Notes

Slide Show

Outline

1	“Listening Tests Performed Inside a Virtual Room Acoustic Simulator”
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3	Theatre la Fenice, Venice The first theatre was realised in 1792 by Gian Antonio Selva, after the burning of Teatro San Benedetto In December 1836 the theatre burned down again and was rebuilt by G. and T. Meduna the year after The theatre was closed in 1995 for maintainance; it had to open again in February 1, 1996, but it burned two days before (January 29, 1996) A few weeks before the fire, L.Tronchin measured binaural impulse responses
4	Acoustical measurements Measurements were performed by L.Tronchin in November-December 1995 with a modified gun (with omnidirectional diffuser) and binaural microphones The goal was to analyze some acoustical problems about intercommunication between orchestra pit and stage and to gather information for designing the orchestra shell The data were processed with the software Aurora, which had been developed just 2 months before.
5	Acoustical measurements
6	Impulse Responses of La Fenice
7	Auralization Examples – La Fenice Dry music Convolution with experimental I.R. (pt. 12) Convolution with computer-simulated IR
8	The Past
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11	Teatro Regio in Parma (Italy)
12	Teatro Valli, Reggio Emilia, Italy
13	Paganini Auditorium, Parma, Italy
14	S.Cecilia Auditorium 700, Rome, Italy
15	Teatro Olimpico, Vicenza, Italy
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21	Theory of inverse filters
22	Combined transfer functiom
23	Possible designe strategies for an equalizing filter Mourjopoulos – Least-squares recursive method in time domain – the whole frequency range is always completely inverted. Neely & Allen – the filter is designed in the frequency domain – only the magnitude of the transfer function is inverted, so the equalized system will have flat frequency response, but it will still be “smeared” in time. Nelson & Kirkeby – again in the frequency domain, but the whole complex value is inverted, adding a small regularization quantity at the denominator for avoiding instabilities and ensuring a finite lenght of the inverse filter
24	Theory of Kirkeby inversion Step 1 – pass to frequency domain through FFT
25	Regularization parameter e(w) variable with frequency
26	Example A loudspeaker+microphone system was measured:
27	Inverse filter example System’s impulse response
28	Inverse filter example Convolution of inverse filter with the system’s impulse response
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36	The Present
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40	Modern multiple-format microphonic systems
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48	Stereo Dipole inverse filters
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52	GOALS of the new subjective experiment
53	Conclusions (preliminary yet)
54	The Future
55	Future improvement of the listening room
56	ITU 5.1 surround Williams MMA
57	ITU 5.1 surround OCT
58	Ambisonics 3D 1^st order Reproduction occurs over an array of 8-24 loudspeakers, through an Ambisonics decoder
59	The Soundfield microphone
60	The B-format components
61	Ambisonics decoding
62	A software Ambisonics decoder
63	Rooms for Ambisonics 3D 1^st order
64	Virtual high-order microphones (M. Poletti) One of the two ORTF cardioid is employed, which samples 36 positions along a 110 mm-radius circumference
65	Ambiophonics 3D (10 loudspeakers):
66	Ambiophonics Room at ASK
67	Ralph Glasgal’s Ambiophonics Room at the Ambiophonics Institute
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