Archive for February, 2013


Sounds of Nature with the SoundSpa

After finishing the Black Widow, Mk II, I had some fun using natural sounds with it – rain, birds singing, that kind of thing.  The final feature I had added to it was the ability for it to play automatically, which, though not quite as good as manipulating the samples with the Flight Controller throttle and joystick, would allow the Black Widow to keep operating, leaving the hands free to play other instruments at the same time.

While I was thinking about natural sounds, I came across an interesting-looking device called the SoundSpa, which is designed to soothe you to sleep with sounds of nature, including rainforest, ocean, rain, waterfall and ‘summer night’.  This sounded like a good candidate for some circuit-bending!


These machines do appear on eBay from time to time, and I was very fortunate to get one there for three or four pounds, including a handy mains adapter.  I hadn’t really done any circuit-bending, except for my work with Stylophones – like the Alien and the Hedgehog – but I described that as modification, in the sense that I knew what kind of circuit I was dealing with, and I knew more or less what I wanted to do with it.  The art of circuit-bending is, by tradition and by its very nature, more experimental.

As it happened, just at this moment, I came across an ad for a circuit-bending workshop, which I decided to attend.  So the story of the creation of the BentSoundSpa is also the story of my day at the wonderful Music Hackspace in Cremer Street, London.


[Edit: the Music Hackspace has now moved from this location.  Hopefully the link above is still working, so you can find out more about where it is and what people do there].

The workshop was organised by Susanna Garcia and run by Tasos Stamou.  Tasos has created some great music, partly using circuit-bent instruments; you can read about him and hear some examples of his music on his website: and some examples of the circuit-bent instruments he uses here:

There were about a dozen of us taking part, and enough musical toys to go round.  I took the SoundSpa along and worked on that.  First we were encouraged to start our devices playing, take leads with crocodile clips and find connections which produced effects that were, well, interesting, unexpected, dramatic . . . all of which we did. There were glitches, repeats, jumps and crashes  – but the devices seemed surprisingly resilient: when they crashed, it was just a matter of taking a battery out for a moment, putting it back, and everything would be working again.

The workshop was designed to be suitable for complete newcomers – which several of us were – so we were deliberately encouraged not to speculate on what the parts of the circuits were for, and proceed by exploration.


Nothing very exciting was produced by the SoundSpa until we looked specifically at making pitch changes, dabbing at resistors with a damp finger.  Having found the right one, we cut it from the board and replaced it with a potentiometer.  A range of values was provided, so we could pick the most suitable, and soldering irons were available to replace the crocodile clips when we were happy with our choices.

I found a very high value, 2.2M, which took the pitch of the sounds right down to almost standstill.  The only problem with taking the pitch up high was – just as I had experienced with the Stylophones – the resistance was so low the device crashed, so a small resistor was needed to stop this happening.  I calculated this would be around 10k.  On the day, I found a value high enough to prevent crashing, and when I got home I replaced this with a 10k preset, setting it just high enough to keep the device running when the potentiometer was at maximum.


After this picture was taken I decided to add a second, smaller potentiometer – 100k – in series with the large one as a kind of ‘fine-tune’ control.  This has a much larger effect at higher pitches when the resistance is low on the bigger one.

Then, to finish, we went down to the workshop, drilled holes for the potentiometers and added a 3.5mm output socket which would cut out the speaker when plugged in.


I considered replacing the original on-off switch/volume control since it was a bit dodgy – as was the one on Tasos’s example, one of several of his instruments which he brought in to show us – but it works OK with a little persuasion.


Obviously, the effects available from it depend on the wide pitch and speed variations available.  Like the Black Widow, the addition of a variable filter such as the StyloSim or the Active Low-pass Filter would add to its versatility.  I haven’t used it properly yet, but I’ll post a sound file as soon as I have one.


February 2013

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