Made the day after a gig in Manchester, this is the last of four videos of my pop-up sonic art installations I made on that trip. I spent a long time in this tunnel, and have a lot of leftover footage from some of the other cameras, this video mostly featuring footage from my gimbal device. This was only the second time I had used it, and was just about getting the hang of it.

One reason for spending a long time in the tunnel was to carry out my strategy that I settled on in Newbold of putting the devices in the water upstream and letting them drift downwards, rotating or otherwise. I don't often get the chance to put it into practice, either because I'm in my boat, for which I have not yet worked out the fundamentals of paddling, or because letting them loose in the current would send them cascading over a waterfall, and so forth. In this case there was some current (there is often very little), but the rotation of the units can counteract it, meaning they don't drift downstream very quickly.

Having started at the brick end, I soon got bored of waiting and pulled them into the rocky area, which was much more interesting. But here, the pink unit suffered a direct hit from some water falling from the ceiling and started to malfunction, so I stopped the shoot, having barely captured a few minutes in the rocky area.

I have a plan to make a much longer and less watchable ambient background video from this using all the good spare footage.

With a gig to do in Chepstow, and having to travel there from London, I had a few options for canal tunnel locations that I could plausibly visit within more-or-less the same journey. This was a good choice. Not too long, meaning there was a modest glow of useful light from either end, but long enough and wide enough for a good natural reverb. The first problem was getting everything into the water. There were some steps from the towpath down to the tunnel portal, but then a good 2" between drop from the ledge to the water. I narrowly succeed in lowering the Randomatones into the water without losing the floats. Next problem was to get into the boat without capsizing it. As you can see from the pciture that I'm still dry, I managed.

Being mid April on a not particularly busy stretch of canal, I wasn't massively surprised not to have been disturbed by any boat traffic, but felt lucky all the same to have been left to savour this fantastic shoot. Every shoot has at least one technical problem or another. On this one, despite having tested it carefully the day before, the orange (brought out of retirement for one last shoot) wouldn't connect to my WiFi, even after a reboot. Didn't matter much, I built in a workaround for that.

My one slight regret is that I had been considering setting up an underwater camera, but hadnt't brought it. Typically canal water in the UK is not worth the bother, visibility is centimetres at best. (Oddly, the water in the Limehouse Cut in London is surprisingly clear.) I tried it for the Cookley shoot, but used only footage from before I submerged the camera. On this canal the water was very clear, further evidence that the waterway is little used. So this is the second time an underwater camera might have been stunning, the first being Sapperton last November, whose water is normally completely undisturbed by boats, people, or anything.

Second of two videos under Manchester Piccadilly on the Rochdale Canal between the Dale St and Piccadilly Locks. In this one I was about to call it a day, but given it was chucking down with rain, I stayed undercover and tried out my new floating audio and video recording unit, complete with two Rode NT5 microphones and two cameras, one on top of a mast. Pretty much a failure, although all I really cared about at this stage was that it would stay upright and not capsize. I was able to use some of the video from the lower camera. The upper camera was pointing too high and basically rubbish. The audio only recorded intermittently, for a bit, before descending into complete silence. I think the battery died. When I tried it the next day I got nothing at all.

Both parts of this shoot were a disappointment. On a calm quiet day this would have been an adventurous and thrilling space, but the water was way too turbulent for me to get a decent video of it on the day I was there.

First of two videos under Manchester Piccadilly on the Rochdale Canal between the Dale St and Piccadilly Locks. This was a fantastic location, but in terms of getting a good audio recording it was spoiled by the roar of the excess canal water tumbling over the lock gates at both ends. Perhaps one day I will return to this location with some new Randomatone versions, and there will have been much less rain, so that I can get much closer to the Dale Street end, with its imposting bridge arches.

I loved the rocky fabric of this secluded spot under the A513 in Staffordshire. It's a location only a boater would know about, not that I want any boaters about when I'm making a video. Fortunately for me, at 8am on a rainy Sunday morning in March, there weren't any and I had the place to myself. Besides some slight camera issues, and general taking an eternity to get set up, this was an exemplary shoot. I got the units in the water undercover. I was expecting the water level to be much lower, but the amount of recent rain had raised it to the point I was able reach it from under the bridge. It had also given it a noticeable current, meaning once I had dragged them to the other end, they floated downstream perfectly over 10 or so graceful and sublime minutes.

Having not been able to shut the pink unit down properly at the end of yesterday's shoot, it was still playing in its previous key, whereas I had reset the blue one to play in a different key. Theoretically you might think this would result in clanging dissonance, but with only two or three notes in play at a time, the interlacing notes made for some luscious chord sequences and they sounded fantastic together.

This is the Snarestone Tunnel on the Ashby Canal in Leicestershire, where I stopped on the way up from London to a gig in Stoke-on-Trent this evening. Great location, no wind, no rain (until I emerged), no leaks, no boats, with somewhere I could park my car nearby. Minor technical issues on this one, for some reason the pink unit wouldn't start its audio processing automatically, and needed me to press the manual override button I had very cleverly added to the units a few weeks before, having wished I had one on several shoots in the past.

I was in slightly better control of my boat this time. As I sat in it, drifting on the slight current into the middle of the tunnel, I savoured this stunning sight and sound of the two units against the backdrop of the south portal, spoilt only by something pokey in my rucksack digging into my back as I sat against it.

On the way up to a gig in Manchester a few weeks ago, I stopped at this tunnel on the Grand Union Canal in Warwickshire. I had been through it on a canal boat trip in 2020, but remembered only the imposing western entrance (seen here at the beginning of the video) and nothing else about it. I didn’t remember that it had water pouring in through the roof everywhere, as was the case on the day I turned up. It had been raining up and down the country, so I assumed this was the reason. In fact the tunnel always leaks, giving rise to many flowstone formations inside. I didn’t see much of that on the day, as I did not venture in past an enormous cascade maybe 20m in from the entrance, which would have wrecked my non-waterproof devices.

Despite noisy waterfalls the other side of this lock and the one immediately upstream, on the Rochdale Canal under Manchester Piccadilly, I thought the water was just about calm enough for a Randomatones video, and even if the sound turned out to be unusable, here at least was an opportunity to test the recording. Fearful of the currents, I tethered the recording unit to the side, while it joined up with the sound-making units via a new V-shaped connecting rod setup made from thin, lightweight and very expensive aluminium L-beams. Feeling after 10 mins or so that I got quite a nice shoot out of it, I decided to stop videoing, take a couple of stills, and just enjoy the sight and sound for a few minutes, something I almost never (get to) do on a shoot, and yet which is the whole idea of this sonic art project. I managed a couple of minutes, before I realised the tether had come undone, and my fragile devices where about to get swept into the lock.

The Deansgate tunnel on the Rochdale Canal in Manchester on a wet February evening, where I had gone for a gig the following day. It was part of a generally wet February, with a lot of rain up and down the country, and a lot of that rain draining into the canal. You can see it pouring over the lock gate at the end of the tunnel. That ruled out videoing in this location, partly because of the roar of the temporary lock-gate waterfall, but mainly because of the turbulence. For a Randomatone video, I want stillness.

A couple of things have dissatisfied me about floating Randomatone video shoots in the past. One is that I've seledom been able to get a good audio recording. The floating units have onboard mics, but those are too close, and capture too much mechanical noise from propellors etc, and not enough ambient sound from the location. Another is that I've not been able to get decent close-up video of the units while still capturing the location. I can get close-up video from towpaths in tunnels, but video from one tunnel tends to look like video from any other, and I could be anywhere.

So this is an experimental third unit that I wanted to put together using only as much equipment as I had already, without spending much money. The only things I invested in were windjammers and shock-proof mounts for my two Rode NT5 microphones, and a stereo USB mixer with two phantom-powered XLR inputs. I powered the mixer from a small 9V battery via a 7805 voltage regulator I scavenged from some other old equipment I taken to bits. The video is captured via my trusty old LG G5 phone, plus a higher wide-angle view from the small action camera that also doubles as the Wifi hub. The same 5V supply can power those two devices if necessary. Sadly it seems like the G5, despite its newer USB-C connection (unusual in 2017 when I bought it) doesn't recognise the USB mixer as a stereo audio source for its video. No matter, it has its own mics, and I record the Rode NT5s on a separate Zoom digital recorder at the bottom of the float. The whole thing sits in a black plastic enclosure that came off an old car vacuum cleaner, which I thought I was only keeping for the motor. Funny how things are useful. The black enclosure exactly fits the middle of the silver swim ring.

Slowly getting on with the first new build, on my tidier-than usual work table. The Raspberry 3 model A+ and the HifiBerry are going inside a water-resistant plastic enclosure, for when the unit accidentally drifts under a cascade of water pouring down from a canal tunnel roof. Doubling up horn and waterproof speakers to try and get the most out of amp. Earlier spinning Randomatone versions had only one small horn and one small cone speaker and they were too quiet. The wooden "deck" will sit on top of the normal 24" silver float, with a short mast for coupling to another unit (I would not let these loose by themselves).

Earlier this year I started buying bits to build two new floating Randomatones. Normally when I build new Randomatones I cannibalise the old ones for the expensive parts (Raspberry Pi, HifiBerry amp). The current set of three floating ones, the blue, pink and orange units, have done very well and I have taken them out many times, and I want to keep them.

They are also pretty large, and I want some smaller ones with which I can be more mobile. At one time I had two small spinning versions that could both fit into my rucksack, meaning I could get them to places in London on my bike. They were too small to be visually that interesting within a location, and I could not get them loud enough without distorting the speakers. The current floating ones are loud enough and big enough, but a bit too big to carry around easily. I want something in between. And because I'm favouring watery locations such as canal tunnels, there is the frequent risk of rain falling on them, so I want the new units to be water-resisant.

The picture shows some of the parts for one new Randomatone. I'm sticking with the same model Rasberry Pi for now. There are other varieties of small Single Board Computer I could try, but being able to stick on the HifiBerry amp hat to it makes me inclined to stick with the Raspberry Pi for now. New ones were impossible to find last year thanks to the global chip shortage, and when I finally managed to bag two more, the price had doubled.

Each new device will have two plastic horn speakers for one channel, and two waterproof plastic cone speakers on the other (or I might try one of each per channel). Doubling up the speakers means they will shift more air, and wired in parallel will get the most power out of the amp in terms of impedance matching. Between the speakers in the picture is a waterproof case. I've not bothered with one of these before, but I think it's time. The blue item below the case is a new battery. This is 14.8V 5.2Ah lithimn ion battery, more powerful than the 12V lead acid batteries I've been using, and a lot lighter. Below that is a different variety of propellor motor (with an H-bridge in its plastic wrapping). The previous ones worked OK initially but soon started to sieze up either with rust or other dirt. Possibly lack of maintenance on my part, but I'm going for a different brand here just in case it's an improvement.

The Randomatones in their creepiest location yet. I'm thinking that for the next several outings I'll be sticking to canals that are still in use, with tunnels you can actually walk through on a path, before I venture into many more locations like this. But the Randomatones looked and sounded stunning in here.

Stupidly, my failure to ensure a certain battery was properly charged meant that I lost wifi connection to the units fairly early on, which meant I could not direct them back towards my position in the shallow water of the entrance, meaning I had to stray into the tunnel to get them. I do not recommend you do this. The tunnel owners have not asked me to say this, I'm just relating my own experience that the tunnel floor is muddy, I nearly got stuck in it a few times, and had I fallen over and got my hands stuck too, that could have been the end of yours truly. So I repeat, if you fancy striding in yourself, I do not recommend you do.

The immediate consequence was that wading in up to my thighs created turbulence of the surface, disturbing the stillness of the water that I like so much, and if I could expect from any location, it would be here. Also I created mud clouds, spoiling the otherwise pristine clarity of the water. On the plus side, wading in meant I got some good video looking out into the daylight, wishing I was standing there. Apart from that, from the gothic entrance, into the undisturbed brick time-capsule of this abandoned water conduit, this could have been their finest setting.

The tunnel's wikipedia page suggests the Cotswolds Canal Trust at one time conducted boat tours into this tunnel, presumably from the other end near Coates where the tunnel casing is considered safe (I entered though the northern Daneway portal, which the CCT consider not safe). They don't advertise them, and perhaps never did any, and have instead only carried out private surveys. But supposing they did, maybe a little sonic art installation like this would enhance the trip.

After a summer and autumn off (unusually spent playing actual music with real people, or perhaps real music with actual people), and with a winter-time trip to Wales to come back from, I stopped at this fabulous and faintly scary location in the Cotswolds, the Sapperton Tunnel. I had avoided this kind of location in the past partly out of fear, and partly because I was not yet satisfied I could make a video in complete darkness. That is still somewhat true, but with some additional lights on the connecting rod, powered by a nice new small but powerful 9V rechargable battery, I felt I was just about ready to try this location, given that I would be passing by.

From pictures online, I surmised the water in the tunnel would be several inches deep, and I might need a new pair of Wellington boots, so I went to buy some before setting out. The one size the shop had none of was mine. No matter, when I waded into the tunnel, the water came up to the top of my thighs.

I'd been through here on a canal boat trip a couple of summers ago. As the family in front of us went through on their boat, the younger ones started whooping and singing, making the most of the massive reverb in the tunnel. Perfect Randomatones territory.

When I returned one Sunday morning a couple of weeks ago, the tunnel was every bit as special as I remembered it. There was almost no wind, and the most of the time no boats, so the water was like a mirror. One technical issue got in the way. The forward/reverse propellor motor on the blue unit had siezed. I was prepared for this, with pliers and oil, and I managed to make it go, but only with it emitting a loud screech as it turned. I thought the din might not be so bad underwater, but the muffled squegging was still audible. I left it in most of the video soundtrack, for honesty.

After a while I got fed up with the noise and turned all the motors off, whereupon I was treated to a sublime and mesmerising sound and light show as they drifted very slowly downstream in the slight current. I left mostly elated, except for the small part of me that wished I had shot the whole thing that way.

Having a journey to the West Midlands to make, I set off a couple of hours early on this Sunday morning and stopped on the way at Newbold-on-Avon, to spend as long as I could videoing in the Newbold Tunnel between passing boat and swan traffic. This is me approaching the eastern portal through the mud, through Spring has definitely arrived at this point, and the peace and quiet of the canal is decorated with an abundance of birdsong.

It struck me as I was videoing in the tunnel that I had possibly never heard birdsong with a huge reverb applied to it. We almost always here it in the open air with no reverberation, likewise when used as a sound effect, or featuring in a field (literally) recording. However, stand a little way into a 189m brick-lined tunnel sunk into a wooded hill, and you witness plenty of this semi-natural phenomenon.

A couple of hundred metres west of the previous Park Rd location is this beautiful tunnel under Lisson Grove. Leaving the bustle of the main road, down a winding path, you descend to a different world. This tunnel is one of a kind in London. London has two other longer tunnels, on this same canal, but you cannot walk through them, while this one is relatively short (48m) and has a towpath with railings. It can only be accessed during the day, as its section of the towpath lies within a private mooring that is closed off to the public overnight.

By day, the Regents Canal path is a well-trodden walking route, so there were a few spectators on this shoot. I did a not very good job of keeping out of their way, and stayed as long as I could, until the tether got caught up in one of the propellors (that’s happened twice now). By chance that was all the time I had anyway, between the to-and-fro of a sightseeing narrowboat. You can see it passing downstream as I blow up one of the floats, and just as I got the devices out of the water, it returned.

An early winter evening outing on the Regents Canal just west of Regents Park, under the Bakerloo Line and Marylebone railway bridges. This was the first time I used a tether, having wished I had one for the Bow Flyover shoot, and had not got the hang of it, spoiling many shots by flapping the string up and down. One day I will trust the piloting abilities of the blue unit, which has two propellors for forward/reverse and rotational movement (the pink unit has one propellor, for rotation only). However, on the evening, the blue unit motors where playing up, or possibly not running fast enough.

Also on this one I had problems with floats, and had to blow up three before I had a couple that I thought I could trust. I was mistaken, as the air nozzle cover of the blue unit float popped out early on, causing it to slowly deflate through the video.

The Regents Canal doesn't have many good bridges in the Hackney area, when your definition of good is wide with a noticeably long natural reverb. This one is on the Hertford Union Canal, which runs along the south of Victoria Park and connects the Regents Canal with the navigable River Lea. This isn't great either, being short, but the acoustic is noticeably good, possibly a result of its square-ish concrete construction, with a kind of enclosure provided by the upstream lock gate. An evening shoot might work here.

Where the Mimmshall brook crosses under the M25 in Hertfordshire, alongside a footpath connecting Wash Lane on the north side with Dancers Lane on the south, is this tunnel, a basic concrete building block construction that has little going for it even by way of graffiti, except that it is brightly lit, seemingly for the benefit of almost nobody. It also seems to be routinely flooded, which is my main interest comes in.

For this episode, I waded into the freezing water and swished the orange and pink units around in quite a current, hence the use of the tether (something I wish had used in the last video). Depending on the camera, there are some spectacular scenes in this video, especially the long geometry of the concrete segments and their joins.

The Regents Canal to the east of Camden Lock has several promising bridges with nice acoustics. This one under Camden St is probably the best, but there are at least six decent candidates before you get to the Islington Tunnel, leading to the tempting possibility of taking out an inflatable boat one afternoon and covering as many as the batteries will manage.

Back to this location for a shoot after coming across it a year ago (19 Feb 2022). When I went there last February it was flooded. When I went there last week it was flooded, as I had the feeling it would be. Not for nothing is this path called Wash Lane. The first thing I discovered was that the Randomatones can float in only a few inches of water, something I could have known or at least measured, but was not that bothered about given the target location has been canals. The second revelation was that people use this passageway, and I saw two people where I expected to encounter none. Certain aspects did not surprise me, such as how cold the water was.

Normally I like graffiti in a concrete tunnel like this, but on the riverside section of wall there was nothing, and little on the path side either, leaving the starkly lit bare concrete, which was appealing in its own way.

At the end of an evening getting the pink and blue devices ready for a trip out tommorrow, to two locations if I have time, and the ailing car manages it.

Fifth floating Randomatones video, this one on the River Lea under Stratford High St and the Bow Flyover. First appearance of the pink unit with its white horn speaker, to replace the grey one which was distorting. The motors were not behaving themselves on this trip, so the units tended to stick to the edge of the path where the wind blew them. I am thinking a tether might be useful next time.

Even so this video captures some of the beauty of this huge covered area. I'm thinking of a return trip in a boat in a month or so, keen to capture the silky water again before it gets completely covered in duckweed, as it tends to in the summer.

And under a Bakerloo Line bridge, next to Park Rd on the Regents Canal just west of Regents Park in London. Those trains are faster in this spot and more frequent, so there was a lot of noise here. And I had problems with floats. Otherwise I was videoing for almost 25 mins, a record.

After a couple of troublesome trips to the waterside this year, time for some quality time with the soldering iron and some amateur woodworking, to build the little device on the right in the picture, with which I can test the floating Randomatone motors. I checked them the other way two of the three would not turn (the blue unit has two motors, the pink has one). They had seized, probably with dried river muck, and needing freeing with pliers. Good to discover that on location before they get into the water.

The bundle of cable to the left off the same production line is for use at home and lets me power two units together from the same 12V supply.

Unlikely I will make a video here, though I quite like this bridge. The main reason not to is the wildlife on either side, that will probably not appreciate my mechanical swans. Also the reed stems, which have been cut back for the winter, would risk tearing the floats if they drifted too close. Also this seems quite an exposed spot, and had quite a breeze when I visited. The again, maybe one day I should embrace the breeze and use it somehow, rather than it be an obstacle.

The 16th Randomatones video and the fourth to feature floating units, I made this one the day after the Cookley Tunnel video in June 2022. I got the camera on the connecting rod working, and even though it's a cheap camera, the view down the tunnel from it is superb.

This is on the Regents Canal just west of Park Road, where the Marylebone railway tracks cross over the canal. The acoustic is not that special, as the bridge comprises several sections with many gaps between, so it's not really an enclosure with a nice echo, and when trains pass they are noisy. However, there is good shelter from wind, and there is practically zero current, so the water has a glassy stillness. On top of all that, the fluorescent lighting is stunning, making this a perfect spot for an early evening installation.

A summer shoot in Cookley, Warwickshire. The canal tunnel there is short and narrow, with a close acoustic. It's also unlit, giving me an excuse to put some underwater lights on the units. These create an eerie glow in the murky water. I tried an underwater camera, but visibility was zero.

Back out for a Randomatones shoot after more than six months away (working on semi-related electronic drum-triggered randomness), to a concrete-lined waterway under Stratford High St and the Bow Flyover in East London. The acoustic is cavernous, and the curved walkway is lit at water level, and although not to everyone's taste, there is some colourful graffiti along the wall. The downside is that there tends to be a significant draft down-river, in the same direction as the current, meaning controlling two flimsy floats was bound to be precarious. In the end I didn't have the courage to let then units drift away, despite having spent some development time on the propellor controls, as I wasn't confident they had enough power against the wind and the current. But it was a good test of my two-camera setup on the connecting rods.

This tunnel carries the navigable river Lea under Statford High St and the Bow Flyover. Coming here in winter is ideal because the water is clear of duckweed. In the summer the surface can be caked in the stuff. Anything other than a light breeze down river could be a problem. But with its flat concrete ceiling and walls, the acoustic here is nice.

And sure enough, there was sudden flooding in the subway at South Woodford tube and I wasn't ready. In fact this drained away quickly. When I arrived I could see the water marks where it had been half a metre higher, still not enough to cover the shopping trolley. And the water was a mud soup, with all kinds of rubbish in it. Not that rubbish in the water has stopped me before.

A couple of years ago my wife, my son and I had a week-long canal holiday on the Warwickshire Ring. Most of this was countryside, but part of it went through the eastern edge of Birmingham. The environment was a bit on the gritty side, and the waterways were a shockingly polluted soup of all kinds of household waste. But in general I found the canal architecture hugely appealing, especially this fine example just south of the Tyburn Road (A38) in Erdington, where the canal passes under a derelict factory that once made electric furnaces.

As we drifted slowly underneath, I felt had to come back to this place for some artistic reason or other. I was so enthralled with it, I crashed the boat into the bridge at the other end.

Two years later, on my way back from a band rehearsal in Stoke-on-Trent with two floating Randomatones in the car, I returned to this place to record them moving about in the water at random, and playing their randomised glow-in-the-dark concert of varispeed arpeggios to the empty resonant space of this covered section of canal.

Putting together the third floating unit. A simpler construction than the other two, this one uses the other grey horn speaker and has a single motor for rotation. Note the new detachable battery unit, with a serial plug for easy connection now that it has the battery terminals, the motor connection and an underwater light, which you can see minus a covering.

First showing of the floating Randomatones after months of development, taking my exploration of the acoustics of enclosed waterways to another level - the water level. Conditions for this shoot were pretty good, the water was glassy smooth, and there seemed to be very little breeze. Then I got the units in the water, and after first nearly disappearing down the overflow, they blew off upstream under the bridge, where I wanted them, but then kept going. I had not had a chance to properly get used to the remote controls for the propellor onboard the blue unit, nor did it seem powerful enough to counter the upstream wind. I thought I was going to lose them on their first outing.

I really like the way they looked and sounded though. The sound featured the new arpeggiation I had been working on (trivial compared with having to fit remote-controllable propellors) and was fantastic under the bridge. Visually the units were striking in their vibrant colours, and the searchlight glare of the LED spot lights on each unit played beautifully over the clean brickwork. When pointing at the camera they were a bit intense, but for now my plan is to improve and increase the rotation of the units, so that the glare is only ever fleeting.

In all, a decent first trip out and very promising.

Another exploration of the acoustics of enclosed waterways, though not so enclosed as the canal tunnel in the previous outing. This one made for a slightly better video as there was more light, and the silky smoothness of the water is clearly apparent here. This is the smaller of the two Itchens north of Southampton as it flows under the roaring M27.

Feeling that the small units were being dwarfed by these large spaces, I brought a new larger orange unit with a more powerful horn speaker that sounded very smooth at home. I had another large pink one in the works but it was not ready in time for this trip. I stopped working it completely after making this video, as I knew all I wanted to do next in locations like this was to get units floating in the water.

Not actually floating yet (they will sit on inflatable swimming rings in the water), but lined up and getting ready to go for the first floating shoot happening soon.

This massive railway bridge crosses the Regents Canal just north of St Pancras station in London. The canal is quite wide here, and there is plenty of noise from trains passing overhead, but the acoustic is good. This could work with the spinning units, but would be another good incentive to get floating units working.

Up in Kidderminster for a gig, with some time to the souncheck I went to check out this location where the Saffordshire and Worcestershire Canal passes under the A456. The concrete enclosure gives this a place a great acoustic. But in order to come here I need floating units.

Another empty orange shell, this time for a second floating unit. I hope to take both of them out next month. Trying out a slightly different design to the blue one, with a panel of large holes that will accommodate four upcyled 3" speakers.

Another blue unit that will eventually float (buoyancy device not shown). This uses one of two kinds of 30W horn speakers I've been trying, again with the back casing and the 100V line transformer removed. Still quite a bit of development to go on this, as it will have a steerable propellor, which needs a remote control mechanism.

Made on a rainy Sunday morning before I was due at a midday rehearsal near Tardebigge. I took a canal trip a couple of summers ago, part of which was a day on a section of the Birmingham network. I didn't pass through this stretch of waterway, but the trip definitely left an impression, though not entirely a good one at the time.

The combination of water, enclosed spaces with rich acoustics, and simple ambient music is a serene one for me, and one I intend to explore much more deeply. I live in London, which has a canal network, but nothing like Birmingham, whose centuries-old waterway architecture seems largely untouched despite modern redevelopments all around it. And unlike London, it has tunnels you can walk through.

Also I very much prefer ducks and geese to pigeons.

Soon I will start building one of these. The two most recent video shoots (editing in progress) have been waterside, and much as I enjoy these locations, I remember the very first Randomtones video in the flooded subway near my house, and want very much to do something similar with floating units rather than only being able to suspend them from exactly the right kind of railings.

I had been hoping for music with neither. In the event, the pigeons provided an interesting few seconds of rotating filth, as I placed a camera on the underside of the blue unit to capture a whirling view of the unit and the ground below, in which their droppings produced a kind of blurry rotating starscape (watch from 0:57 for 10 seconds to see what I mean).

Passers-by came and went in step with train arrivals, and many turned their heads.

In general this was a fine location, a handsome Victorian arch providing a pedestrian walkway next to Pudding Mill Lane station, with the recent modern concrete Crossrail addition for contrast. Relatively quiet, but perhaps too vast for the small units. The larger horns would have made more of a sonic impact.

The finished version of what was an empty painted shell a couple of days ago. This one has the new white horn speaker, meaning I can play it louder in larger spaces without distorting. Also it has a camera, which I may or may not use, as video tends not to be all that usable when the camera is spinning. The main issue with this unit is that it doesn't fit in the rucksack.

With a back-of-an-envelope sketch of how to set up a Darlington pair transistor arrangement, plus a couple of resistors for LEDs, I take a few minutes carelessly soldering up a motor driver board, and then get the wiring wrong.

Only single-direction capability here. A reversible polarity setup would require an H-bridge arrangement. For a while I had no plans to implement this, as the varying speeds of the motors was enough to suggest rotational chaos. This was empahsised for me when one day I made the red unit rotate in the opposite direction (for a shoot last month). I found with the units rotating counter to each other, the variations in their speed were unnoticeable.

Several coats of paint later, via a white base, then pink, red and orange fluorescent acrylics.

Brush strokes are clearly visible but I think this will do, I am ready to build it now. Seen here with the 12V 5Ah battery in place. I was assumed it would need some kind of restrainer, but the battery is such a tight fit, I don't know if I'll ever get it out again. Pity, that was the idea. The current two read and blue rotating units would need to be taken to bits to get their batteries out.

An almost perfect spot for railings-based or floating Randomatones.

Admittedly this location is not in a perfect state. The floodwater is muddy, which I don't like. And although I would have no problem wading in here, as it's probably only 15-20cm deep, I would create waves which would spoil the stillness if I were to use floating units. Having incorrect shoes at the time of visiting, I didn't go in to see how quiet it was, but outside, the M25 above was incredibly noisy. Nothing to stop me making a decent video with just the direct sound from the units, but it would be nice to hear how they sound in that acoustic, which given this is a concrete casing, should be very good. Also it's lit, which is a bonus. Sadly no graffiti though.

This is a location I considered some time ago, and though I knew it could not possibly compete with the Woolwich Foot Tunnel, I set up here anyway purely to tick it off the list. It turned out to be a great setting.

The acoustic was flattering and the colours were surprising, with the ochre brickwork almost aglow. Most appealing when I look back at the video was the reflective concrete ceiling. Just as people preoccupied with videoing a situation scarcely notice what's around them, I barely noticed it at the time.

I had been working on the sounds and by this point had introduced occasional octave sweeps. I did wonder whether these might be a little extreme and disturbing to the many depot workers entering and exiting their site, perhaps worrying them that one of their buildings might be on fire. In the end some last minute scaling down of the effect was worthwhile. The sound on the shoot was excellent, though it comes across less well and was generally too quiet in the recording, compared to the roaring of trains passing overhead, and the depot workers unloading a massive digger off a low-loader nearby.

If you're wondering how that activity did not appear in my usual walk-towards and walk-away shots, it's because I did those on the previous day. I did all the setup, switched on, and found that the units did not turn. I had broken something while fiddling with the octave sweeps.

Two new carcasses under construction. These are little more than battery cases with supports for large speakers at either end. The battery will sit on its side, now that I have had the courage to do this with lead-acid gel batteries (you wouldn't do this with a traditional top-up-able car battery). This potentiall saves height, although each will feature one of the large new horns, which outsize any savings made in the vertical dimension.

On the theme of gem locations, they don't get much better than this.

Besides the sound being a bit muddy (it was much clearer listening to it in the tunnel), and the autofocus on my phone not handling spinning objects in low light conditions, this latest video is a terrific demo of how these units sound in a reverberant acoustic. It also demonstrates how chronic noise pollution can be ameliorated, here forming an integral part of an ambient music piece.

I was very anxious about this shoot. CCTV camera pods every 50 paces, drunks yelling from one end to the other, generally being in the way of people and fast cyclists. Least of all was that the alarm, which I had recorded and set the Randomatones to play in their key, would have stopped or changed to something in the wrong key. My worst fear was one of the supports coming off and the unit falling on someone's head. That’s assuming I got the supports the right length. Too short and I would not be able to hook onto the pipes, too long and people would be hitting their heads on them.

Nothing of the kind went wrong. The supports were perfect. The units sounded stunning and fitted perfectly with the alarm that was still sounding 10 days after I last heard it. For six blissful minutes I wondered around videoing from various angles thinking "this is beautiful."

Not everything went smoothly. I had tried and tested small suction cups to stick on the tiled walls for mouting my camera (phone) and my Zoom audio recorder. On the day, the cups immediately fell off, and that was without anything attached to them, luckily. Most of the still shots I did with my phone on a gooseneck stand clamped to my cycling helmet.

Sometimes location scouting turns up a real gem of a candidate, such as this, the Spital Brook tunnel under the A10 near Hoddesdon.

The A10 is a dual carriageway at this point, but the banks are very wide, making this tunnel both long and surprisingly quiet. All surfaces are concrete, including the footpath, meaning the acoustic in the middle is excellent. The railings are perfect for hanging Randomatones from, and the water right now looks only a couple of inches deep, allowing paddling around with a tripod if desired. Even the walls have graffiti, though it's hard to see as there is no lighting inside. I will need to adorn each of the rotating units with another 10W or so of LED lighting.

I may not use this one, as it is a car journey from where I live (South Woodford) and I believe there is a similar specimen nearer to home that I aim to check out soon.

One of two new larger horns I will be trying, next to the current blue unit for scale. The small horns on the current units are only 15W, which is too small for the 20W amp, causing them to distort. The larger white one is 30W, and as you can see, somewhat enormous. That will be the end of pacing over to shoots with just a rucksack

I thought I had made a mistake here, as when the new horns arrived they were clearly 100V line devices, which would have been no use. Luckily, take the back off and all you find inside is a transformer to convert the ordinary low impedance magnet/coil driver to 100V line. Simply remove this transformer and the speaker is good to go. It's also at least 0.5Kg lighter.

Another video prompting me to reflect on what sort of setting works for the Randomatones and what I want them to do.

I'm still a sucker for graffiti and enclosed outdoor spaces with some kind of acoustic. This location, on the river Roding just north of the Redbridge roundabout in East London, is all of that, and had exactly the look I wanted. But it was far too noisy to make a meaningful video demonstrating the sonic delights of the Randomatones. Of course it would be noisy, I should have known that. The time I first considered it as a location was summer 2020, when possibly fewer people were rushing up and down the North Circular and it was quieter. I don't remember.

Anyway I'm reasonably pleased with the look of this video, if the sound does have to come direct from the units, and not from microphones that just picked up traffic noise. I think I need bigger units. Once again these looked tiny in their vast concrete arena. But they are still fun to capture close-up, and I risk boring even myself if I follow through with plans for several more videos like this.

Some very important props. I never throw old bits of wood away, nor paints that are still vaguely liquid. Forthcoming videos involving the new rotating devices each need their own pair of supports to fit the location. The black ones bottom-left were the railing fixings for the Roding video, to be released in a day or two. The two white ones on the left have just done their work on a video shot this afternoon.

The grey and purple ones are for the next couple of planned shoots, though I may build some bigger units before then. The purple ones are almost certainly the wrong colour, but I'll see.

I've been meaning to make a video here for a while (see 09 Sep 2020), though my original idea was to have units floating in the river and rotated by the current. I am still a little way off making a good floating unit, but at least these ones rotate.

Despite the witty title implying sources of weird noises, the music from these is tame compared to some earlier versions (eg this).

One day I will get a good audio recording of the space, but this was another poor effort, as my microphones were too close to the units and picked up the motor noise more than the music. I knew this was a risk, and spent some time tuning the motors so that each of the discrete speeds the motors ran was in tune and in key with the notes from the Randomatones. The motors are driven from a pulse width modulation (PWM) output from the Raspberry Pi (via a couple of power transistors), and I achieved the tuning by selecting the appropriate width and pulse of the PWM. This sounded convincing indoors. Outside, all you can hear is a tuneless whining buzz like an electric shaver.

One of the things that attracted me to this location was the ledge on either side of the thoroughfare on which I could set up the units without being in the way of passers-by. Having only ever biked along it, I did not realise until I got there for the video that the ledge was above my head height. I insist on showing you how bad I was at climbing up onto it. I must have done so at least 12 times during the shoot. Sadly practice made no perfection, instead I got worse and worse at it.

I took the red prototype and a second blue unit to a railway bridge in the Walthamstow Marshes earlier today to make the next Randomatones video. The acoustic was reasonable, though I was mainly drawn to this location because it is a quiet railway underpass rather than a noise road bridge. Also it had a handy ledge for me to climb up on and attach the units without a step ladder. Though I was there early in the morning, this passage was a surprisingly busy thoroughfare for dogwalkers, joggers and cyclists. Not one seemed remotely bothered that I was attaching mysterious devices to the underside of their bridge.

Testing the rotation of both units on the stairs before going out to make a video of them somewhere out in the wild. The test was worth it, as I had set the voltages on the blue motor too low, and it didn't turn.

Before assembly, sometimes the empty frames look appealing just by themselves. I love these acrylic fluourescent paints, glowing even in the cloudy daylight. This one has been carefully measured and constructed around the battery, with an arm each side to support a speaker. Then I take it apart again for painting inside and out, somewhat unnecessarily, as the battery will cover up some of the painted surface.

Back after several months away with a prototype hanging spinning Randomatone. This one has a 40 RPM geared motor whose speed is varied using one of the PWM ports on the Rasperry Pi. The motor mechanism issues its own clearly audible whine, but by using some combination of PWM voltage and frequency, I am wondering if I could tune the motor to the Randomatone notes. I want variable speed, so that several together will all rotate differently and chaotically, but I would be happy with them shifting between discrete speeds rather than varying continuously as now.

Also note the introduction of a cheap plastic horn speaker. Compared to the other more hi-fi cardboard cone speaker, its sound quality is poor, but the squawky mid-range of the horn does suit some of the rougher waveforms the unit generates. It's also lighter and more weatherproof than the card-cone speaker. Not that I plan to hang these from trees or lamp posts just yet.

I will probably rethink the decorative red and blue LEDs. It looks like a kind of weird megaphone, but when I watch the thing spinning I think of a siren on a police car or fire engine. A Sirenatone. (I doubt I will call it that for long.)

A video in a foot tunnel under the Central Line near Snaresbrook. A long way from the dual carriageways near some of the previous locations, this tunnel is comparatively quiet with a beautiful acoustic. The only constant sound is the water coursing from the surrounding soil into the drains. Earlier in the year those drains blocked, and the whole thing flooded. I was hoping it would stay that way so that I could make a video in it with some floating Randomatones, but before I even had time to build one, all the water was pumped out and has yet to reappear. I hope one day it does, but I probably won't be ready then either.

Stage one of assembling some new units for placement on a sloping surface in a large area hopefully later this month. In the spirit of randomness, no two legs of these three tripods are of equal length. Will use the same Randomatone units, probably at near maximum volume, with some generally larger speakers. I have not figured out where the battery will go yet, though one idea might be to hang it from the apex, allowing it to be upright (which for lead acid batteries is best) no matter the orientation of the structure on the slope.

A lockdown exercise megawalk recently took me though this footpath underpass beneath the Liverpool St main line. Even on a cloudy day the colourful walls seemed to glow, and despite an open air section in the middle it had a reasonable acoustic. So a couple of days later I stuffed two Randomatones into my rucksack and biked over there for a quick lunchtime installation.

Having done all the shots in the last video pointing at the Randomatones, in this one I hardly did any, I was so taken by the colours and geometry of this walkway. Unlike in the previous video, the positioning of the units along the ceiling line goes some way towards explaining their shape. I had planned to put one device under each tunnel section, but the ceiling was higher in the north tunnel and I found I could not reach it. At least this time I had the volume good and loud, and the units properly sang through the walkway. A lot of the ambient audio in this video was picked up by the mic on each unit.

After making a video last week of three brightly coloured Randomatones in a dreary tunnel under the North Circular, the first piece of feedback I received was "Fantastic! Did you leave them there?" No way, I thought, there's £100 of gear on each one at least! But then I thought, if this is supposed to be art, I should be aiming to do exactly that. What could I change that would make me comfortable leaving something there for, say, a day?

Leaving expendable stuff, is what. No Raspberry Pi/HifiBerry units, no £20 speakers (though £20 for a speaker is very cheap) and no brand new batteries. Whereupon, various bits of old junk I had in the study or the shed came to mind. I have no recollection what piece of kit this amp came from, but electronics with crazy printed circuit boards like that I reckon are from the 1970s. So, naturally, it all still worked. I soldered up some power leads where I thought the 12V supply should go, plus two speakers from an old TV (15W each, surprisingly), and a 3.5mm stereo jack to the input. Then dug out an old unloved mp3 player and plugged in. Even with those puny speakers it was pretty loud, though I know loudness in the home is on a different scale to loudness in the outdoors. This will not be a true randomatone, as it will have to play a recording. But as the real units are not yet interactive, I can load an hour of sounds on an mp3 to play in a loop, and the effect will be the same. Random ambient music for dog walkers.

Not that I am a conservation activist, but the title refers to the gouging of an enormous channel though the remains of Epping Forest (actually this section is called Walthamstow Forest) in the late 1960s. Where there were once oak trees there are now seven lanes of motorway, and former paths though the forest are now carried over the road, or under it, as in this tunnel at the western end. There is very little beauty in this perfunctory subway, but it does have a great acoustic, if you can tune out the traffic noise. Sadly I could not, as even the three units in concert were nowhere near loud enough, but by now I have made them capture recordings of their output, allowing me to cheat with some echo treatments at home.

Making another video, this time with three Randomatones made to attach to railings in a foot tunnel under the A406 just west of South Woodford. Again I had the volume a bit quiet and could not make it louder, having had problems making the units connect automatically to portable Wifi dongle (or any Wifi they already knew about).

Visually they were somewhat dwarfed in the vast space, something to bear in mind for planned A406 tunnel #3. Also the yellow fluorescent hue is a let-down. While the red and orange blend seamlessly, the yellow is too much of a gradation.

The acoustic in this tunnel was excellent, and had the units been loud enough, and the traffic above quiet enough, the weird sounds that were still coming from the units since their Halloween update sounded entrancing in the space. As it was, the rumble of the vehicles hurtling past overhead was strong enough to make the railings vibrate, as I discovered when I tried to attach my camera.

Going ahead with some painting for the new frames that I postponed when constructing the uprights (in main image above). I used to make wooden assemblies for my variouts bits of electronic drum components and paint them all matt black so they would not be noticeable on stage. Nowadays I'm a bit of a sucker for fluorescent colours for exactly the opposite reason. Loving the Daler Rowney range, thick and creamy and a single coat is almost enough. I used a cheap one for the orange and you can see it needs daubing on at least two more layers.

A Randomatone in a pumpkin.

Not a placement I intend to pursue, but a bit of fun that I couldn't resist, between taking the floating unit to bits and reassembling it in another setup. Also an excuse to get started on some simple pitch shifting of samples, of which I intend to make much more use later. Purely for the spooks I used a chromatic note generation scheme instead of a conventional minor or major key, and stuck to sine waves. It turned out no more scary than a 1950s B-moving where the aliens have landed, in fact I prefer it. The notes arrive too slowly to clash, and there is a sense of freedom to it.

On the soundtrack, the bangs in the background are genuine, and I have little idea where they came from. But like serendipitous moments that happen when improvising music, they work brilliantly as an impromptu percussion accompaniment to the eerie space-calls from the two bug-eye speakers.

Some new woodwork for three smaller units that should see some action in a few locations around South Woodford over the coming weeks. Unlike previous constructions these are more-or-less uniform, except one of them will make space for a WiFi router. White undercoats and fluorescent overcoats to follow, prior to assembly. Also each one needs a hook.

A video of a floating Randomatone making its way through a flooded foot tunnel.

My original aim was to capture the tunnel acoustic. But in the rush to video something before the water drained away, I was ill-prepared with mics, the unit was too quiet and there was too much traffic noise.

Instead, what came out of this opportune shoot was a unique perspective on two semi-submerged murals of tunnel graffiti that I would normally never look at, at least not while looking where I was going. The wide-angle camera gets further away than the eye ordinarily can, and its view close to the waterline as it makes its way through the tunnel is striking. While I’m not generally a fan of spray-painting Victorian brickwork in fluorescent colours, in an ugly featureless concrete people-conduit like this, I begin to see the graffiti as modern example of the way people have been expressing themselves on walls for millennia, like 21st century cave paintings.

A short demonstration of the first three Randomatones positioned strategically on the stairs up to my study. Strategically in this context is another word for in the way. The Randomatone audio in this is all from the phone mic, plus the zoom recorder you can just see attached to the middle unit. I did no overdubbing afterwards.

Never one to miss an opportunity within reach, I spent the day trying to fit a small 12V pump to the diamond unit so that it would rotate when lowered into the water. After just about getting it working, I put on my nastiest old trainers and carried the whole thing plus my inflated inner tube down to the subway. Just as I was starting, a cyclist appeared, wondering if he could get through. I warned him I had tried yesterday and it had ended badly. He asked, is that a science experiment? No, I replied, more like an art experiment. He stayed to watch me wade a little way into the tunnel with the floating Randomatone, trying not to drop my phone in the water.

I learned a few things doing this: 1) The sound was not nearly loud enough to resonate in the tunnel acoustic. The volume was not set to maximum, even then I'm wondering if it would have been enough. 2) I'm glad I used polypropylene speakers, even if they were a bit small, as they caught a lot of rain. 3) Amazingly the electronics survived, despite being completely exposed, though I will not do this again without putting them in a plastic enclosure. 4) The water felt moderately warm after I'd been in it for a few minutes.

Cycling to the drum room, I took a long meandering route via my favourite nearby locations for possible floating Randomatone action, keen to see the state they were in after 2 inches of rain in the last 24 hrs. Biggest surprise was the south tunnel under the Waterworks Roundabout, knee deep in water, as I found out when I tried to cycle through it. Later I wondered whether I should go straight ahead and build a randomatone frame for the half of one of 25l bottles. Then I remembered I had bought an inner tube weeks ago exactly for this purpose, and could probably get the single diamond one up and running faster.

Trying all three units for the first time, after a making a remote control via wifi that can adjust the volume or shut down all three units together. Batteries lasted a good few hours despite their age, though the unit with the Model B Raspberry Pi (which consumes more power than the Model A+ versions on the other units) ran down much quicker and died. Maybe I'll need the massive golf-buggy 20Ah batteries next time, as not only are those more beefy, they are new.

The sound was fairly lush, though there were some technical issues with the audio not ramping up or panning properly, for which I have a plan B. Even just on the stairs there wasn't a lot of spacial definition, ie sounds that discernably come from one place or another. I realise now that the nature of the sounds, which ramp up and slowly back down in volume, probably do not lend themselves to directionality, whereas more percussive sounds might. Something to try later.

As a listening experience it was soothing and not at all irksome even after having it playing round the house for many hours. After turning it all off, I still heard the sounds playing in my head, like seeing residual auras of colour when the lights go out. Just as unsingable, too.

These from the car mending work shop on the industrial estate where my drum practice room is. They were about to chuck them out. At 25 litres, each would provide easily the buoyancy I need for a Randomatone, even cut in half into miniature barges. These are by no means ideal, as I really want something round, or with a high degree of rotational symmetry, as I want to rotate them in the water while keeping them tethered.

Test assembly already weighing in excess of 4Kg. The plan was to attach large bottles perpendicularly to the three joists just before they converge at the base. Utter failure. The flimsy 2l milk bottles buckled as soon as they hit the water and the centre of gravity was far too high. I should probably be learning some fluid mechanics if I really want a go at this. My first thought was to seat the unit in an inner tube of a car tyre. I have one ready to try. However, I am still clinging to the idea of using bottles, this time facing downwards and running along the lower joists rather than perpendicular to them. Plus I have a fallback plan if I really want to make floating Randomatones, but it will involve a different frame.

After the nth coat of white paint. The plan was next to daub them each with a fluourescent pigment, but right now I'm enjoing them just in plain white. Up close, with my imperfect woodwork and rough sanding, they look like miniature adobe towers. I'm thinking I will wire them all up as they are and make a first video somewhere, before considering colours.

Three units taking shape now. First task for each one is to position the speakers. The middle-sized one is the prototype, so I had already done this. The other two are similar, but each unit has a different combination of speaker sizes for individuality. The plan is to position the multiple units in separate parts of the room, but I actually quite like the way these units look clustered together. It makes me thing the speaker positioning should be random, rather than regular and predictable as they are here. Next task is to take the speakers off, put other bits of wood on for mounting the electronics later, then sand and paint in bright colours. Because why not.

Back to the dry land idea, having enjoyed listening to one of these, time to start putting together more of them. Target is three for now, for which I will see if I can arrange some kind of showing in London. Maybe get a video together first. It strikes me the audio should be a field recording. It will be almost impossible to capture the ambient sound distribution from having three (nevermind several) of these positioned around a room, and a normal stereo recording is going to sound too perfect an impression of the wrong thing. One idea I had is to mount a couple of tiny mics onto each unit and let each make its own room/field recording from its perspective, then mix those in the stereo image depending on where the camera is pointing.

This looks like a nice spot for it. The acoustics under the first bridge are sweet, and the traffic noise from above might even complement the sounds. What to call it though - Water Music For Randomatones? Randomaquatones? Also somehow I have to get these things to float. My heaviest 12V batteries are 5.5Kg. That's going to need a big tyre.

An eventful week of blowing up a Raspberry Pi and an amp. Tried a new smaller RPi (model A+) and found it had some glitches, but these could be reproduced simply by adjusting the system volume, so I'm not confident about the analogue output. Needing a replacement amp as well I went for a HifiBerry Pi "hat", which is entirely digital and will thus bypass all the RPi audio bits which I think are the issue. Also, brilliantly, it takes 12V but will do the step down to 5V itself for the RPi. This will save me having to have an extra unit with wiring issues. Tried it all out after the necessary config changes in the RPi to tell it where its audio has to go. Not only does everything work, the audio is basically clean. Needs a volume control though, without a keybaord or a mouse. Hmm! In a totally unrelated flight of consciousness, I have begun pursuing the crazy idea of making a set of these units that will float. This would be the basic chassis, and one way of making it float might be to use the inner tube of a car tyre. So I've ordered one. I might work on this frame idea a bit more. I'm pleased with my elementary woodworking skills to have made this item, which at least looks like it fits together.

A long walk to the drum practice room for exercise, made even longer on discovering a strategic footway under the Central Line at Snaresbrook was flooded. This little-used subway has a terrific acoustic and would otherwise be a prime candidate for recording some Randomatones. Sigh.

The prototype again, reconstructed with only three vertical posts, as I realised the fourth was unnecessary and in the way. Tried the sound generator, essentially everything works, with some issues. Audio playback has glitches, and there is a lot of interference noise. One issue might be the 12V-5V converter, as I've heard this kind of noise before when combining audio signals from things with different switch mode PSUs. Anyway I tried a USB audio interface just to rule out the RPi onboard DAC. Slightly quieter. Reduced noise significantly by not using 12v-5v stepdown, instead powering the RPi from a regular mains PSU. Got noise at all running it from two separate batteries. Joining the battery grounds made a load of noise reappear. Joining the +ves also made noise appear. Tried a different 12V-5V converter from the car, same result.

Assembled prototype. You can just see that behind the circuit boards is a massive 12V 20Ah battery, the kind you find in a mobility scooter. This powers the Raspberry Pi via a step-down to 5V, and a 2x20W amp, currently driving two cheap speakers from Halfords. I've been preparing the software for this for some time now and had it working on a regular linux machine, and have tried it out on the RPi by itself over Wifi, not in this assembly yet.