Music? Underwater? Really? I was both intrigued and excited by the challenge of this. This was one of those things that perhaps had the risk of being, if you’ll pardon the pun, a total wash-out. On the other hand, it had the chance of being amazing. It was amazing.

I really enjoyed working with the Danish group, “Aquasonic”, and with the small, transatlantic team they’d put together to really get to grips with all the issues of making good sounds underwater. We had a mechanical (and usually robotic) instrument maker from Brooklyn, an underwater acoustics professor from Texas, a pioneer in the development of the world’s first musical instrument that actually produces sound directly from water – the Hydraulophone, a “normal, above water”, Danish acoustician, a New York producer who usually works with the likes of Cirque du Soleil and me, the metal percussion specialist who also has some form tuning unusual instruments and figuring out general stuff to do with vibrations and acoustics.

The Aquasonic project has been going on for quite a long time, making discoveries and incremental improvements all along the way. With this new team and concentrated effort though, I think we’ve really pushed things forwards a few great leaps. Firstly, lots of skype conference calls, emails, tests, experiments and simulations. Then, for me, further underwater testing of prototype ideas in a plastic tank with a hydrophone (underwater microphone) in my workshop in Bath. Then a 9 day trip to Aarhus to install, test, tune and troubleshoot new instruments of my creation and some 3rd party instruments too.

So, Aquasonic is now 5 musicians, each with their own large custom-built aquarium – the largest ones clocking in at around 1600 litres. They play (and sing – more on that later) underwater as an ensemble. The audience gets to keep their feet on dry land – the music is picked up by hydrophones, amplified, and relayed through loudspeakers. The musicians have in-ear monitors so they can hear each other. This may be more important than you think. Visual cueing is not so easy with the strange refractive effects looking outwards from inside the big glass water-filled tanks.

The first big improvement was sourcing and using better quality hydrophones. We were all still very worried about standing wave reflections in the tanks (the wavelengths of sound in water are much longer than in air – the aquaria are very small spaces acoustically speaking) and attenuation issues, not to mention the de-tuning effect of the mass-load of the water on the instruments due to strong coupling because of close acoustic impedances. Musical instruments barely “notice” the air around them, but they really can’t ignore the water if they are in it. The second big improvement came from our acoustician – put the hydrophones right into the corners of the tanks. You get a boundary effect which naturally boosts gain and you also get a fairly nice constant overall amplitude (from summing the mics together) as you move the instruments around within the tanks. Before this breakthrough, it was looking worryingly like we would need spot hydrophones, very precisely placed, on every single instrument (and, in the percussion tank, there are 20 to 30 individual instruments). Standing wave issues, for the most part, were not actually a problem. Though we did spend a good amount of time fine-tuning the position of the 15 or so Singing Bowls to balance their timbres and resonance.

There are major issues with volume and sustain of almost all musical instruments underwater. You can forget wind instruments straight away, though Laila Skovmand and her protege Nanna Bech have mastered an inhale-exhale maintain-a-bubble-in-the-mouth underwater singing technique. Struck and plucked instruments almost all behave as dipoles and front and back sound waves cancel much more readily in the non-compressible water than they do in air. Most instruments have to be massive to have a chance or they need to have a continuing energy input – e.g. from bowing or rubbing.

Gongs work quite well – especially the tuned types, with nipples and collars. Higher overtones tend to be attenuated and pitches shift down by varying amounts. Singing Bowls work surprisingly well, especially larger ones. I did a little re-tuning work on Aquasonic’s extensive collection. Only one bowl broke as a result of the (really quite delicate and tentative) re-hammering. I found that larger Bell Plates were good too, but their aspect ratio needed to change under the water – detuning of the overtone frequencies is not linear. They drop about a fifth overall, but the higher tones drop more than the lower ones. Through the generosity of a local glass workshop (Nyholm Cantrel Glass) we had access to equipment necessary for careful tuning of both ceramic tiles and glass bowls from a custom underwater Glass Armonica – Andy Cavatorta’s Crystallophone.

I spent quite a bit of time in my own workshop trying to get Aluminium Harps (or instruments using the same principal) to work as I thought that they could be good under the water. Getting the right friction was a problem though. It still may work with a glass instrument, but time ran out there and I didn’t get to try it. As a by-product though, I came up with what I later dubbed the “SETIphone” as it rather resembles something you might use to contact little green men from outer space. Using (lacquered to mitigate rusting) rebar clamped in the middle on a frame with a cymbal as a sound radiator you can create quasi-pitched industrial sounds by striking or stridulating the bars.

There was a quest for something to perform a hi-hat function. Normal hi-hats and cymbal stacks just don’t do in water what they do in air. The cymbals are too light and there is too much suction between them. For drummers who have trouble with air-lock, you should try water-lock, it is orders of magnitude worse. We didn’t need foot pedal action, just a short, dry (but not too dry!) sound to propel beats along. We had a “bass drum” from a strategically damped Gong Ageng and a “snare” from a Darbuka (about the only actual drum that works underwater – though I did have high hopes for boo-bams). My best prototype was a cup chime with a triangle stacked on it. The evolution of this, which was more satisfactory, was a larger but still quite heavy cymbal with a triangle stacked over the cup and 6 pairs of tambourine jingles riveted around the periphery. The stacked triangle provided crunch while the jingles added hiss. Each one alone wasn’t enough but the combination was about right.

With the improvements in the hydrophone technique, cup chimes and triangles were found to be much more resonant than early tests had suggested, so we threw some more of those in as stand-alone instruments. The SETIphone actually became overwhelmingly loud and lighter beaters had to be employed!

With the new, expanded and somewhat more hi-fi sound palette, Laila is composing new material. Full length concerts will start happening in mid 2016. There were some short teaser previews at the SPOT festival in Aarhus this May. I was blown away by the video from it, even though it is still at the embryonic stage. I can’t imagine what will develop after another year.