Here’s a quick video to demonstrate:

One of these devices was built to order for a DJ who plays a lot of gigs in a lot of different environments, and from my own experience using these light-controlled instruments in live settings I know it can get a bit tricky dealing with the many and varied light sources which are often out of your control.

That’s the reason for having a potentiometer in line with the LDR, so the LDR can be quickly tuned to the conditions.

Also if the light is so bad the LDR cant be used at all, it can simply be switched off and the pot used on its own.

Schematic (click for full size):

Notes:

• To build the first device in the video, omit C1, R1, R2, S4, and the 555 chip.
• The two schmidt triggers (the triangles on the right) are on a 40106 chip.
• The LDR (photoresistor) has a resistance of 0.5M ohm (dark) to 8.4K (light).

Let me know how you get on building either of these designs, or any other light-controlled instruments. Or anything else for that matter. Good luck!

The Idioelectric project is one part of an attempt to explore ways of performing with multiple instruments as a solo musician, and to experiment with looping in what I hope will be a less obvious than usual fashion.

The music presented here was recorded live over 7 days at Draw Inc Gallery in Hamilton as part of the 2011 Fringe Festival. I spent a couple of hours a day in the gallery space – as a living part of an exhibition – experimenting with the process of layering loops of percussion instruments, home-made electronic devices, and environmental sounds captured on the fly.

The results are presented here as Idioelectric, two album’s worth of instrumental music now available for download or as a two-CD set. (The CDs come with 3 bonus tracks, and schematics of the devices used to make the music are individually hand-drawn on each disc. If you’re in Hamilton you can check them out at Artifice on Collingwood Street, this week only.)

recording process

The instruments and devices were set up on a table in the gallery with the electronic devices plugged directly into the mixing desk and a single microphone for the acoustic percussion instruments. Other microphones were placed further off in the gallery space to record the room reverb and ambience, and outside on the footpath to capture the sounds of the city going by. There was a bit of construction going on just up the street which was helpful.

I used Mobius do the looping, it’s a great piece of software that works like a loop pedal.

[Note: Not everyone reading this is familiar with recording tech & terminology, so if you know how loops work then this paragraph is not for you, ok?
A loop is just a piece of recorded sound that can be played back repeatedly and seamlessly; originally a literal "loop" of audiotape, now most commonly a digital equivalent. In the context of loop pedals & software it works like this: You press a button to start recording and you make some sort of sound. Press the button again to stop recording and what you just recorded immediately starts playing back over and over as a loop. You can then repeat this process and keep adding layers of loops which all play back in unison. It's a simple idea but it takes a bit of practice to do it smoothly and seamlessly and keep everything in time.]

The Mobius software allows for eight simultaneous loops and has fully customisable MIDI implementation, so I used the assignable knobs on my Akai LPD8 (conveniently there are eight) as a mixer for the loop channels.

Using the submix bus on the desk allowed me to have any number of things happening live at any one time, and send any one or any combination of them to the looping software.

The entire output of the mixing desk – including the loop playback, the indoor and outdoor microphones, and whatever else was playing – was recorded live in stereo onto Minidisc. This is the source recording, and just over seven hours of audio was recorded in total.

editing process

In editing this project down from seven hours I followed two basic principles:

1. Subtractive edits only. So lots has been taken away but nothing has been added to the source recording.
2. The sequence of events within each piece should remain unaltered. So (A)(B)(C)(D)(E) might become (A)(B)(C)(E) but never (B)(A)(C)(E)

Following those two principles helped to preserve the integrity of the recordings and ensure that the project remain live in orientation and not become a studio-based creature.

I’ve also tried not to clean the recordings up too much as the glitches and accidents are all part of this way of making music.

equipment used

• Sinewave/Squarewave generator
  
• Circuit-bent and otherwise toy pianos
  
• Alesis HR16-b drum machine
  
• Ring modulator
  
• Optical theremin
  
• Atari Punk Console
  
• THE DESTROYER
  
• LFO-controlled squarewave siren
  
• LFO clock (555)
  
• Bandpass filter
  
• Mutant radio synth
  
• Ribbon-controlled squarewave monosynth
  
• Sovtek Big Muff
  
• Delay/distortion/pitch-modulation pedal built by Sean Kerrigan
  
• Plus a pile of percussion instruments including sticks, wooden tongue drum, wood block, agogo bell, oven timer bell, other bells and shakers, a few mics and a ten-channel mixing desk.

I learned a lot on this project that I hope to incorporate into the various other ongoing projects I’m involved in. I particularly enjoyed blurring the edges between real-time sounds and looped sounds – listening back I’m not always entirely sure which are which – and finding ways to blend acoustic and electronic elements rather than juxtapose them, both tonally and in terms of playing style.

I hope you enjoy it as much as I did.

oh ps I stole the name from my friend Chris, I hope he doesn’t mind but it seemed appropriate (and dude, you’ve been sitting on that word for years )

At the opening I played some live experimental electro, and Silke from bFM sang and played ukulele. This is a short clip of some of the music I played, with images of some of the artworks for those who missed seeing them in the flesh. Below the video, some detail about the instruments used.

• The pulsing rhythm is the nand machine I built a few weeks ago, video here.
• In places, the nand is driving THE DESTROYER to make squelchy rhythmic sounds along with it.
• The constant sweeping harmonic squarewave sound is played manually on the Good Will Audio Generator.
• The feedback echo explosion sound are made by manipulating a Boss DM-2 analogue delay pedal.
• The helicopter sweeps and other sounds are made manually with a homemade LFO device.

You can see/read about more of Sean’s work here: http://artiwon.blogspot.com/ and less often here: http://artyone.blogtown.co.nz/

• Tuesday July 12th, 5:30pm
• Pierre Peeters Gallery, Habitat Courtyard, 251 Parnell Rd
• The facebook event page is here

I’ll be bringing lots of noise and lots of toys, and I might even have to bring my newest toy of all:

Regular reader Jarrod requested I start with “THE DESTROYER” as featured in this post (and named by AceMcWicked), so here ’tis:

click for full size

(ps I’m a total noob at drawing schematics so please let me know where I’m doing it wrong, e.g. I don’t know how to represent a vactrol so I just put a shaded box around the relevant bits for now, ok?)

So what’s happening here?

As I kinda explained in the video on the other post, this machine takes an audio signal from anywhere (I use a sub out/control room out/headphone out from my mixer depending what I don’t need at the time) and amplifies it enough so that the changing velocity of the signal causes a big LED to pulse in time with whatever you’re sending it (rhythmic things work well but anything with an attack works.) The pulsing light from the LED is converted into resistance by an LDR, and this pulsing resistance controls the pitch of an oscillator which is outputting a fat-ass squarewave.

Another way of saying that: It goes “pew pew pew” like a sci-fi ray gun.

Hear it in action

THE DESTROYER has so far been used on one finished recording, my remix of NSU’s “Broken Mirror”. It kicks in at about 24 seconds into this preview. In this instance I fed it back into itself which makes it go a bit mental, but around 57 seconds in it calms down a bit when I apply the decay control. Overall, this example is way more random and squally than usual but it gives an idea of some of the ways it can be used.

Ingredients:

• R1: 1K resistor, protects the LEDs
• R2: LDR (light dependent resistor) glued to D2 (see note 1)
• R3: 50K potentiometer, acts as a sort of envelope decay control
• D1: 3mm LED, optional (but handy) visual indicator
• D2: 10mm LED, glued to R2 (see note 1)
• T1: NPN transistor, I used a 2N3904. Amplifies the incoming audio signal.
• IC1: 40106 hex schmitt trigger, generates the output audio signal
• C1: 10uf electrolytic capacitor, blocks DC noise.
• C2 & C3: Capacitors, values to taste. (see note 3)
• S1: SPDT switch between C2 & C3
• S2: SPST switch to bring R3 in & out of the circuit
• J1: Audio input jack
• J2: Audio output jack

Notes & important stuff:

1. D2 & R3 are combined to make a vactrol. First, use a file to (almost) completely remove the round end of the LED. Next, use a drop of superglue to fix the newly filed flat end onto the face of the LDR. Finally, use heatshrink or lots of dark electrical tape to wrap them in a lightproof cocoon. You may need to paint out the back end of the LED. The aim is that when the LED is off, no light at all from any source should reach the face of the LDR.
2. Apparently all unused odd numbered pins on IC1 should be connected and grounded. I haven’t actually noticed this making any difference, but it might.
3. The values of capacitors C1 & C2 define the frequency range of the output signal. Choose two (or more) capacitors of different values and switch between them (S1) to give the option of high/low pitch ranges. Larger capacitor values give a lower pitch range, start with something around 1uf. If you don’t want or need this option you can replace that entire limb with one capacitor to ground.
4. R3 is a kind of envelope decay. It affects whether the output signal is cut off short with every pulse or left to carry on downwards until the next pulse. If you don’t want this option you can omit R3 and S2 entirely (but don’t, it’s pretty cool).
5. Also the small LED D1 doesn’t do anything to the audio but it mirrors what’s happening inside the vactrol i.e. it shows you when an input signal is present, which can be pretty handy.
6. All grounds are connected to 0v

Doh!

I forgot to draw in a switch to turn it on and off. Just imagine one, right at the top, just below the “+9v”

Also, the part of the circuit built around the 40106 chip is based on Tim Escobedo’s “synthstick” oscillator (you’ll have to google it, his own site disappeared a couple of years ago). My friend Sean showed me how to build it and I use it as the sound-generating portion of a lot of circuits. It makes big fat squarewaves.

In the next electronics oriented post we’ll have a look at my version of the “synthstick” ribbon controller and have a closer look at that oscillator.

Leave a comment here if I’ve forgotten anything else (or for any other reason), and good luck.

Light Dependent Resistors (LDRs) are really, really cool. Wikipedia has a proper explanation of how they work, but the short version is that the amount of resistance changes depending on how much light hits the face: more light = less resistance i.e. more current can pass through.

Over the weekend I finished off this little device and I’m quite pleased with it. It takes a line-level audio signal and amplifies it enough to power a big LED which pulses in time with the music. The pulsing light then drives an LDR which controls the pitch of a squarewave oscillator. Squeak wap bwowowow.

Just like this:

It has immediately earned a place in my new live rig and will be coming with me to Boardies & Bikinis on Waitangi weekend. Now it just needs a name. What do we call it?

Been building a new rig to make live shows much easier, with all my instruments and gadgets one one table. Developing live sets which don’t involve any computers is saving a bit of space both mentally and physically. I’ve been adapting this old DJ roadcase to my requirements:

The turntable wells make for good storage:

Tested it at a party and it’s about right size-wise. Gets it’s first big outing at Boardies & Bikinis, a 24 hour festival on Waitangi weekend. More about that shortly.

Been building a few new instruments as well, more about those shortly too.

Back soon.

A totally sweet metal folding table for small instruments;

a pair of totally sweet Atari 520STs (one for parts);

a totally sweet horse-racing record;

and a totally sweet road case.

That’s why I like the tip.

A quick video (about a minute and a half) that I made last night, playing around with a real-time looping program called Mobius.

Instruments in order of appearance:

• oscillator with LFO
• shaker
• HR16-B drum machine
• “Animal Band” toy keyboard
• oscillator with LFO

AJ on harp. Me on loops & echoes & Stylophone (thanks Silence7!) Dharma Dog on BVs. Percussion added later.

download mp3