Around this time last year, we were approached by Cryptic about the prospect of bringing our Giant Feedback Organ to Glasgow in November 2015, to feature in its festival, Sonica.

We were looking for the next project to spur on our development of this instrument following the original commission by the Southbank Centre and we had long admired Sonica from afar, so we jumped at the opportunity.

Giant Feedback Organ

Until this point we had only been required to deliver two pipes and three notes; three very loud, low notes (F0, Bb0 and C1) but nothing beyond that to meet the requirements of the original commission. Naturally though, we had experimented throughout our early development of the instrument and this was a phase we re-entered with gusto following the go ahead from Cryptic. We borrowed a marquee from Sam’s local playing field association and away we went…

Four pipes, four spares

Eight pipes, no spares

Lowpass to chop off any unwanted squeals

Microphone mount to allow for microtonal pitch adjustment

Testing effects of orientation and proximity using the smallest pipe

Testing effects of orientation and proximity using a bigger pipe

Twatting about

During this development phase we moved from a four pipe system to eight pipes, with a set of secondary radiators duplicating the notes of their sister pipes. This added a certain weight to the sound. We also replaced our lowpass filters with something more flexible and expandable, added sprung microphone holders so those visiting the installation could alter the pitch of each pipe microtonally, and we tested the effects of moving the pipes relative to each other. All of this led to some very exciting results.

With everything tested and working, it was time to head to Sunny Glasgow.

Moving to eight pipes – four primary pipes and four secondary radiators – allowed us to fill the vast, cold, leaky warehouse space we were in with basssss. These pipes are big. The installation of them in the Tank Room of Glue Factory required us to heave!


Siliconing the speaker bungs in place

Cryptic crew, making things safe

Two pipes hung

The Glue Factory, filled with our tat…

Testing and tweaking
As ever when installing an instrument of this scale and register, it needs testing in the space itself. Within our test environment – the marquee in Sam’s garden – we were close to operating in a free field, so the exact effects of the space were not fully known. This is to be expected but is nonetheless daunting.

Fortunately, we have come up with a number of enhancements to our control system that allow for subtle tweaking and with some testing and measurement we were able to deliver a series of loud, low notes that interacted nicely in the space – sub one hertz beats and the like! The fact that we didn’t have to deliver any specific pitches provided extra freedom. Our remit in this case was to create an almighty racket in the space provided, which we duly did. It was time to let some people have a go. First up, ourselves and members of the Cryptic team…

Initial user testing

That went well but it was felt that the pitch adjustment might not be sufficiently obvious to some visitors, so some basic instructions were pasted onto the wall. The main issue we found was that with such low frequencies (and secondary radiators) it was sometimes hard to discern where the sound was coming from, and your affect on this. In fact each floor pad triggered the pipe directly above it, but even so this is an aspect we plan to enhance.

A few other challenges were to follow. RAIN! Water oozed through the walls of the building we were in, which was unhelpful. We also let party-goers loose on it one night, only for it to sustain significant damage, despite Sam’s best Shouty Voice. But overall, we are pleased to say it was as reliable as it had proved previously when installed at the Southbank Centre for six weeks.

The last use of the Giant Feedback Organ at Sonica fell to us, for the performance of our specially commissioned piece Octavism.

As Sonica artists-in-residence, we were commissioned to develop a new piece to be performed as part of the festival. This was our first time writing something we would perform using the Giant Feedback Organ; and it was to be accompanied by Sam on doom tuba!

We would go in each day before the installation opened to the public to structure and rehearse the piece. We found certain “sweet spots” in the interaction between the pipes and the tuba and then started to define the different sections of the piece. Beyond that, Octavism was improvised interplay between Sam on tuba and David on Giant Feedback Organ.

The piece lasted about 30 minutes. The performance was well attended and seemed well received. We took a lot from it and hope to build on it – details below.

Oh and we broke a Golden Rule by attempting to document our own performance. We think we just about got away with it.

David performing Octavism

Sam performing Octavism

Note: you will need to use good quality headphones or much larger than average computer speakers to hear the full spectrum of sound in this our first performance of Octavism.

What’s next for the Giant Feedback Organ?
Sonica was central in defining the future trajectory of our Giant Feedback Organ development. It was the first time we had performed with it ourselves …and it felt GOOD! Exploring the scope of the instrument – making it throb, scream and smoke – was a delight and Sam got rather jealous seeing David doing so.

The idea for GFO2.0 was born. Our focus is now on developing a two-player, eight-pipe version, where each player controls four pipes. This will enable us to respond to each other and a more expressive control system will allow us to thoroughly explore the scope of the instrument. We hope that this will ultimately lead to our instrument being played alongside others and to composers writing for it.

Oh, and lastly, we received one of the best reviews of our work to date for our time at Sonica. Michael Begg, writing in the Quietus, said of us:

“Refreshingly free of underpinning critical theory or concept”.



We are delighted to announce that our sound installation Amplification is currently included in the All Ears exhibition at Millennium Point in Birmingham. In association with Supersonic and funded by Arts Council England and Lintstock. We are very grateful for the support!

Here is the blurb:

Amplification is a stereo acoustic amplification system, developed to encourage deep listening to environmental sounds within a space. Users of the system will augment their listening through two large ear trumpets. In addition, they will be able to adjust the stereo field of what they can hear by swivelling each horn; creating a distinctive and unusual listening experience.

During their time exploring the collection at the Birmingham Museums Trust, MortonUnderwood was struck by the efforts made by developers of the music boxes, gramophones and orchestrions in the collection to amplify the sound output. In a world where we can easily dial in more electronic amplification, many of the innovative approaches seen in the collection are now obsolete. Through Amplification MortonUnderwood hope to highlight the beauty of passive, acoustic amplification systems.

Do go and have a look/listen…

Oh and if you like the look of this project, it fits in our van and is ready to tour! Please email if interested.

Funder logos


Despite keeping it pretty quiet on here, we have just completed a radio series via our project If Wet. Each month we featured music and discussion based on a different musical instrument, or class of instruments. We also had exclusive content provided for the show by a variety of makers and musical instrument designers.

This was a six part series; each show 2hrs long. Aired on Soundart Radio.

Series information/archive:
Radio website, with further information and podcast links:
Mixcloud archive:

With our first series complete we are looking to develop this further. Please email us if you are interested in discussing this.








Artist Craig Barnes has a unique work he has painstakingly restored. His Futuro House was due to be exhibited atop Matt’s Gallery in London when he approached us to develop some sound art for inclusion as part of its launch.

We consulted with Craig about the sort of atmosphere he hoped to create and arrived at an idea that involved us creating a series of drone “mantra boxes”. On tipping the boxes upright, each would start to play a long-form, bespoke recording we had created. The button on the side would cycle through eight recordings per box; each harmonious with the others. People entering the space could choose whether or not to interact with the boxes to form part of a group drone within the space.

The shape of the Futuro House leads to a distinctive acoustic, which the more sound-savvy visitors would exploit with our mantra boxes.






We were delighted to be invited to develop four sound art / sonic graffiti pieces as part of the inaugural Longbridge Festival Of Light. We worked with field recordings from Hannah Hull to create a series of light-responsive pieces that warped and mangled sound as light was introduced. Each piece was unique and played back through bespoke hardware we created.

As you come to expect when you install public artworks in harm’s way, these were used…and abused. But as the images testify, they appeared to bring joy to lots of people.








Portable slap organ

Portable slap organ - instructions

As part of a Town Hall Symphony Hall Birmingham schools project we designed and built two distinctive slap organs, or thongaphones. One featured as part of a garden-based sound installation in a Birmingham school, with the pipes collecting water for the garden. The other was a portable two-player slap organ for workshops.

As pictured above, we also provided a novel attachment for the portable slap organ that allowed them to demonstrate what it sounds like when air is blown through the pipes…

St Thomas garden slap organ

St Thomas garden slap organ

St Thomas garden slap organ

A Descent of mechanical woodpeckers is positioned within the public realm. You spot a colourful button. You press it and a note resonates across the space. You press it again and realise that a bird is perched overhead, pecking the surface of a post as you press the button. You spot other buttons, each triggering a bird that percusses a surface. You get it; someone has exposed the musical potential of this space. You play.

Earlier this year we were commissioned by Warwick Arts Centre and Capsule to create a sound art piece to be installed as part of Sonic Gorilla and then Supersonic Festival. At Warwick Arts five of the birds appear as a cluster within the main entrance space; two further pairs tapped a car park roof and the handrails of a footbridge.

Descent - Warwick Arts
Mechanical woodpecker perched high on a resonant metal post

This is a playful piece. It draws on various influences, including the philosophies of Cage and the instruments of Felix Thorn and David Byrne – in very much scaled down form – but we wanted to come up with a hook that made it immediately obvious what these things do. It was a nice moment when a family approached the controller unit, looked up and exclaimed “Look, woodpeckers!”. They knew straight away what the buttons would do…and they tapped out some wonky rhythms.

Descent - Warwick Arts
Control buttons for two woodpeckers perched three stories above

This was an original commission, and we experienced one or two issues with the mains powered controller when installed at Warwick Arts. Nothing we couldn’t patch in the short-term and fix properly before we installed Descent at Millennium Point, where the woodpeckers performed without fail for two weeks.

Descent - Millennium Point
Pair of woodpeckers at Millennium Point

It made us chuckle when we realised that the solenoids we were using were made in 1974 (before Sam was born) and we were coupling these with the latest 3D printing technology to make the woodpeckers.

Descent - Millennium Point
Pair of woodpeckers at Millennium Point

Descent - Millennium Point (blurb)
Descent blurb

This is a very rewarding project; it is great to explore each new space to find what sounds are hidden within it. Descent is ready to migrate, as a self-contained touring project, so please get in touch if you’d like our mechanical woodpeckers to pay your space a visit.

Many thanks to Katja for the Millennium Point photographs.

We recently made the trip to London’s Southbank Centre to remove our Giant Feedback Organ. It had been installed there since early March as part of the Pull Out All The Stops organ festival. This is the story of how it came about and what our plans are for it now…

Giant Feedback Organ demo – in Southbank rehearsal space
[decent headphones or very decent speakers required for a full fundamental experience]

In the beginning…

Sometime last year we saw this video. It was the best implementation of such a system we had seen and it provoked our usual response: Bigger, louder, bassier. At the time we were searching for something we might develop further. We added this to the list.

We always start testing with what we have lying around. In this case we used a powered monitor speaker and a standard vocal mic at opposite ends of some old carpet tubes we found in the shed. Initial results showed promise: we were able to make a decent racket in the 150-300hz range and by sliding one pipe inside another we could even “swanee” the feedback. Huge smiles all round.

Now we needed a better test rig. We replaced the vocal mic with one with a much extended low-frequency response, got a decent power amp and some bass driver loudspeakers. Then we approached our kindly local farmer who lent us some lengths of grain blowing pipe and joining clamps.

Test rig
Early test rig

To give us maximum space and flexibility, and as near to a free field as possible, we set this arrangement up in the garden. We soon discovered that the system resonated most willingly at higher order harmonics, since these take less power to start sounding. We added a combination of low pass and notch filters to alter the system’s frequency response in favour of the fundamental pitches. We also discovered the extent to which the efficiency and pitch of the system were dictated by the way we coupled the speaker to the end of the pipe. Our most successful experiments used a large round bung (made from a plastic bucket) fitted with a speaker and pushed into one end of the pipe. In the course of these experiments we burnt out several cheap loudspeakers and one expensive power amplifier (another victim of our “More Power Igor” bent).

Despite these teething troubles we were getting some pleasing results at quite low frequencies, so we added more length to the pipe. This provided some interesting results; counter intuitively, an increase in pipe length would often result in an increase in pitch. We had our theories for why this might be and decided the system was interesting enough to demonstrate at our first ever If Wet – a monthly sonic exploration event we run in Sam’s village hall.

If Wet
The first ever photograph of If Wet, featuring the Giant Feedback Organ test rig [by Pete Ashton]

If Wet is a place to demonstrate work in progress, a place for discussion and development of ideas. Luckily, local recorder maker Tim Cranmore had read about our first event in the local paper and was present at it. When we explained our prototype’s reluctance to resonate at the fundamental frequency Tim was quick to offer a complete explanation: for the notes we sought our bore-to-length-ratio was wrong. We had been increasing the length of our tube by adding more grain pipes of the same diameter. Each time we did this the bore became narrower as a proportion of the total length. We should have increased the pipe’s diameter as we increased its length. That is what If Wet is about! Onward.

Pull Out All The Stops

Well, not immediately. Our development of the Giant Feedback Organ had been driven in part by our aim to present it at the inaugural If Wet. That had now passed. To develop this project further we needed someone to commission an instrument based on our prototyping work. Luckily for us that is just what the team at Southbank Centre had in mind. They put out a call for instrument makers who could help them create four unique instruments, inspired by pipe organs, as part of a festival to celebrate the refurbishment of the organ in the Royal Festival Hall. We were selected, and after a couple of meetings and discussions it was agreed that we would be in charge of the very lowest notes: F0, B♭0 and C1. To put this in context: that low F is off the bottom of the range of a piano, contrabass tuba and contra-bassoon…we had our work cut out.

We needed larger diameter pipes. We knew we would save time if we could re-purpose standard pipes since everything is easier: they interlock, have tried and tested fixtures and fittings and they’re cheaper than any bespoke system. We visited some yards, spoke again with the local farmer and a few other contacts, and finally chose air ducting, supplied by the wonderful Ductmann in Bilston. The first fully-laden van trip was, um, interesting…

Pipes on van
Ducting pipes on van

With the “pipe system” sorted, what followed was a period of intense testing. We had our ups and downs; or rather they were all ups as negative results are clearly still very useful. The most interesting part of our testing for some time was the development of large “reed microphones” that we would place in the centre of the tube. These were really effective in chopping the top off the frequency response. As we do at MortonUnderwood, Sam was running around building lots of test stuff, whilst David was pondering the outcomes and suggesting the next course of action. The split isn’t as clear as that really but in broad terms that about sums up our working process.

Come the end of 2013, we were still struggling to get the pipes to go off at their fundamental frequencies. In fact we were struggling to alter the frequency of the note at all. Most odd. At one point we suspected the room effects were greater than those of the pipes, so we took them up to the village hall but that didn’t seem to alter much either. We did however have much of the system well established with custom built speaker couplings, a powerful PA amplifier, a suitable desk and filtering system, but it was clear that it wasn’t responding as you’d expect from blowing air up an organ pipe; we hadn’t yet achieved a proper resonant system.

Over the break we resolved to have a rest from thinking about the Giant Feedback Organ but there were these huge pipes nagging me. I had this urge to try going back to early mic tests, as a means of calibrating where we had got to. I started digging around and found some old boundary mics I had been given. Unexpectedly these provided some particularly low frequency results. Also, by moving them up and down the pipe I was able to recreate the early swanee-ness. Progress. I reported back to David and he investigated the specs of some of the omnidirectional boundary mics I had, assuring me these would provide better bass response. As ever, correct! I also found that, inexplicably, one brand of boundary mic provided much better results in this context than the other two I had. Who knows why but at this stage we didn’t care. We were moving in the right direction again.

Giant Feedback Organ
A view down the pipes

Our prototype was soon providing reliable results and we could use the mic position within the tube to vary the pitch to a small degree; sufficient that we could use one tube to deliver the B♭0 and C1 notes. The exact pitch of each note is determined by a number of factors: pipe length, mic position, low pass filter settings and the power used to drive each channel. This comes in very handy when tuning the organ within each new space because the size and shape of the room also has a great effect.

The interface

Our instrument was to be placed in a public space, for use by all comers. It was therefore important that its console was welcoming. It had to say “Play me!” to young and old, musician and non-musician alike. We concluded that big, bold push buttons were what was needed and we fabricated the console itself out of the same material as the pipes, so it was clear what you were controlling. This console was the only part of our instrument that the public could touch. The pipes were to be suspended high up in the space, not least to avoid small people climbing into them.

Giant Feedback Organ console

Rounding it off

This is the aspect of instrument design you forget at your peril. Even just constructing an interface that will survive abuse by children (and their parents) over a prolonged period is no easy task. We also had to consider how the pipes would be suspended, how cables would be run, how equipment would be housed, removing sharp edges, preventing stuff falling over, constructing mic brackets etc. We had two bites at this cherry with rehearsals at the Nautical School near Southbank Centre a couple of weeks before installation. Some stuff is best left until you can meet with the people responsible, and we made some changes in response to their suggestions. The result was an instrument which didn’t require a single maintenance visit.

Rehearsals and performances

While building our instruments all four makers had engaged with Pete Flood and Andy Mellon of Bellowhead and families from Lambeth who helped us design what they needed for their performances. Visiting London with the instrument for rehearsals we got an idea of the scale of things. Together the four instruments looked great, there were more members of Bellowhead, many of the children and family members we had worked with before and a choir! What a glorious racket they made. A few minor tweaks later and we were down again for the final install, followed by the public performances.

Installation – what could possibly go wrong?

We had a great weekend at the Southbank Centre for the final performances. By this point everything seemed to be working well and we could relax. In fact, we had a bit of a proud. The tunes were great, the children were a delight and the instruments seemed to do their job very nicely. Much fun was had.

Giant Feedback Organ - Southbank
The pipes in situ

Performance day – the calm before the storm

Performance day – chatting with feedback pipes in background

If Wet at Southbank Centre

As a “cherry on the top” we were asked to host a Meet The Makers event to highlight the work of all the instrument makers on this project. This was hosted in an If Wet salon style; everyone discussed their work before makers and audience visited the Clore Ballroom to try the instruments for themselves. If Wet went from Callow End village hall to the Southbank Centre in less than a year – not bad!


What’s next?

On Monday we noisily moved the Giant Feedback Organ to a warehouse space in Birmingham. During our tests we found ways to extend its usefulness both as a musical instrument and as a sound installation. This is a central project for us, so developments will continue forthwith. We are exploring all facets of this instrument: How might it sound as an extension to a traditional pipe organ? How low can we go? What can we do with the burbling thunder sounds we get when forcing the sound below the fundamental of the pipes?

We welcome enquiries from anyone wishing to explore these or other aspects of the Giant Feedback Organ!

Bye Bye
Bye bye Southbank Centre

Bye bye and thank you

Lastly, we’d like to say thank you to all involved. The Southbank Centre staff and crew have been a delight to work with, as have Bellowhead and the Lambeth families. The other makers were great too. Our suppliers have been wonderful; with special thanks to Ductmann for their expertise. Thank you, as ever, to our local farmer…who is frankly amazing! Thank you to our friends and associates for their advice and support, including those who have supported If Wet throughout. And thank you to Sam’s girlfriend for, well, putting up with us.