ERATO Proceedings Istanbul 2006.pdf - Odeon

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eal theatres. The cavea of the model consists of nine different slices each divided in three different parts: the lower, the middle and the upper tiers of steps. Actually two different versions of the lower parts were prepared in order to take into account the different slopes of the steps introduced in RO. Movable parts were also designed to be able to modify the cavea structure and introducing the two diazoma added in HE and RO respectively. Therefore, the cavea of GE is built by joining the lower and the middle part of the nine slices. Then, in the HE configuration, the upper part of the cavea and the columns are added and three rows of steps are removed to create the diazoma major. Finally, the RO theatre is obtained by swapping the first tiers of steps and creating the diazoma minor. For each configuration the appropriate stage building was added in front of the respective cavea. The three different configurations of the scale model are showed in Figure 1. The structure of wooden beams supporting the cavea and the split in nine slices can also be observed. a b c Figure 1. The scale model: a) Greek theatre - GE, b) Hellenistic theatre - HE, c) Roman Theatre - RO. 36
4 MEASUREMENT SETUP A high frequency measurement chain is necessary to take acoustical measurements in a scale model. Considering the 1:20 scale factor, a 192 kHz A/D converter was chosen to get a frequency response up to 4.8 kHz in the real scale. Moreover two types of sound sources and two different microphones were tested in the measurements. This was done in order to optimize the measurement chain both for the acoustical parameters and for the study of the reflection patterns. 4.1 Sources Two different sound sources were used for the measurements: a piezoelectric miniaturized dodecahedron and a spark source. The first one is a dodecahedron with a diameter of 8 cm where the loudspeakers are replaced with piezoelectric transducers. Its frequency response is rather flat up to 90 kHz. The second source is a newly made spark consisting of a high voltage generator that drives a spinterometer. The shape of the spinterometer was optimised to obtain an omnidirectional emission in the horizontal plane. The spark emission rises with a slope of 9 dB per octave. This type of source produces a very sharp and powerful impulse which was very useful to analyze the reflection patterns in the impulse responses. The spark was also used for auralizations and the results sounded quite realistic probably due to peculiar frequency response of the spark, which compensates for the air absorption at very high frequencies. 4.2 Microphones For the signal acquisition two different microphones were tested: a 1/4” and a 1/8” measurement microphones. The 1/8” microphone has a flat response up to 140 kHz but a very low sensitivity (1 mV/Pa) and the 1/4” microphone has a much higher sensitivity but the frequency response is flat only up to 80 kHz in a free field. All possible source-microphone combinations were tested to find the best results in term of S/N ratio and good extension in frequency. The optimum choice for the measurement of the acoustical parameter was the 1/4” microphone together with the piezoelectric source. 4.3 Signal Generation and Acquisition The measurements chain included a desktop PC with an audio card with a sampling rate of 192 kHz. The 1:20 scale of the model gave acoustical parameters up to almost the complete 4 kHz third octave band in the real scale. To measure the impulse responses a sine sweep from 500 Hz to 95 kHz was used and the software for generation, recording and processing was the Aurora plug-in for Adobe Audition. 4.4 Measurement Positions For each theatre configuration two source positions were chosen. The former is in the orchestra, close but not coinciding with the geometrical centre to avoid the focusing effects caused by the semicircular shape. This position is exactly the same for all the theatres to allow direct comparisons. The latter position was on the stage for HE and RO. Since GE has no front stage (the area is 37
Page 1: RTD project in the EC 5th Framework
Page 7 and 8: THE ERATO PROJECT AND ITS CONTRIBUT
Page 9 and 10: 3 ROOM ACOUSTICAL PARAMETERS The fo
Page 11 and 12: 4.2 Reverberation Time T 30 vs. Fre
Page 13 and 14: 5.1 Aosta & Aphrodisias Odeon The A
Page 15 and 16: 5.3 Strength G vs. Distance 16,00 1
Page 17 and 18: VITRUVIUS AND ANCIENT THEATRES: ANA
Page 19 and 20: a line is drawn to touch the outsid
Page 21 and 22: Actually the colonnade (portico) im
Page 23 and 24: VIRTUAL REALITY AND ARCHITECTURAL C
Page 25 and 26: As a result, maybe the most critica
Page 27 and 28: The absorption and scattering prope
Page 29 and 30: Figure 3. Sound sources and receive
Page 31 and 32: In Figure 5 the reverberation time
Page 33 and 34: ACOUSTICAL MEASUREMENTS IN ANCIENT
Page 35 and 36: channels four different signals, on
Page 37 and 38: The clarity for music C80, whose pl
Page 39 and 40: References [1] EU Project ERATO - I
Page 41: 2.1 The Greek Theatre The GE theatr
Page 45 and 46: stage building causes the RT to dec
Page 47 and 48: 5.3 The Sound Level In Figure 6 the
Page 49 and 50: colonnade where the stage wall as a
Page 51 and 52: Table 1. Theaters and odea to work
Page 53 and 54: A Color Order System is a method of
Page 55 and 56: Figure 9. Seating rows of Jerash Th
Page 57 and 58: Figure 11. Lightmap and diffusemap
Page 59 and 60: Interactive visualization of the As
Page 61 and 62: oofing, the works of Izenour [11] w
Page 63 and 64: 3.5 Real-time Illumination with ‘
Page 65 and 66: correlation between the parameters
Page 67 and 68: Third, once the texturing and garme
Page 69 and 70: [19] Tecmath AG. Avilable from http
Page 71 and 72: 2 Crowd Engine Resume The crowd eng
Page 73 and 74: 3 Scenario Authoring Since the begi
Page 75 and 76: Part Description User control 1.0 I
Page 77 and 78: 3.4 Results To conclude, Fig 6 illu
Page 79 and 80: ANCIENT THEATRES AND ODEA AND CRITE
Page 81 and 82: 3. Conferences and Receptions: Oran
Page 83 and 84: 6 CHARTERS and the USE of ANCIENT P
Page 85 and 86: 7. Interpretation and presentation
Page 87 and 88: References [1] ICOMOS - Internation
Page 89 and 90: The measurements performed by UNIFE
Page 91 and 92: 1.3 Assessment of acoustic preferen
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Distance 90,0 80,0 70,0 60,0 50,0 4
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References 1] Barron, M: 2004 The c
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YTU Theatre Club “Male Group Acto
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