Numerical Sound
Audio and Sound ProductsAudio and Sound ServicesClients of Numerical SoundAbout Numerical SoundMediaFrequently Asked QuestionsNumerical SoundWelcomeContact
About Numerical Sound  
Numerical Sound
Numerical Sound

About Numerical Sound


Glen Gould Aria
Glen Gould: Bach's Goldberg Variations


Sample Velocity
Sound Analysis of Swing
Tempi Changes on the Blüthner


Projects: Glen Gould - Bach's Goldberg Variations

Midi Re-Creation of A Glen Gould Performance

The piano Glen Gould used for the 1981 recording of the J. S. Bach's Goldberg Variations. This piano is currently at Roy Thompson Hall , Toronto, Canada.

Glen Gould's Legendary Sony Recording of Bach's Goldberg Variations recreated live on a Yamaha Diskclavier by Sound Architect Ernest Cholakis.

Glen Gould recorded Bach's Goldberg Variations for Sony in 1981 on the Yamaha C9 piano owned by the pianist. It was to become his most successful recording selling 1.8 million copies to date.

Last year an important creative project was undertaken when Sound Architect Ernest Cholakis was given permission by the Roy Thomson Hall to sample and analyze Gould's original piano. Cholakis was commissioned by The National Ballet of Canada to transcribe and then recreate on a Yamaha Disklavier the 1981 Glen Gould performance of the Aria from Bach's Goldberg Variations for their performance of "Inspired by Gould".

Cholakis' project was unique in that it was the first time technology would be applied to recreate a legendary recording live. To undertake this Cholakis applied his over 20 years of experience working with music and computer technology (with an Apple PowerPC) to do the necessary analysis.Cholakis developed the proprietary software to analyze and then create a midi file for the Yamaha C7 disklavier, made available by Yamaha Canada, which was able to approximate the timing, the attack velocity and duration of Gould 's original performance in the 1981 Sony Recording.

The piano Glen Gould used for the 1981 recording of the J. S. Bach's Goldberg Variations. This piano is currently at Roy Thompson Hall , Toronto, Canada.

The intent was to have it sound and feel as if Glen Gould was performing live for the ballet and as one ballet critic G. Sumi noted "a player piano spookily hinting that the pianist's spirit has come back to haunt us." Now Magazine, Toronto, November 25, 1999. As well as theatrically evoking Gould's haunting presence on stage when the keys of the piano moved without Gould at the stool, the musical results offered an emotionally moving emulation of the pianist's Goldberg performance of 1981.

A midi file/Yamaha C7 disklavier recreation of Glen Gould's feel of the aria from Bach's Goldberg Variations (based upon the 1981 performance) - Listen to midi file recreation (MP3, 738K, the first 16 bars)

A Comparison of the Piano Resonance of Glen Gould's Piano used in the 1981 Recording of J. S. Bach's Goldberg Variations and a Yamaha Disklavier C7 (special thanks the Stan Zalinski at Yamaha Canada for lending me this piano). Permisssion to record Glen Gould's Piano was given by Massey Hall and Roy Thomson Hall (special thanks to Denese Mitchell). B&K 4003 with a Millenniam HV-3B Pre-Amp was used to record the piano (special thanks to Laurence Stevenson at the Canadian Broadcasting Corporation).

The Resonance comparison (spectrum) is in Amplitude (decibel) vs. Equal Temperament Pitch instead of the much more common frequency. This gives an indication of just how complex real world instruments are (which all of our ears easily recognizes). Note the difference in the low frequencies between a 9 and a 7.6-foot Yamaha.

Sound resonance of two Yamaha pianos

This is a comparison of the overall sound resonance (audio spectrum) of two Yamaha pianos in the range of A0-C8. The vertical axis is the energy in decibel and the horizontal axis is the frequency in midi notes (Middle C is C4=60). The C9 (top graph) was owned by Glen Gould and used to record Bach's Goldberg Variations (1981).

© 1999-2005 Numerical Sound Notice of Rights All Rights Reserved. No Part of this image may be reproduced in any form without prior written permission. For Information on getting permission for reprints, excerpts or further details, contact Ernest Cholakis at Numerical Sound,, 414-444-6644, (FAX 416-444-7045).