Hurd-E Gurd-E

MUSICAL Instrument, Synthesizer, MIDI Controller

Spirng 2018

Introduction

The Hurd-E Gurd-E is a Moog Werkstatt powered electronic musical instrument. The Hurd-E Gurd-E takes the metaphor of the Hurdy Gurdy, a stringed instrument that produces sound by a hand crank-turned, rosined wheel rubbing against the strings. It was first built during 2018 Moog Hackathon and later modified into an MIDI controller controlling a FM patch powered by Max/MSP.

Mapping Notes for Final Version:

1. The spinning speed of hand crank wheel of Hurd-E Gurd-E controls the volume of VCA

2. The membrane sensor and pressure sensor are controlling the frequency of the carrier and frequency of the modulator

3. The position of the magnet on the circle in the front of the Gurd-E controls the pitch of drone

4. The big red button acts like a kill switch

5. The lid opening position controls cut off frequency of the VCF (open and close lid metaphor as some acoustic instruments)

Here is the performance with Hurd-E Gurd-E on 13th GTCMT Learning Machine Concert:

Development Log:

Version 1.0 (Moog Hackathon)

The original Hurd-E Gurd-E was built during 2018 Moog Hackathon with Xingyuan(Alan) Zhu and Yongliang He. This version of Hurd-E Gurd-E is powered by Moog Werkstatt. The Hurd-E Gurd-E takes the metaphor of the Hurdy Gurdy, a stringed instrument that produces sound by a hand crank-turned, rosined wheel rubbing against the strings. Two features that make the Gurdy an unique instrument are: the hand crank wheel that bowing the string to make sounds; multiple drone strings, which give a constant pitch accompaniment to the melody (similar to bagpipes.) There are two challenges during the hackathon: first is how to smoothly map the rpm of the spinning wheel the synthesizer; the second is Werkstatt is a monophonic synthesizer but we need a second VCO to make the drone.

During the hackathon, we came up solution like following:

For detecting the rpm of the spinning wheel, we attached magnets on the wheel and put a hall effect sensor on the bottom. Then we use a Arduino Uno to process the pulse we get from the hall sensors when the wheel is spinning. Depend on the frequency of the pulses, we will calculate the rpm of the spinning wheel and output corresponding voltages to VCF to controlling the filter cut off frequency. When the spinning wheel gets faster, the cutoff frequency of the filter will getting into human audible range and thus function as a volume control for the Gurd-E. The wobbling of the rpm due to the slight player uneven spinning will have interesting “tremolo” like effect on the volume. Thus, I like this mapping very much as it is intuitive for the player and creates interesting natural sound effects.

For the drone, we tune the LFO (Low frequency Oscillator) to human audible frequency so that we can have the second oscillator as drone. The problem since everything of the instrument (except the rpm detection) are analog, you have to hold the voltage in order to sustain/keep the same parameter for the input of Werkstatt. For the drone part, the challenge is you have to hold the membrane to hold one note. We uses a circular membrane sensor as pitch control of the drone. The solution we came up with the holding note issue is we put a circular metal plate in the back of the membrane so that when we stick a magnet on the metal plate, we can hold it at the position and thus hold the note for as long as the player want.

Other mappings we did are: we have a long membrane sensor to control the VCO frequency (pitch); a long pressure sensor underneath the membrane sensor to controlling the VCA (volume), Thus when the user push the membrane like pushing the string on string instruments, the Gurd-E will start to make sounds with corresponding pitch. We also have a arcade style button for a kill switch to make percussive sounds (which try to achieve some percussive sounds.)

Unfortunately, the pressure sensor broke during the hackathon and we have to use a square FSR as our volume/onset controls of the Gurd-E.

The following is a presentation video of Hurd-E Gurd-E Version 1.0 during the hackathon. The sound design at this time takes the metaphor of Circular Saw and thus it sounds like sawing the wood (very industrial music feeling.)

Version 2.0 (MIDI Controller)

Later, I took out the Werkstatt and make it into a MIDI Controller. In this version , the sound design is done with MAX/MSP. I changed some of the mapping and at this point: rpm of the wheel is mapped to VCA, and since the synthesis method behind the Gurd-E now is FM synthesis, the membrane sensor and pressure sensor are controlling the frequency of the carrier and frequency of the modulator. Following is demo video for version 2.0:

Version 3.0 (Painted)

After version 2.0, I decided to follow my original aesthetics — mecha-future style design (which I wanted to do in the very beginning but due to the limited time during the hackathon, I didn’t have time to do so.) I painted the the Gurd-E and later Yongliang played this instrument along with my modular synths during GTCMT’s listening machine concert:

Version 4.0 (Standalone)

This is the final form the Hurd-E Gurd-E. During the summer of 2018 when I was doing my internship, I make the Gurd-E into a standalone instrument so that I can play it with my favorite guitar pedals. Here is the video of Version 4.0 which Takumi Ogata helped me shooted with his modular synths. Special thanks to Takumi for his kind advice and supports during all the development stages of the Hurd-E Gurd-E!