Physical Modeling on the Nord Modular G2

Physical Modeling on the Nord Modular G2

Chet Singer

Updated June 23, 2006

Introduction

The Nord Modular G2 is an electronic music synthesizer produced in Sweden by Clavia. Clavia manufactures a variety of electronic keyboard instruments. The G2 lets the owner build a wide variety of sounds by connecting various kinds of sound “modules” together. “Modules” represent sound-processing electrical circuits, such as oscillators and filters, and are connected together using virtual “wires”. In this sense, the G2 is a modern version of the modular synthesizers first made popular in the 60s and 70s.

The G2 includes a wide variety of modules, and supports a variety of synthesis methods. One of these methods is physical modeling, the attempt to mimic real-world instruments by approximating their physics. Although the G2 wasn’t specifically designed to be a physical-modeling synthesizer, it has all the modules necessary to model many types of instruments, including:

Plucked Strings

Blown Pipes

Woodwinds

Brass Horns

Bowed Strings

Pipe Organs

The term “physical modeling” can describe several different kinds of synthesis. Some examples are:

Modal Synthesis: This technique is used by the Tassman softsynth. Modal synthesis is basically a collection of parallel high-resonance bandpass filters, excited by an input impulse. The filters model the resonances in objects such as strings, pipes, bars, plates, and membranes. Each filter has three parameters: frequency, resonance (decay time), and output level. It is especially good for simulating struck sounds, like rods, bars, and plates.

Waveguide Synthesis: This technique is used by instruments such as the Yamaha VL1 and the Korg Z1. It uses delay lines to simulate a sound wave traveling along a string or pipe. It is especially good for simulating string and wind instruments.

These pages describe models made with waveguide synthesis. Patch images are linked to the associated G2 patch file.

The Purpose of These Pages

These pages are meant to teach basic waveguide modeling techniques. Physical modeling has a reputation of being hard to understand, and I hope these pages can help take some of the mystery out of it.

The Pages

Blown Pipes

Using a breath controller

Putting it all together

Flutes

Introduction to pulsed noise

Bells and whistles

Using a breath controller

Putting it all together

Reed Woodwinds

The basic reed woodwind

Tuning the bore

Legato phrasing

Stabilizing the model

Post-processing and EQ

Putting it all together

Brass

The bugle

A generic brass horn

The trombone slide

The 3-valve switching system

Trumpets

Pipe Organs

The basic organ pipe

Adding more pipes

Bowed Strings (in progress)

The basic plucked string

Bowing the string

Tuning the string

Randomized vibrato

Modeling the cello’s wooden body

Adding bow force

Adding bow noise

Note-to-note transitions

The final single-string cello

Adding a second string

Creating a violin, a viola, and a contrabass

Some Sound Examples

Here are some short examples of physical modeling. All sounds are physical models, performed on the G2. All models except the guitars and pipe organs were played using a breath controller.

Hornpipe from Water Music Suite #1, by George Frideric Handel. Performed by an oboe, a bassoon, a clarinet, and an English horn. The patches are available in the Woodwind Patch Collection.

A fragment of a fanfare from George Frideric Handel’s Water Music, performed by a trumpet and two trombones. The patches are available in the Brass Patch Collection.

The beginning of the prelude of Bach’s first cello suite, performed by a solo cello (what else?).

A fragment of the Princess Leia Theme from Star Wars, written by John Williams, and performed by three cellos.

All Glory, Laud, and Honor, an English hymn sung to a 17^th century tune written by Melchior Teschner, and performed by four flutes. The patches are available in the Woodwind Patch Collection.

I Sing the Mighty Power of God, an English hymn sung to a German tune published in 1784 in the Gesangbuch der Herzogl. This is an SATB arrangement performed by two trumpets and two trombones. The patches are available in the Brass Patch Collection.

Three violins and a cello playing the first phrase from George Frideric Handel’s The Trumpet Shall Sound. The same phrase played with three cellos.

An excerpt from some incidental music on a British Sherlock Holmes television show. Performed by two guitars and a recorder.

A Bach Minuet, performed on a pipe organ.

All Creatures of our God and King, a 17^th century German hymn, performed by two trombones and two trumpets.

The introduction to George Frideric Handel’s The Trumpet Shall Sound, from the “Messiah” oratorio. Performed by a small string orchestra, a trumpet, and a trombone.

A fragment of We Will Glorify, a Twila Paris tune, performed on a pipe organ.

Completed G2 Patches

I’ve been wanting to offer some complete, ready-to-use models that mimic particular instruments. Two sets are now available:

Woodwind Patch Collection.

Brass Patch Collection.

Miscellaneous Notes

This is a work in progress. I’ll add pages as I have the opportunity.

All patches have been saved using OS version v1.4.

Who Am I

I am an amateur musician and synthesist. I’m a physicist by education, and a computer programmer by trade, specializing in factory automation, warehousing, and logistics.

I’ve been interested in synthesis since the mid-1970s, when a local music store let me experiment with the ARP synthesizers they sold. In the 1980s and 1990s, I built a few small homemade synthesizers. My interest in physical modeling began in 1996, when I purchased an Analog Devices circuit board that contained an ADSP-2181 digital signal processor. I had hoped to build a synthesizer around it. One of the demonstration programs that came with it was a rendition of “Stairway to Heaven”, played using a Karplus-Strong plucked string algorithm. And I’ve been hooked ever since.

If anyone wishes to contact me, I hang out in the Clavia G2 forum hosted at www.electro-music.com, as “Chet”, or in the Keyboards forum at www.harmony-central.com, as “ChetSinger”.

Acknowledgements

Most of my knowledge has come by reading. I’ve read many papers by many authors, and want to extend my thanks to the following:

Dr. Chris Chafe

Dr. Jim Clark

Dr. Perry Cook

Mr. Ken Elhardt

Dr. Knut Guettler

Mr. Rob Hordijk

Dr. Toshifumi Kunimoto

Dr. Gary Scavone

Dr. Stefania Serafin

Dr. Julius Smith

Dr. Vesa Välimäki

I want to extend special thanks to Drs. Perry Cook and Gary Scavone, the authors of the Synthesis Tool Kit (STK). STK is synthesis development software that contains many physical modeling instruments and modules. Although there is much written information about physical modeling, little of it is precise and detailed enough to create models on the G2. STK is an exception, and contains working C++ source code that can be studied. Some of the techniques in these pages were lifted right out of STK.

I also want to extend special thanks to Rob Hordijk and Jim Clark. They’ve both written excellent tutorials on the use of the Nord Modular. It was their papers that convinced me the Nord Modular would be a suitable platform for experimentation in physical modeling.

Change History

Date	Description of change
September 4, 2004	Tutorial created, including Introduction and Blown Pipe pages.
September 27, 2004	Background texture changed on all pages. Minor corrections made on Blown Pipe patches and pages. Flute pages added. Two Reed Woodwind pages added.
October 7, 2004	Finished Reed Woodwind pages and added Brass pages.
December 27, 2004	Added sound examples to the main page.
January 3, 2005	Added Pipe Organ pages. Added the Bach Minuet mp3.
January 4, 2005	Added text to the introduction. Added the Twila Paris pipe organ mp3.
June 3, 2005	Added a zip file containing slides and patches from Electro-Music 2005.
June 29, 2005	Fixed the main page. Added the “Three violins and a cello” mp3.
April 4, 2006	Re-tuned the patches with G2 OS version 1.4. Switched to Arial font. Re-organized the mp3s. Added the “three cellos” mp3. Added the Woodwind Patch Collection and the Hornpipe mp3.
April 21, 2006	Added the saxophone patch to the Woodwind Patch Collection.
May 6, 2006	Added the flute patch to the Woodwind Patch Collection. Added the “All Glory, Laud, and Honor” mp3.
June 19, 2006	Added the Brass Patch Collection and the “Water Music Fanfare” and “I Sing the Mighty Power of God” mp3s.
June 23, 2006	Added the Princess Leia theme mp3.