In the early 1990s, Christopher Donison, a pianist, composer and conductor from British Columbia, Canada, met up with Pennsylvanian textile manufacturer and engineer, David Steinbuhler. Together they created a second official keyboard size (the DS standard®), with the long term aim of it becoming universally available.
The first prototype keyboard was built by Steinbuhler & Company in 1994. The company’s first sale in 1996 was to Canadian pianist, Linda Gould, who flew from British Columbia in Canada to try it out. She made an immediate decision to buy a DS5.5® keyboard for her Yamaha grand piano. You can hear her story here: https://www.youtube.com/watch?v=Jn9-c8n0Q3s&list=PLHBn-VaaOCGcAanKWSo7pCA0GFfQa7N1b
Between 1998 and 2005, Steinbuhler invited adult pianists to experiment with a complete range of piano keyboard sizes at their centre in Titusville, Pennsylvania. Participants were able to spend hours or days experimenting and swapping between the different size keyboards. It became clear there was a strong desire for at least two smaller keyboard sizes in addition to the conventional keyboard. To determine the most practical sized keyboard for the smaller-handed pianists, a detailed study was conducted using five keyboards measuring between 38 and 42 inches (96.5-106.7 cm) in overall width. About 15 pianists experimented with these keyboards. Although there was a general desire to play the smallest keyboards, it was found that below 40 inches, the space between black keys became too cramped for all but those with the smallest hands with thin fingers.
Hence, in 2000, Southern Methodist University in Texas, the first US university to retrofit a piano with an ESPK (ergonomically scaled piano keyboard)* keyboard, chose the DS5.5® as the best available choice for the smaller hand sizes. Dr. Carol Leone, Chair of Keyboard Studies at SMU, began to research the benefits of the keyboards. These small keyboard actions can also be installed in pianos of the same make and model with minimal technical adjustment. Dr. Leone travelled with her keyboard action and demonstrated its use at other American universities. Most of these universities consequently acquired their own DS keyboard actions for student use and further research .
Three standards were subsequently defined (octave measurements given represent the total width of seven white keys) as follows:
DS6.5™ (Conventional keyboard) – 6.5 inch (16.5 cm) octave, 48.29 inches (122.7 cm) total width
DS6.0® (Universal keyboard, 15/16 width of conventional – 6.0 inch (15.2 cm) octave, 44.57 inches (113.2 cm) total width
DS5.5® (7/8 keyboard, 5.54 inch (14.1 cm) octave, 41.14 inches (104.5 cm) total width.
More recently, Steinbuhler & Co have added a smaller size:
DS5.1® (Child’s keyboard, 5.11 inch (13.0 cm) octave, 37.94 inches ( 96.37 mm) total width.
The size of the Hofmann keyboard mentioned above was between the DS6.5™ and DS6.0® sizes, with a 6.3 inch octave.
In recent years, renowned pianist and conductor, Daniel Barenboim, has been travelling and performing on pianos with narrower keys.