Just Keys

 

Photo by Will Gullette

 

 

 

 

1.
Good-Bye, by Cris Forster
Isabelle Jotterand, Just Keys

 

 

 

2.
Farewell, by Cris Forster
Isabelle Jotterand, Just Keys

 

 

 

3.
Far Away, by Cris Forster
Cris Forster, Just Keys

 

 

 

4.
In the Park, by Cris Forster

Joseph Rogers, Just Keys

5.
The Letter, by Cris Forster

Cris Forster, Just Keys

 

 

 

6.
Blue Nights, by Cris Forster

David Boyden, Bass Canon
Heidi Forster, Glassdance
Isabelle Jotterand, Just Keys
Benjamin Koscielak, Bass Marimba

 

 

 

 

          Just Keys is a medium upright or console piano that I tuned in just intonation. In 1990, I restrung this instrument three times and retuned it four times. The graphic above shows the complete keyboard, with Lexan-covered colored labels, from the first key in the bass to the last key in the treble.

 

          Note that the B-3 key identifies ratio 1/1, which is the fundamental frequency of the tuning. This key sounds G1 at 49.0 cps! Since the G-11 key normally produces this frequency, observe that I eliminated most of the tones that comprise the first octave of the standard piano. Consequently, the A-1 key now sounds frequency ratio 8/5, or a just major third, interval ratio 5/4, below 1/1, which is Eb1 at 39.2 cps; and the A#-2 key now sounds frequency ratio 16/9, or a just major second, interval ratio 9/8, below 1/1, which is F1 at 43.6 cps.

 

          A 10-tone octave, ratios 1/12/1, exists from the B-3 key to the A-13 key (two keys with two dark blue labels); a 17-tone octave, ratios 2/14/1, from the A-13 key to the D-30 key (two keys with two dark blue labels); and another 17-tone octave, ratios 4/18/1, from the D-30 key to the G-47 key (two keys with two dark blue labels). From here, three consecutive 12-tone octaves, ratios 8/116/1, ratios 16/132/1, and ratios 32/164/1 span the distance from the G-47 key to the G-83 key. These 12-tone scales resemble the tuning of a conventional piano. Short string lengths determined by the shape of the cast iron plate and the location of the treble bridge severely restrict alternate tuning possibilities in the upper treble range.