. Maybe this kind of data is not really the sort of thing that PE was designed to measure, but it’s useful to do these tests to understand how it works.

Then I tried a 0.5 second sine wave linear sweep from 20Hz to 20kHz, which produced the following:

This is quite interesting. The PE value goes up to 1 at around 15kHz, with a sharp drop down to 0.6 near the highest point. It’s surprising that this simple sound produces PE values up to the maximum, which should apply only to the most disordered data. It’s also odd how the PE measure varies with the frequency of the sine wave, increasing and then decreasing. I don’t know why.

Here’s the result for a logarithmic sweep (increasing slowly at the start, faster towards the end):

Compared with the linear sweep, the result here is the same but the left side of the chart is stretched and the right side is squeezed. The left part, where the frequency starts at 20Hz and slowly increases, looks similar to the first result with the steady 20Hz tone. But that regularity begins to break down above a certain frequency, then PE increases as the frequency increases.


There’s probably a more elegant/efficient way to do program this algorithm, but I lack the mathematical and programming skills to achieve that. This one works well enough, though. Computer memory is the main limiting factor, due to the large number of permutations when n increases. My PC can cope with n values up to 9 before running out of memory. Bandt & Pompe recommend a value from 3 to 7. But different n values produce different results – in general, as n increases, PE decreases. For example, here’s the PE measures for a list of 100 random numbers between 0 and 10 when n ranges from 3 to 8:

With[{list = RandomInteger[10, 100]}, 
 Table[permutationEntropyNormalised[list, n, 1], {n, 3, 8}]]

{0.979155, 0.94358, 0.845143, 0.675794, 0.531198, 0.426012}

In this example n = 3 gives the highest value and therefore the most accurate result, but intuitively it seems that larger n values should give better results. I’ll run more tests to see the effect of different n values and different window sizes, and I’ll report the results here if there’s anything interesting. It will also be interesting to see how it fares with longer and more complex audio, including music.

PE gives higher values for more random data, just as Shannon’s measure of information entropy does. Both differ from our intuitive sense of what ‘complexity’ means because they actually measure disorder (but that’s a whole separate subject, covered in my PhD thesis). There is one way in which PE and Shannon entropy differ greatly, however: A list of ascending numbers – such as the range of integers from 1 to 100 – has a minimal PE value of 0, but also has a maximum Shannon entropy (because the data cannot be compressed). In contrast, a list of identical numbers – such as ‘1’ repeated 100 times – has a minimal value for both PE and Shannon entropy. Nevertheless, this measure of complexity “has been applied to optical experiments, brain data, river flow data, control of rotating machines, and other problems” (Bandt, 2016). So it might also be interesting for applying to audio analysis, and maybe potentially useful for music creation.

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We Are Happened 2020/08/26

I was invited to talk about my latest album, Disorganised and Unwanted (Day/Night), on the We Are Happened programme on Camp Radio. I chatted to Martin J Thompson, who runs the SM-LL label and who mastered my album. We mainly talked about field recording and noise. Kind of appropriately, my end of the line is quite noisy, with boxy reverb from the room, and in the background you can hear traffic, sirens, desk/chair noise, and computer hum. I also pronounced some people’s names wrong (apologies to Rian Treanor, Jana Winderen and Pantea). The show was broadcast on 26th August, and is now available to listen to here:

We Are Happened is run by Lucia Cheung, who also produces music as en creux. Her latest release on Hard Return is worth checking out – two long-ish drones made of ostensibly static sounds that burble and fizz with small chaotic disturbances:

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Disorganised and Unwanted

I have a new double album out on the Tokinogake label. It’s based on field recordings made over the past 10 years, mainly around where I live in Nottingham but also in Derbyshire, North Yorkshire and Rutland. The tracks are split into two albums – day and night, when the recordings were made, and they’re in roughly chronological order. The recordings are processed in various ways:

  • Adding synthesized sound, triggered by volume levels/changes in the source audio
  • Inverting the loudness levels of the audio
  • Applying effects with parameters shaped by the audio volume level
  • Using Fourier re-synthesis to extract the dominant frequencies / noise bands (a bit like time-stretching without the stretching)

Most of these techniques I developed in Disquiet Junto projects. Two of the tracks on the album are versions of tracks submitted to the Junto: ‘Shrewsbury Road’ (project 0218 – Sound Passage) and ‘Shrewsbury Road Rain’ (project 0029 – Count Zero).

A member of the Tokinogake collective, nankotsuteacher, correctly identified that some of these are the same sounds/processes as heard in Processed Field Recordings (20×20 Project, 2020). In an article on the Tokinogake website, nankotsuteacher also analysed the album in terms of Bernie Krause’s categories of sound: geophony (natural sound), biophony (animal sound) and anthrophony (human sound).

A central theme of the albums is unplanned and intrusive sound – the kind of thing usually edited out of field recordings, like microphone handling noise, wind noise, traffic and human voices. Listening to the original recordings, some of these noises were more interesting than the intended sounds, and over time they began to form a nice collection. So instead of removing them from a set of compositions of clean sounds, I turned them into focal points for new compositions.

‘Unwanted sound’ is one of the main definitions of noise. Noise may also be understood as the opposite of music, which is sometimes defined as ‘organised sound’. Film theorist and composer Michel Chion was one of the first to articulate these two ideas about noise. My approach to noise in this album is informed by Marie Thompson’s research on this subject which “critically rethink[s] the correlation between noise, ‘unwantedness’ and ‘badness’.” Thompson’s Beyond Unwanted Sound is available as PhD thesis [PDF] and book.

Whether good or bad, generative or destructive, overwhelming or unheard, noise […] is always affective. Indeed, affect can be understood as the connecting thread that underlines noise’s informational, social and aesthetic manifestations. Noise’s affectivity is as central to encounters with noisy neighbours as it is to Yasunao Tone’s glitching and stuttering wounded CDs; to crackling telephone conversations as it is to the quiet improvisations of onkyô.

Thompson (2014) Beyond Unwanted Sound, p.239
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Credit Roll

Back in February, I agreed to help Enric Farrés Duran and Ricardo Duque with the technical challenge of making a video that would show thousands of lines of scrolling text. The text listed the entire archive of MACBA, a museum for contemporary art and culture based in Barcelona. The challenge was to turn this into scrolling credits like you get at the end of a film or TV programme.

The video is now part of an exhibition called Coses que Passen (Things that Happen) that celebrates the 25th anniversary of MACBA’s archive and research centre. The project led by Enric Farrés Duran explores and questions the museum’s archive, based on a research process that recognises that “an archive is not only made up of the documents it contains, but also everything that allows them to be available”. In other words, an archive is not only the objects it contains but also the physical environment in which they are kept and the intangible information systems that organise and document them. In this case, MACBA’s archive comprises over 6,000 works, which amounted to around 45,000 words or 12,000 lines of text.

To make the video I used the free command-line program FFmpeg. I’ve used it previously for making animations from still image files, for adding audio to those videos, and for converting to different file types and encoding formats. FFmpeg code specifies the input and output files, plus any extra options. At its simplest, the code looks like this:

ffmpeg -i input.mp4 output.avi

It’s possible to create a video of scrolling text using FFmpeg’s drawtext filter which is part of the libfreetype library. Drawtext allows you to input text from a text file. So the first task was to convert the Excel spreadsheet into a text file and to format it to display correctly. The drawtext function has limitations on styling options that we had to work around. For example, it doesn’t wrap text, which meant that we needed to work out a suitable line length to split the text file into, and to split the lines without splitting words. The text needed to be centred horizontally, but FFmpeg would only centre-align the whole text instead of aligning each line individually, which meant that we had to add the correct number of leading spaces to each line that was less than the maximum width. Using a font with letters of different widths made some lines off-centre, which meant we had to use a monospace font. So it took a lot of trial and error to get the settings right – including line length, line spacing, horizontal position, scrolling speed, font size, image dimensions and frame rate – until the output video was as the artists wanted it. Here’s the final code (file paths replaced with generic names):

ffmpeg -f lavfi -i color=black:s=1920x1080:rate=60,format=rgba -ss 00:00:00 -t 01:40:00 -vf "drawtext=fontfile='Basis Grotesque Mono Pro Medium.otf':fontsize=36:fontcolor=0xF8F6E9:x=(w-text_w)/2:y=h-100*t:line_spacing=4:textfile='text.txt':expansion=none" -c:v libx264 -y -preset ultrafast output.mp4

It took 14 hours to render the video, which was 1.5 hours long and just under 1GB. Below is a screenshot from the video, and photos of the exhibition. You can see the exhibition via MACBA’s virtual space, including a video of a guided tour by the artist.

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