for future reference pg 43 of the psr-k1"s manual
http://www2.yamaha.co.jp/manual/pdf/emi/english/port/PSRK1E.pdfThe Touch Response feature gives you the natural expressiveness of an acoustic instrument, such as that of a real piano—letting you dynamically alter the volume of the notes with your playing technique and strength. If you want to disable this feature and have all notes sound at the same volume, set Touch Response to OFF.
■ Turning Touch Response on/off
Turn the Touch Response on or off by pressing the [TOUCH] button.
When the Touch Response is on, the Touch Response icon in the display lights up. When Touch Response is off, the icon goes out.
■ Setting the sensitivity of Touch Response