Effect of Latency on Playing Accuracy of Two Gesture Controlled Continuous Sound Instruments Without Tactile Feedback
The paper reports results from an experimental study quantifying how latency affects the playing accuracy of two continuous sound instruments. 11 subjects played a conventional Theremin and a virtual reality Theremin. Both instruments provided the user only audio feedback. The subjects performed two tasks under different instrument latencies. They attempted to match the pitch of the instrument to a sample pitch and they played along a short sample melody and a metronome. Both the sample sound and the instrument’s sound were recorded on different channels of a sound file. Later the pitch of the sounds was extracted and user performance analyzed. The results show that the time required to match a given pitch degrades about five times the introduced latency suggesting that the feedback latency cumulates over the whole task. Errors while playing along a sample melody increased 80% by average on the highest latency of 240ms. Latencies until 120ms increased the errors only slightly.