The goal of our research is to find ways of supporting and encouraging musical behavior by non-musicians in shared public performance environments. Previous studies indicated simultaneous music listening and performance is difficult for non-musicians, and that visual support for the task might be helpful. This paper presents results from a preliminary user study conducted to evaluate the effect of visual feedback on a musical tracking task. Participants generated a musical signal by manipulating a hand-held device with two dimensions of control over two parameters, pitch and density of note events, and were given the task of following a target pattern as closely as possible. The target pattern was a machine-generated musical signal comprising of variation over the same two parameters. Visual feedback provided participants with information about the control parameters of the musical signal generated by the machine. We measured the task performance under different visual feedback strategies. Results show that single parameter visualizations tend to improve the tracking performance with respect to the visualized parameter, but not the non-visualized parameter. Visualizing two independent parameters simultaneously decreases performance in both dimensions.