SEGMENTAL TEMPO ANALYSIS OF PERFORMANCES IN USER-CENTERED EXPERIMENTS IN THE DISTRIBUTED IMMERSIVE PERFORMANCE PROJECT

Publication Type:

Conference Paper

Source:

SMC Conference 2005 (2005)

URL:

files/proceedings/2005/cstz-smc05_final.pdf

Abstract:

In this paper we present a quantitative analysis of performer-based experiment data in the Distributed Immersive Performance Project. The experiments explore the effects of auditory latency on musical ensemble and interpretation in order to determine the thresholds for usability. We propose two measures – the segmental tempo difference and the segmental tempo ratio from a baseline performance – as objective quantifiers of performance strategies. Our earlier analyses of qualitative reports showed that the usability threshold lies between 50 and 75 ms. We demonstrate that the proposed analyses of the performance data, captured in MIDI format, lead to results similar to the reports. The tempo difference and tempo scaling across logical segments of the piece show marked increase in variability when the auditory delay is in the range of 50 to 100 ms (for two examples) and 50 to 75 ms (for the most rapid example). The span of the tempo difference and ratio values at latency 150 ms is less than that around the usability thresholds. We surmise that around the threshold, the users attempt numerous performance strategies to compensate for the delay; at latencies far above the threshold, such strategizing fails and the performers revert to more stable practiced norms. These findings indicate that segmental tempo difference and ratio analyses are useful indicators of performance decisions, and that quantitative analysis of performance data may be a viable way of evaluating the psychophysical effects of collaborative performance under various immersive conditions.