Keyboard temperament from the title page of Bach's "Das wohltemperirte Clavier" (1722).

The step-by-step explanation here shows how it is derived. Two full-length performances on harpsichord are included: Bach's C major and B major preludes from this book.

Research by Bradley Lehman, 2004, continuing a doctoral project from 1993-4 in "modified meantone" tuning as applied to Bach's music. The interpretation is based on analysis of Bach's extant keyboard music, plus a historical study of tuning methods, plus (in 2004) the suspiciously irregular drawing on Bach's title page.

This research was first published in an _Early Music_ (Oxford University Press journal) article, February-May 2005. Two printed portions and five web files comprise that article.

The resources are available at http://www.larips.com

See http://www-personal.umich.edu/~bpl/larips/art.html for an article similar to this video demonstration: explaining how the C major and B major scales are blended together to derive all 12 notes of the chromatic scale, and tuned in this manner.

The academic articles are freely downloadable from http://www-personal.umich.edu/~bpl/larips/outline.html
and CD recordings are available as well:
http://www-personal.umich.edu/~bpl/larips/recordings.html

The two recordings heard here are from the CD "Playing From Bach's Fancy":
http://www-personal.umich.edu/~bpl/larips/cd1003.html

Enjoy!

Dr Bradley Lehman
http://www.larips.com (less info)