Interacting With Digital Audio Effects Through a Haptic Knob With Programmable Resistance
Live music performances and music production often involve the
manipulation of several parameters during sound generation, processing, and mixing. In hardware layouts, those parameters are
usually controlled using knobs, sliders and buttons. When these
layouts are virtualized, the use of physical (e.g. MIDI) controllers
can make interaction easier and reduce the cognitive load associated to sound manipulation. The addition of haptic feedback can
further improve such interaction by facilitating the detection of the
nature (continuous / discrete) and value of a parameter. To this
end, we have realized an endless-knob controller prototype with
programmable resistance to rotation, able to render various haptic effects. Ten subjects assessed the effectiveness of the provided
haptic feedback in a target-matching task where either visual-only
or visual-haptic feedback was provided; the experiment reported
significantly lower errors in presence of haptic feedback. Finally,
the knob was configured as a multi-parametric controller for a
real-time audio effect software written in Python, simulating the
voltage-controlled filter aboard the EMS VCS3. The integration
of the sound algorithm and the haptic knob is discussed, together
with various haptic feedback effects in response to control actions.