a unique drone machine with 2 oscillators, 2 LFOs, and a very nasty resonant filter

Now available in a variety of colors!

Contact me if you are interested in a custom build.

bent Taalmala

Taalmala and Sunadamala 1

Taalmala and Sunadamala 3

 *** UPDATE 5/23:  The auction has ended ***

The new owner is electronic artist Sin:Ned from Shatin, Hong Kong.

How I came up with the WaveFucker is a long story. The condensed version goes like this: I’ve been considering different algorithms to generate interesting drum patterns. I thought about having a FIFO shift register with data feeding into it, and a clock oscillator driving it. A scanner resamples data in the FIFO at a different rate… so the output is sort of a jittery rendition of the input. Then it dawned on me that I was using the basic architecture of a digital pitch shifter, but really lo-fi.

To understand this concept, imagine that you are flying a helicopter above a highway with cars. Imagine the cars are equally spaced and you are looking down on them. You can fly the helicopter at whatever speed you want to relative to the cars below. You’re looking straight down. Every time a car crosses your view, tap your finger. So, if you are hovering still above the highway, you are tapping at the same speed as the cars (zero pitch shift). If you are flying faster than the cars, you are tapping slower than the actual rate the cars are entering the highway; that is a down pitch shift… fly backwards, and that’s an up shift.

I modeled this in Reaktor and it makes interesting polyrhythms and syncopation when run at rhythm speed. I cranked it up to audio speed and added a guitar input. As a guitar effect, its a really fuzzy and completely inaccurate pitch-shifter, meaning it doesnt shift notes by a constant interval; the interval depends on the pitch you play. Somewhat like a ring modulator crossed with a bit crusher. Ascending scales can become descending scales and vice versa. All very fuzzy and clipped sounding.

Anyhow, since I’d rather play with hardware than software, I designed the Reaktor patch as something that could be translated to hardware based on 4000-series CMOS logic. It turns out it can be done with only six IC’s! I sketched out a schematic and laid out a protoboard using Eagle. About 8 hours of assembly and the hardware version was up and running on a 9V battery.

My hardware WaveFucker has these controls:

• fuzz gain; high-low gain button
• “freq” oscillator w/ high-low range button (50Hz - 14kHz)
• “spectrum” oscillator w/ high-low range button (50Hz - 14kHz)
• scan forward/reverse button
• scan freeze button
• filter drive knob
• filter frequency knob
• filter LPF/BPF button
• fuzz / wavefucker blend
• feedback mode button

The fuzz circuit is adapted from Craig Anderton’s Tube Sound Fuzz, and the filter is adapted from the PAiA Syndrum circuit. I borrowed the basic idea of the blend control from a MiniMoog schematic; its an H-pad with the middle resistor replaced by a potentiometer; the potentiometer’s wiper goes to ground, and the output resistors go to the inverting input of an op-amp. In the MiniMoog, this is behind the OSC3-Noise blender knob.

Here are some recordings of the hardware version in Feedback mode; its oscillating with no outside input. Its playing through a small Fender amp with the reverb turned up.

wavefucker feedback #0

wavefucker feedback #1

Visit this page for more sounds of the WaveFucker.

In feedback mode, all of the controls are interactive and it gives a surprising range of sounds with bizzare harmonic structure. The results are quite similar to the Reaktor patch but hold some nice surprises and a more organic tone. Some of the sounds remind me of the bizzare trashed-out organ noises in the beginning of Facelift by Soft Machine… BTW, if you know what Mike Ratledge did to the organ to make it sound like that, please let me know!

I haven’t gotten around to recording the WaveFucker as a guitar effect but I will post that in the future.

For those who are interested, you can download WaveFucker as a Reaktor patch. You should be able to use it as a VST if you have Reaktor installed: WaveFucker for Reaktor. The main difference is the implementation of a short delay in the feedback loop. The hardware version has no delay. The cool thing about the delay is that it gives the WaveFucker a pitch memory. Play a guitar note into it, and (properly adjusted) once you let off the note, the pitch is remembered and continues to play indefinitely until you play the next note. Very weird!

I opened up the projector and did some research on the chips inside… I was able to find datasheets for the A-D and D-A converter chips and targeted them in the hunt for interesting visual effects. By inspecting the densely-populated SMT main board I gained some insight into the flow of video data in the projector. All of the inputs are analog video of different formats. The analog RGB signals are routed through A-D converters, and once digitzed, the data is held in registers for processing by a VLSI circuit that presumably re-formats the resolution and scan rate to accomodate the projector’s optics. From there the digitized video is converted back to analog via A-D converters (one for each color red, green, and blue), and hits the analog LCD drive circuitry.

To safely probe the various (mis)-connections I wanted to make, I wired up a 1k resistor and a thin wire. The resistor limits current flow and prevented damage as I made various connections. In the end I came up with six bends that were unique, and installed three toggles and a rotary switch on the front panel. These bends created color-shifting effects, lo-fi pixelization, and ghosting… not too interesting on their own, but when combined with a live camera feedback loop, I saw some rather interesting imagery. Focusing the camera on the projected image created the classic feedback tunnel effect, and when augmented by the bends I had wired, the tunnel was transformed into a beautiful fractal-like effect.

Due to a mishap, I accidentally blew up something in the blue channel’s drive circuitry so my projector only does red and green now. This occurred in a cavalier moment when I probed the circuit without a 1k safety resistor in the jumper wire… should have known better.

Unfortunately I did not have the chance to record or photograph the output seriously. However, I did run into a nice blogger named Stef Lewandowski, who interviewed me while I was showing off the projector at Dorkbot. You can visit his blog to hear his interview with me:

http://www.steflewandowski.com/?p=363

Austin Dorkbot veterans BleepLabs and ArcAttack showed off some killer hardware at the event as well. A CBS Morning News camera crew was present and it appeared they covered the entire event thoroughly. The story hasn’t appeared on their website yet, but I will keep checking here to see if and when it is published.

The tracks on the disc play different pitched notes, arranged low to high from the inside track to the outside. I’ve made two discs so far. One has six tracks and plays notes from a scale in just intonation. The second disc, which is heard in this recording, has ten tracks, and plays the 8th thru 17th tones from the harmonic series. The ten pitches cover just over an octave; it is an 8-tone scale, but not equal tempered. Here are the pitches on the disc relative to the fundamental, which would be heard three octaves below the lowest pitch on the disc. If that makes any sense - it is overtone music.

• Track 1: 8th - three 8ves
• Track 2: 9th - three 8ves + maj 2nd
• Track 3: 10th - three 8ves + maj 3rd
• Track 4: 11th - three 8ves + flat dim 5th
• Track 5: 12th - three 8ves + perf 5th
• Track 6: 13th - three 8ves + sharp min 6th
• Track 7: 14th - three 8ves + flat min 7th
• Track 8: 15th - three 8ves + maj 7th
• Track 9: 16th - four 8ves
• Track 10: 17th - four 8ves + min 2nd

The disc is made of transparent material with black markings. If you shine light through it while it spins, the light intensity is modulated because the disc chops the beam. And if you shine flashing LEDs through it and catch the light with a pickup system, and it starts making music.

photosequencer

In this recording I’m playing the disc by holding a special LED flasher over the disc and moving it in patterns while aiming it at the pickup. The flasher has three LEDs that blink in synchronization at different frequency ratios. (Its actually part of an analog synth I’m building, but it turns out to be a nice source of blinking LEDs for this purpose!) Very small gestures control the polyrhythmic melody sequences. Its challenging to play, and I can see several ways to improve the flasher to make it more playable and expressive. I also need to find the cause of that obnoxious clicking sound.

I’m using Alpha 16mm pots with DPDT push-pull switching, to minimize the control layout. Most of the knobs can be pulled/pushed to switch functions. With a total of 9 knobs, the synth offers two oscillators, two LFO’s, and a really nasty VCF. LFO1 is an analog variable-shape oscillator, and LFO2 is a pulse waveform that auto-synchronizes to LFO1 at a ratio of 2x, 4x, 8x, or 16x. Both LFOs can be routed to the filter.

18 minute drone

It’s plugged straight into a Fender Princeton Chorus.

I’ve finally had some time to stay home and build some new hardware. I spent last week messing with a very cool circuit described on the PAiA website. This started out as a drum oscillator. It was going to make cheesy boops and beeps like a synth bongo or your grandma’s Lowrey organ. However, I tweaked it a little and found that this circuit’s alter-ego is a super-nasty resonant filter.

So I designed a super compact synth around it:

• 2 oscillators (triangle / square wave) and blend control
• LFO 1 - variable slope and shape
• LFO 2 - multiplies LFO1 tempo by 2, 4, 8, or 16
• super nasty resonant filter (BPF / LPF), modulation from LFO1 and LFO2
• external audio input to filter
• volume control

You may notice it lacks any VCA or ADSR envelope generator. This isn’t about playing notes, it is about one everlasting resonating drone tone, singing through a rhythmically modulated filter.

I designed it with cheap parts that are all in current production. I intend to fabricate PCBs and design an enclosure… then I want to sell you one.

Today I picked up where I left off. I spent the day updating the high voltage regulator section (no more overheating, yay!) and designing a tremolo circuit. Originally I intended to leave out the tremolo in favor of a tone control, but enough folks have pointed out to me since then that tremolo is an essential part of the classic Wurly sound. So I tweaked the tone control circuit a little, and added a vactrol-based tremolo oscillator. It turned out sounding pretty cool; the tremolo effect seems to be accompanied by a slight filter modulation… an appealing sound.

I’ve left the circuit running for several hours as a burn-in period and it appears stable.

I have also decided to re-name the project WurlyBrain… its just easier to say than Electric Piano Amplifier 200.

At this point I need to prepare a revised PCB layout and send it off to pcbex.com. I’ll write another post as soon as I have units ready for production. In the meantime, let me know if you are interested.