Graphically Interpolated Synthesis Parameters for Sound Design: Usability and Design Considerations

Editors: Polfreman, R.

Conference: University of Southampton, School of Music

Abstract:

This research investigates the use of graphical interpolation to control the mapping of synthesis parameters for sound design, and the impact that the visual model can have on the interpolator’s performance and usability. Typically, these systems present the user with a graphical pane where synthesizer presets, each representing a set of synthesis parameter values and therefore an existing sound, can be positioned at user-selected locations. Subsequently, moving an interpolation cursor within the pane will then create novel sounds by calculating new parameter values, based on the cursor position and an interpolation model. These systems therefore supply users with two sensory modalities, sonic output and the visual feedback from the interface.

A number of graphical interpolator systems have been developed over the years, with a variety of user-interface designs, but few have been subject to formal user evaluation making it difficult to compare systems and establish effective design criteria to improve future designs. This thesis presents a novel framework designed to support the development and evaluation of graphical interpolated parameter mapping. Using this framework, comparative back-to-back testing was undertaken that studied both user interactions with, and the perceived usability of, graphical interpolation systems, comparing alternative visualizations in order to establish how the visual feedback provided by the interface aids the locating of desired sounds within the space. A pilot investigation compared different levels of visual information, the results of which indicated that the nature of visualisation did impact on user interactions. A second study then reimplemented and compared a number of extant designs, where it became apparent that the existing interpolator visuals generally relate to the interpolation model and not the sonic output. The experiments also provide new information about user interactions with interpolation systems and evidence that graphical interpolators are highly usable in general.

In light of the experimental results, a new visualization paradigm for graphical interpolation systems is proposed, known as Star Interpolation, specifically created for sound design applications. This aims to bring the visualisation closer to the sonic behaviour of the interpolator by providing visual cues that relate to the parameter space. It is also shown that hybrid visualizations can be generated that combine the benefits of the new visualization with the existing interpolation models. The results from the exploration of these visualizations are encouraging and they appear to be advantageous when using the interpolators for sound design tasks.

Source: Manual