Making pure infrasound on a budget

Our infrasound generator was built on a very small budget – it was designed by Peter Lord of the UK National Physical Laboratory on the acoustic canon principle. Here’s a brief description – I’ve written this summary several years later, from memory, on request from various correspondents so please excuse any details that are missing. This description assumes the reader has a basic understanding of the physics of sound:

Safety warning and disclaimer

As infrasound is felt rather than heard, be wary of working with it. Monitor levels with calibrated equipment at all times. You may be working at sound pressures high enough to damage hearing or objects, without being aware of the exposure. Levels may vary markedly in a room. For a low-frequency monitoring device, look at microphones used in bioacoustics or geological research. These notes are given for guidance only – please take safety precautions and conduct your own risk assessment before working. Any work conducted with infrasound is at your own risk.

Pure tone

For our experiment we needed a very pure infrasonic note, with no harmonics, extraneous noise or other sounds in the audible spectrum that might give the presence of the infrasound away. We just wanted to hear the fundamental frequency of the pipe. This ruled out building an organ pipe of any kind – organ notes have a rich timbre because they are also rich in harmonics.

Our acoustic canon was made from stiff sewer pipe around 7 metres long. We placed an extra-long-stroke subwoofer around 2/3 of the way down this. Thus, it was stoppering a pipe around 4.7 metres long – one that was open at one end. In theory, this gives a resonant frequency around 17.5Hz (or at bit lower, when end correction is taken into account). NB We confirmed in tests this behaves as a quarter-wavelength pipe (not a half-wavelength) – effectively it functions like a pipe that’s open at both ends.

Why an extra-long-stroke subwoofer?

To create infrasound that’s perceptible, we needed to move a large volume of air every cycle of the soundwave. A domestic subwoofer does not have a long enough stroke to do this. The extra-long-stroke is a servo-driven speaker that has movement of necessary amplitude. Using a signal generator, connected to the speaker via a power amp, we were able to create infrasound with low distortion (but inevitably some distortion due to imperfections in the system).

Everything in the signal path, from the signal generator to the power amp and the subwoofer itself had to work efficiently around our 17-18Hz target frequency. We bought a Yamaha power amp that had a cut-off of 10Hz.

Mounting the pipe

We commissioned exhibit makers Tim Hunkin and Graham Northgate to adapt Peter’s design so it would fit in a transit van. They made it from three sections which clipped together tightly using flight-case catches. They also built stands for it and a steel suspension wire to prevent the pipe from drooping under its own weight. When we switched on the pipe, it soon became apparent that the suspension was itself a cause of distortion – it buzzed and rattled. We fixed this with some neoprene rubber on the mounts.


On switch-on day in Tim Hunkin’s barn (see photo), there was trepidation in the air as we gradually increased the amplitude of the signal generator. To our relief, the pipe resonated strongly at 17.5Hz and the infrasound was well above the threshold of perception. In the close quarters of the barn, the infrasound began to resonate strip lights, furniture and other loose odds and ends. At the pipe made very little audible sound, this was a disconcerting experience. Seeing these objects in motion for no apparent reason, it’s easy to imagine how infrasonic energy could be mistaken for a ghostly presence.

Spectrogram during a concert

Here’s a spectrogram showing the pipe in action during our concert in the Purcell Room, London, 31 May 2003. Audible music is being played at this moment too. You can clearly see the infrasonic pure tone at an SPL that far exceeeds the other sounds in the room. Source: Peter Lord and Dan Simmons, NPL.

Alternative technique: a resultant note?

Since we conducted this experiment, there have been various other interesting attempts to investigate the subjective effects of infrasound. Studies have involved musicans, parapsychologists, architects and others. Many have tried to overcome the practical difficulties of building a pure infrasound generator by creating an infrasonic ‘resultant bass’. However when investigating infrasound, I think this resultant technique is hugely problematic.

When we play two pure tones in the room together, a perfect fifth apart, our brain percieves a resultant an octave below the lower note (see this very helpful description by Colin Pykett, 2011). The sound we’re hearing is a ‘beat frequency’ – a resulting fluctation in the envelope of the combined sounds. At low frequencies, it feels like a deeper bass note in the room, an octave below the lower of the two notes. This technique is commonly used by organists who want to give the impression of a bass an octave below the stops they actually have at their disposal. However, in order to create that fluctuation, higher notes are present (the ones creating the effect). Therefore if you’re using a resultant to create infrasound, you’re actually exposing your test subjects to notes at higher frequencies. These are highly likely to mask or swamp any effects of the infrasonic frequency itself. I have yet to see a paper using resultant infrasonics that adequately addresses this issue.



In a film screened at Latitude Festival, 2011, dancer Louise Colborne presented her own interpretation of Loie Fuller butterfly dance.

Dancer at the Folies Bergère in the early twentieth century, Fuller was a pioneer of multimedia performance. She projected coloured lights and images onto her volumous, silk dress. Sticks inside her sleeves extended her arms, creating an other-worldly augmented human performance.

When Louise saw me play a short theremin set, she was struck by the connections between the movements of a thereminist and those of early dancers such as Fuller. She asked me to play theremin for her film which interwove the theremin performance and the dance.


Reanimating a submarine with sound

Over the winter 2013-14, I swapped my studio for submarine HMS Alliance where I’ve been installing a new, generative (i.e. algorithmically controlled, ever-changing) 50-channel sound piece.


HMS Alliance is a thing of wonder: the UK’s last surviving WWII-era submarine. Work on Alliance started in 1945, she was ready to go to sea in 1947 and was in service for three decades. Alliance patrolled the oceans and conducted cloak and dagger missions during the Cold War (no-one will officially say where, exactly). She’s now open as a museum and a memorial to other Royal Navy submarines lost at sea, including her sister, The Affray, which sank in 1951 with the loss of 75 lives.

If you step inside Alliance, you’ll see she still has almost all her original fixtures and fittings – from the periscope and diesel engines to the ship’s telegraph, the Q-tank valves, the underwater telephone, the galley, the heads (toilets and sinks) and the bunks where the 65 men on board took turns to sleep. Very little of this equipment is operating any more (although much of it is still in working order) so I was called in to reanimate the submarine with a naturalistic soundtrack, evoking the submarine’s past. I worked very closely with veteran submariners to create the world on board. Submariners from the post-war era relied on sound – and silence – to survive so have a remarkable ability to recall and describe sonic details, right down to the pitch of a propellor. Over many weeks, through trial and error, we piece together a soundworld which faithfully reflected their memories.

HMS Alliance ship's telegraph

The veterans, retired Royal Navy submariners, also work as a very knowledgeable and helpful band of volunteer guides. This sound piece has been designed with two working modes: one where it provides a theatrical undescore for their guided tours; another where it fills the entire submarine with sound, when visitors wander the submarine alone.

There’s more about this project in Leila Johnston Hack Circus. Meanwhile, here’s a walkthrough the submarine on the eve of opening:

The lead designer on the project to reanimate HMS Alliance was Henry Lyndsay. Henry is a former Imperial War Museum designer who now works independently.

The Odditorium is a compendium of eccentrics, trickers, deviants and obsessives, many of whom are largely unacknowledged in the usual histories of science, politics and the arts. This book has been compiled and edited by David Bramwell (founder of the Brighton salon The Catalyst Club) and Jo Keeling, publisher of Earnest Journal.

“…the most sensational plant in Britain – like a thing from outerspace”. Muriel Howorth with her ‘atomic peanuts’.


‘ve written a chapter on the extraordinary life of Muriel Howorth, an amateur nuclear scientist who experimented during the Cold War in the UK seaside town of Eastbourne. Inspired by scientists at Oak Ridge, Tennessee (home of the Manhattan Project), Howorth composed and directed her own amateur atomic ballet Isotopia. She also founded the UK Atomic Gardening Society – an example of citizen science and mass experimentation, conducted through the Post Office.
The Odditorium

Hear Ealing Feeder

Buy on Bandcamp

London, a modern edifice on a mediaeval footprint, is the blueprint for Ealing Feeder, a steely, unsettled love letter to the city.

Devised over many years of performance, some tracks will be familiar to people who’ve seen Sarah’s live act, others are entirely new. A Wren in the Cathedral, set in Limehouse, collides electron theory with city birdsong and Hawksmoor’s architectural formalism. Cow Heart Pin is inspired by a London butcher in the 1920s who impregnated a desiccated heart with nails to curse a rival. The Bows recalls a transfiguration myth on the River Thames. Sky Bullion reflects on some of the more venal forces shaping the city skyline today.

This work – the first to distill Sarah’s solo set into an album – reflects the ecletic nature of her music making. An electroacoustic composer with a deep interest in the history of electronic music, as a teenager, Sarah cut her teeth as a live musician in folkclubs. Her formal musical education was in Baroque and Renaissance music, yet she builds and performs with her own robotic inventions, viewing them as a theatrically compelling alternative to the laptop. Through music, she explores resonances between folklore and early notions of telecoms and machines. Among these tracks, you’ll hear examples of augmented theremin technique (for instance using theremin to control birdsong), robotic carillon (an instrument Sarah designed and built to play riffs at inhuman speeds) and her unusual take on the loop pedal. This variant stretches every strand of sound subtly as it plays, transforming the most consonant music into something more angular as it makes beguilling, unexpected musical collisions – something with a family resemblance to Renaissance music.

Ealing Feeder is composed, performed and produced by Sarah Angliss using theremin, recorder, saw, spinet, robotic carillon, field recordings and Max. With thanks to the following guest artists:

Jenny Angliss – vocals (The Messenger)
David Bramwell of Oddfellows Casino – vocals (Cow Heart Pin)
Flora Dempsey – spoken word (The Messenger)
Emma Kilbey – spoken word (The Bows)
Stephen Hiscock – percussion (A Wren in the Cathedral, The Fancy Cheese People, Sky Bullion and Fever Van)
Colin Uttley – spoken word (A Wren in the Cathedral, Ventriloquist and Fever Van).

Ealing Feeder (back cover)Ealing Feeder (back cover)

Track details

[01] You Taught Me How to See the Crows

Counting and feeding the gathering crows from a window that’s level with the London tree canopy. Performed live in one take using solo recorder and Max. The Max patch reiterates the live recorder while subtly stretching it in time.

[02] A Wren in the Cathedral

Here, a theremin coalesces with the song of a wren in this piece inspired by Stoppard’s description of the random movement of electrons in an atom. Sarah uses Max to augment the theremin, moving seamlessly from a classic electronic instrument to a birdsong controller.

[03] The Bows

Inspired by London folksong ‘The Bonny Bows’ (also known a ‘The Cruel Sister’). In the original song, a woman murders her sister by pushing her into the Thames. When the corpse is dredged from the water, the breastbone, hair and fingers are used to make a fiddle which speaks, revealing the identity of her murderer.

This version uses Sarah’s recordings made in the Submarine Emergency Escape Training Tank, Gosport, just before it was decommissioned.

[04] Ventriloquist

Incorporates an excerpt from Wordsworth’s autobiographical poem The Prelude, listing the attractions in Bartholomew Fair, Smithfield.

[05] Camberwell Beauty

The beauty here is an old Camberwell piano that was given to Sarah three years ago, lifting her spirits after she’d sold her own piano to pay the rent. The Camberwell was such a wreck, it didn’t make the cut on this album – but it did catalyse her to begin playing again. She used the Camberwell extensively on the soundtrack for Eugene O’Neill’s The Hairy Ape (at The Old Vic, then The Armory, New York) – a commission that bought her a new piano and paid the rent.

The bells on this piece are played by the ‘Ealing Feeder’ – the polyphonic, robotic carillon Sarah built to play riffs at lightning speed.

[06] The Two Magicians

Reimagining the transfiguration myth in the English folksong The Two Magicians, in which two men continually shapeshift as they chase one another to the death. This version moves the action to Lucha Britannia, a masked wrestling club in Bethnal Green. With thanks to Lucha Britannia and photographer Gaynor Perry.

[07] The Fancy Cheese People

The Fancy Cheese People was a 1960s warehouse on the Farringdon Road which mysteriously seemed to do very little business. At the time of its demolition, around 2002, it was revealed to be a front for MI6.
Sheep heart amulet in the Lovett collection (source The Wellcome Collection)

[08] Cow Heart Pin

A curse that may be mistaken for a love song. It’s inspired by an account in Edward Lovett’s ‘Magic in Modern London’ (1925). Lovett writes of a butcher in East London who impregnates a desiccated cow’s heart with nails and pins to curse a rival. Sarah adapted the words from some Anglo Saxon cunning magic, used against someone who has stolen cattle.

[09] Caul (Vardøger)

A short piece, inspired by an account in Edward Lovett’s ‘Magic in Modern London’ (1925). During World War One, Lovett noted a resurgence of interest in amulets containing a caul – the preserved amniotic sack of a baby born with the membrane intact, covering the face. Sold around the London docks, the caul was seen as a magical object which could protect the wearer from drowning.

The vardøger is a Scandinavian Doppelgänger – one who traces your actions a few minutes before you do. The vardøger may have arrived in the docks with the London wood trade.

[10] Sky Bullion

An expression of all that is venal about London property speculation. ‘Sky bullion’ is a term used by those using the London property market as a safe haven for money. Sarah asked percussionist Stephen Hiscock to extemporise with a recording made that morning of the building site outside her flat – this was the result.

[11] Fever Van

In the 1930s, before the vaccination era, the fever van removed contaminated Londoners from their homes, transporting them to the fever hospitals. This track mixes the sound of London sirens with the words from Ushers Well. In this folksong, a woman is visited by her three young sons who have died while away from home.

[12] The Messenger (Alexandra Palace Mix)

Inspired by an early imagining of mobile telecommunications, published at the end of the nineteenth century in an engineering magazine. This is Sarah’s original version of a track that was reworked by Belbury Poly for the Ghostbox Study Series. Featuring archive recordings from Prelinger and the NASA Cassini Probe.

A video of a performance of The Machinery at AlgoMech, Sheffield (with dancer Caroline Radcliffe). Video by Jon Harrison. This was an ad hoc video and give a great view of the steps but do not show the projections which are beind the dancer.

Update June 2018: We’re now working with Jon to make an archival-quality video of the dance in a studio (more details coming soon).

Read more about the dance – includes link to TEDx talk Loving the Machine


In this optimistic view of mechanisation for TEDx Brighton (2011), I revealed some surprising connections between two types of dance music which flourished two centuries apart. Both were created by people were working to the relentless beat of factory machines.

This talk uses some of my original research for the Science Museum, London, as well as the results of a collaborative project with performer and theatre historian Caroline Radcliffe. It was a response to the theme of the conference: Reasons to be Cheerful.

Read some background notes on this dance, including references to peer-reviewed publications.

Decades before the era of laptop-based algorithmic music, systems artist Channa Horwitz used paint, pencil and paper to precisely map out mathematically rich instructions for dance, light and music.

Mark Fell and I each interpeted Sonakinatography III, one of Horwitz’ systems pieces from the early 1970s, as part of a retrospective of her work at Raven Row gallery, Shoreditch (10-12 March 2016). My interpretation used bell samples controlled and repitched in Max to faithfully follow Horwitz’ graphical instructions.  This music accompanied dance choreographed by Ellen Davis, Horwitz’ daughter.

Sonakinatography I (fragment) - Channa Horwitz

Photo: fragment from Counting in Eight, Moving By Color, Time Structure Composition # III, Sonakinatography I (Channa Horwitz).

New opera in development

In 2016, I was delighted to be awarded a Jerwood Opera Writing Fellowship for a new chamber opera, Giant, based on the life, death and contentious afterlife of Charles Byrne. This is supported by Jerwood and Snape Music.

Byrne’s story is dramatised by just four singers (SATB) and a small chamber ensemble, including a solo viola da gamba, percussion and some of my robotic instruments. All of these perform acoustically, occasionally augmented by live electronic processing (using Max/MSP).

Max patch for giant - Sarah AnglissThe librettist is Ross Sutherland, a poet whose work I’ve admired ever since I saw his live show Standby for Tape Backup in which live poetry is tightly coupled with recorded visuals, to eerie effect. Funding from Aldeburgh Music and Jerwood Charitable Foundation has given us the time, space and mentoring we need to take on such an ambitious project – our first operatic work. I’ve also taken on director and dramaturg Sarah Fahie who has been helping us to structure the libretto and the staging of this musical work. Sarah has many years experience directing all aspects of opera.

June 2018: The libretto was completed in 2017 and  I’ve been developing the first few scenes of the piece with Sarah, Ross, singers and musicians. Unusually for opera, we’ve been workshopping this as though it’s a devised theatre piece, prototyping scenes with only the sketchiest of music in place.  I’ve found this process is essential to work out to pace a work of this duration. It’s given me a very clear picture of the each scene, moment by moment, in my head. Over the rest of 2018, I’m retreating into my studio to continue drafting rhe score.

Workshopping Giant – Britten Studio, Snape (March 2018)

Charles Byrne

Charles Byrne (1761-83), also known as ‘The Irish Giant’, had an extroardinary life because he was remarkably tall. Contemporary accounts differ but it’s now thought he was at least 7 feet 7 inches tall. In his lifetime, Byrne was considered a living wonder, a freak, a gentleman, a trophy, a fine performer, an ‘ill-bred beast’ and a person who held within his bones secrets that anatomists longed to understand. What we can say, definitively, is that Byrne lost sovereignty of his own body, surrendering it in life to alcohol and in death to the anatomists’ 
boiling pot. Byrne was betrayed by those around him. Against his wishes, his corpse met a fate that had terrorised him throughout his life. It’s debatable how much public prurience, professional vanity or the desire for medical progress prompted this betrayal—the tragedy at the heart of this opera.

Controversy over the fate of Charles Byrne’s body continues in 2016. When I first imagined presenting the story of Byrne, I couldn’t get out of my head the image of the funeral he longed for: his body in a lead coffin, carried over pebbles and into the sea, far from the hands of the resurrection men. I once saw a production of Blow’s Venus and Adonis and was mesmerised by the words ‘weep for your huntsman’ which are set so beautifully and sung as Adonis’ body is carried away 
(a breathtaking moment at the end of Act III). I want to attempt a work that includes a ritual this exquisite for a corpse that’s been robbed of such care. Thus an opera feels like a perfect way to tell Byrne’s story.