Details of sizes needed
Based on the evidence to date, it appears that we need at least three keyboard sizes. These are the current ‘large’ size (6.5 inch octave), plus the DS6.0® (approx 15/16) and DS5.5® (approx 7/8) of the current width. David Steinbuhler has named these sizes as DS6.5 , DS6.0® and DS5.5®. (DS stands for Donison-Steinbuhler.)
The DS5.5® is particularly important in that it removes the advantage that men have over women due to average hand span differences. It is also suitable for children. (See: Hand span data)
The DS6.0® is a potential ‘universal’ size that would suit many private homes and public venues very well. A pianist can adapt to it almost immediately. This size is immediately popular with many who try it even for a short time.
There may also be a market for an even smaller sized keyboard designed mainly for children, with a 5.1 inch octave (DS5.1®). Already, some adults with very small hands have chosen a 5.1 inch octave keyboard for themselves from the Steinbuhler company.
Standard sizes and names
Manufacturers of acoustic and digital pianos producing keyboards in different sizes will benefit from increased demand. Clearly, it will be necessary for manufacturers to limit the number of keyboard sizes for mass produced pianos and keyboards.
We strongly recommend that manufacturers adopt standardized key widths for keyboards of different sizes.
The alternative sizes will ideally be labelled in a consistent way for the benefit of consumers and pianists, and to reduce confusion in the market place. Manufacturers should direct any queries about the use of the DS labels to the DS Standard Foundation Inc. : http://dsstandardfoundation.org
Grand pianos with interchangeable keyboards
For grand pianos, manufacturers should provide consumers with the option of purchasing more than one interchangeable action/keyboard. This will provide maximum flexibility for schools and conservatoriums, piano competitions and concert halls.
But consumers should of course have the option of choosing just one keyboard for their grand piano. (Currently, a pianist wanting a grand piano with DS5.5® keyboard will first have to acquire a grand piano with conventional keyboard, then purchase a second retrofitted action/keyboard.)