  This paper investigates the integration of force feedback in Digital Musical
Instruments (DMI), specifically evaluating the reproduction of intricate
vibrato techniques using haptic feedback controllers. We introduce our system
for vibrato modulation using force feedback, composed of Bend-aid (a web-based
sequencer platform using pre-designed haptic feedback models) and TorqueTuner
(an open-source 1 Degree-of-Freedom (DoF) rotary haptic device for generating
programmable haptic effects). We designed a formal user study to assess the
impact of each haptic mode on user experience in a vibrato mimicry task. Twenty
musically trained participants rated their user experience for the three haptic
modes (Smooth, Detent, and Spring) using four Likert-scale scores: comfort,
flexibility, ease of control, and helpfulness for the task. Finally, we asked
participants to share their reflections. Our research indicates that while the
Spring mode can help with light vibrato, preferences for haptic modes vary
based on musical training background. This emphasizes the need for adaptable
task interfaces and flexible haptic feedback in DMI design.
