Identification of concert halls was studied to uncover whether the early or late part of the acoustic response is more salient in a hall's fingerprint. A listening test was conducted with auralizations of measured halls using full, hybrid, and truncated impulse responses convolved with anechoic symphonic music. Subjects identified halls more reliably based on differences in early responses rather than late responses, although varying the late response had more effect on acoustic parameters. The results suggest that in a typical situation with running symphonic music, the early response determines the perceptual fingerprint of a hall more than the late response.

In concert halls, the spectrum of direct sound (here 0 to 15 ms) is influenced by the seat-dip effect that causes selective low frequency attenuation. The seat-dip effect has been considered to be detrimental to the acoustic quality of halls, yet there is little evidence about the perceptual significance of the effect. This paper studies the discrimination and preference of seat-dip effect related changes in the direct sound, with realistic auralization of multichannel anechoic orchestra recordings in halls measured with the loudspeaker orchestra. Comparisons are made with a free-field direct sound and direct sound magnitude changes typically associated with the seat-dip effect. Overall, the differences were not significantly audible, except with a subgroup of participants in one out of four halls, and two out of three comparisons. Furthermore, participants' preference for the uncolored direct sound was significant in the halls with less reflected energy, but non-significant in the halls with more reflected energy. The results imply that for most seats in adequately reverberant halls, typical seat-dip effect related coloration in the direct sound can be perceptually negligible.

The preferred level balance between the direct, early, and late components of the sound field in a concert hall was studied by letting listeners manipulate sound field auralizations in an adjustment procedure featuring acoustics of two halls of contrasting designs; Berlin Konzerthaus (shoebox) and Berlin Philharmonie (vineyard). The room impulse responses measured at two positions in each hall were encoded for multichannel reproduction, split into direct, early, and late components, convolved with anechoic recordings of a symphony orchestra, and reproduced in a multichannel listening room. The listeners' task consisted of optimizing the level balance between the direct, early, and late components by adjusting the level of two of the components relative to one that was kept fixed. The results reveal a strong tendency to emphasize the early component for both positions in Berlin Philharmonie, where the early reflections contain less energy due to the fan shaped frontal auditorium and comparatively small effective side wall areas. In contrast, the median results for one position in Berlin Konzerthaus were within 1.5 dB of the actual acoustics of the hall, with statistically insignificant deviations. The relationship between the direct sound and early reflections is seen as a potential subject of further study.

Recently, the Department of Media Technology at Aalto University offered a seminar entitled Applied Data Analysis and Visualization. The course used spatial impulse response measurements from concert halls as the context to explore high-dimensional data visualization methods. Students were encouraged to represent source and receiver positions, spatial aspects, and temporal development of sound fields, frequency characteristics, and comparisons between halls, using animations and interactive graphics. The primary learning objectives were for the students to translate their skills across disciplines and gain a working understanding of high-dimensional data visualization techniques. Accompanying files present examples of student-generated, animated and interactive visualizations.

Direct-to-reverberant ratio threshold for localization was studied with anechoic orchestra instrument recordings in auralized concert halls. Excerpts of anechoic music were convolved with spatial impulse responses and reproduced with a multichannel loudspeaker system in anechoic chamber. Participants adjusted direct sound level in order to explore the transition range of localizability, with separate tasks for precise and imprecise localization. Halls with contrasting acoustics, and excerpts with pairs of instruments from the main orchestra instrument families, were used to estimate the range of influence of hall and excerpt. Statistical analysis was done using linear mixed models. Estimate for the localization threshold of halls was between-2.7 dB to 1.7 dB direct-to-reverberant ratio in the 700-4000 Hz frequency band. Hall had a significant effect on the threshold (around 3 dB), and excerpt had a significant effect on the imprecise threshold (around 4 dB). The interaction of hall and excerpt was also found significant for the imprecise threshold. Transition between imprecise and precise localization was associated with a 5-8 dB direct sound level difference.