Motivation

I have build my first synthesizer in the late 70’s. And I am playing Shakuhachi for seven years now. Time to bring both worlds together. Here we go.

The aim of this project is to provide shakuhachi players with the means to control an analogue synthesizer simultaneously with playing the shakuhachi, without affecting the playability of the flute.

So far it consists of three main modules: the pitch-to-voltage converter, the envelope follower and the “E-Shak”. The pitch-to-voltage converter derives a voltage from the pitch played on the shakuhachi. This is used primarily to control the pitch of the VCO (which is the initial generator of waves in the synthesizer). The envelope follower provides a voltage which follows the volume of the shakuhachi, together with gate and trigger signals. These are used mainly in conjunction with the synthesizer’s VCA (which is responsible for the dynamics of the synthesizer’s signal). The “E-Shak” is an exoskeleton attached to the shakuhachi with crepe tape. It is equipped with an accelerometer with three axes and with three switches. This module provides three control voltages according to the movement of the shakuhachi, and three additional on/off switches. The usage is only limited by the player’s imagination.

Shakuhachi 2 Synth project: Block diagram

Shakuhachi 2 Synth project: Block diagram

In the block diagram you can see the basic structure of the project. The microphone signal goes to the “Shak 2 Pulse” converter and the envelope follower (ENV). The Shak 2 Pulse converter is a band pass filter followed by a zero crossing detection with adjustable threshold. The output is a pulse train with the same frequency (pitch). This pulse train is converted to a voltage according to the pitch. The output voltage is available in V/Hz and V/Oct format. The envelope follower generates the gate (+5V), the trigger (+5V/20ms) and a voltage following the amplitude of the microphone signal. The “E-Shak” is an exoskeleton equipped with a three axis accelerometer and three touch sensitive switches. With the interface you can adjust the gain and the inclination of the accelerometer signal. It provides three gate signal (+5V) as well.

Specs and Features

Sitelist

Current state

S2S Current state

S2S - Modules

S2S Shak to pulse filter

Shakuhachi 2 pulse filter

Shak 2 Pulse filter

Top

Current state: Version 1.0.1 published

This is the front end to the pitch 2 voltage converter for my Shakuhachi 2 Synth project. The incoming signal from the microphone is bandpass filtered and a pulse train is derived from the signal.

S2S Pitch to voltage converter

Pitch to Voltage converter

Pitch 2 Voltage converter

Top

Current state: Version 1.2.0 published.

Here is the pitch 2 voltage converter for my Shakuhachi 2 Synth project. It is based on an article in Electronotes EN#84 p5-p9 from Robert Iodice. It consist of some control logic and a 12bit DA converter. I have found a fault in the control logic and simplified the DA converter. The original only had a V/Hz output, so I added a V/Oct output..

The circuitry takes a pulsetrain and converts it to a voltage according to the frequency of the pulsetrain.

The circuit has the advantage of sampling very quickly (only two pulses required) and holding indefinitely.

S2S E-Shack Interface

E-Shack Interface

E-Shack Interface

Top

Current state: Version 0.9.5 --- Next: Version 1.0.1 To be published

Here is the interface for my "E-Shak". The input comes from an exoskeleton attached to a Shakuhachi. It is connected to the interface with a 10 wire ribbon cable. The exoskeleton is used as addition to the pitch 2 voltage converter and the ENV follower. Inputs are three voltages from a three axis accelerometer (x, y, z) and three touch sensitive switches (Gate 1, 2, 3). The output range foe x, y, z is adjustable in gain and volume. This gives a wide variability in usage. The three gates are 5 V. The state is indicated with LED.

Condensed Version

Envelope Follower

Top

Current state: Version xxx To be published

tbd

NGF - Modules

Envelope follower

Evelope Follower

Envelope follower

Top

Current state: Version 0.9.0 published

This envelope follower was first build for my Shakuhachi 2 Synth project. But it is useful for any other input signal which you want to derive a control voltage from. It provides a gate and a trigger signal as well. The envelope follower is used to detect the amplitude variations of the incoming signal and produces a control voltage that resembles the variations in the input signal. The gate and trigger signal is derived from the input signal as well. You can vary the threshold to determine at what minimum signal level the gate goes high and the trigger fires. Gate level is +5V. Trigger level is +5V/1msec.

Microfone preamp

Microfone preamp

Top

Current state: Version xxx To be published

tbd

Voltage refernce Source

Voltage reference

Top

Current state: Version xxx To be published

tbd

DC Mixer

DC Mixer

Top

Current state: Version xxx To be published

tbd

Housing I

Housing

Top

Current state: To be published

tbd

Housing II

Top

Current state: To be published

tbd

Sitelist

Home