Investigating parameter mapping of the digital musical instrument Force Ghost

Sammanfattning: This paper investigates the viability of two different mappings of two parameters of the digital musical instrument Force Ghost. The instrument produces sound by having an  ambience (a recording of rain or of waves on the beach) filtered by bandpass filters  whose center-frequencies are controlled by a midi-keyboard. Five bandpass filters are assigned to each note, corresponding to the fundamental frequency its and its multiples (2f,3f,4f,5f). The mapped parameters are the Q-factor of the bandpass filters and the timbre, defined as the relative level between the even and odd multiples harmonics. These two parameters are mapped to the modulation wheel and the pitch bend wheel. The mappings of the parameters are investigated with the help of musical tasks completed by musicians rounded up with semi-structured interviews. The interviews revealed that the modulation wheel was to be prefered due to the lack of a spring mechanism (which is an attribute of the pitch bend wheel), forcing the wheel back to its default position (in the middle) when released. The results from the musical tasks suggested an indication that none of the sensors have better controllability than the other, regardless of parameter it controls. In conclusion, a sensor that gravitates towards a resting state does not seem to be suitable to control a parameter (scaling) that lacks a “resting value” (as perceived by musicians).