acousticsofthe in venic

12
PAPERS ACOUSTICSOFTHE FORMERTEATRO "LA FENICE" IN VENICE* LAMBERTO TRONCHIN Nuclear, Energetic and Environmental Control Engineering Department, University of Bologna, 1-40136 Bologna, Italy AND ANGELO FARINA, AES Member Department of Industrial and Engineering, University of Parma, 1-43100 Parma, Italy The acoustic characteristics of the former "La Fenice" theater have been analyzed. Binaural measurements of the impulse responses were performed at a large number of measuring points within the hall. Following the recent ISO standard 3382 [1], many mono and binaural acoustical parameters were calculated from the impulse responses, such as reverberation time, clarity, center time, strength, initial time delay gap, interaural cross correlation, and others. Finally, Ando's preference maps were developed, taking into account two different kinds of musical signals. The measurements underlined the peculiar acoustical behavior of the theater, characterized by a greater initial decay of the reverberant tall and a subsequent reverberation that allowed a remarkable fusion of the sound and sustain to the musicians. I HISTORICAL PREVIEW ice acquired a European reputation. Rossini mounted two major productions in the theater and Bellini had In 1774 the San Benedetto theater, which had been two operas premiered here. Donizetti, fresh from his Venice's leading opera house formore than 40 years, triumphs in Milan and Naples, returned to Venice--and burned to the ground. No sooner had it been rebuilt that La Fenice--in 1836, after an absence of 17 years. Thus a legal dispute broke out between the company managing the three greatest Italian composers of the period each it and the owners, the Venier family. The issue was affirmed the theater's preeminence, but in 1836 Decem- decided in favor of the Veniers, with the result that the ber it tragically burned down yet again. The following theater company decided to build a new opera house of year Giambattista and Tommaso Meduna were commis- its own on the Campo San Fantin. From the 29 architec- sioned to design a new theater, with decor by Tranquillo tural plans that were submitted, the one by Gian Antonio Orsi. La Fenice rose once again from its ashes, in Fiorit0 Selva was chosen. The construction began in 1790 June; style, on the evening of 1837 December 26. by 1792 May the auditorium was completed. It was Many world-famous musicians wrote again music named "La Fenice" (the phoenix) in an allusion to the pieces for the "new" Fenice theater. Verdi's association company's survival, first of the fire, then of expulsion with La Fenice began in 1844, with a performance of from its former base. La Fenice was inaugurated on 1792 "Ernani" during the Carnival season. Over the next 13 May 16 with an opera by Giovanni Paisiello entitled "I years, "Attila," "Rigoletto," "La Traviata," and "Simon Giuochi di Agrigento." Boccanegra" all were performed there. The theater at- The hall had a half-elliptic plan, modeled after--it tracted the world's greatest singers conductors, and com- seemed--the Teatro Argentina in Rome. posers, such as Stravinsky, Britten, Berio, Nono, and From the beginning of the nineteenth century, La Fen- Bussotti, who would write for La Fenice. Many people wrote about the elliptic plan of a theater. * Manuscript received 1996 December 10; revised 1997 Au- Pierre Patte, in a 1774 "Essai sur l'architecture th6a- gust 18. tr_le," thought that the elliptic auditorium was the nat- o. AudioEng.Soc., Vol. 45, No. 12,1997December 1051

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Page 1: ACOUSTICSOFTHE IN VENIC

PAPERS

ACOUSTICSOF THE FORMERTEATRO"LA FENICE"IN VENICE*

LAMBERTO TRONCHIN

Nuclear, Energetic and Environmental Control Engineering Department, University of Bologna,1-40136 Bologna, Italy

AND

ANGELO FARINA, AES Member

Department of Industrial and Engineering, University of Parma, 1-43100 Parma, Italy

The acoustic characteristics of the former "La Fenice" theater have been analyzed.Binaural measurements of the impulse responses were performed at a large number ofmeasuring points within the hall. Following the recent ISO standard 3382 [1], manymono and binaural acoustical parameters were calculated from the impulse responses,such as reverberation time, clarity, center time, strength, initial time delay gap, interauralcross correlation, and others. Finally, Ando's preference maps were developed, takinginto account two different kinds of musical signals. The measurements underlined thepeculiar acoustical behavior of the theater, characterized by a greater initial decay of thereverberant tall and a subsequent reverberation that allowed a remarkable fusion of thesound and sustain to the musicians.

I HISTORICAL PREVIEW ice acquired a European reputation. Rossini mountedtwo major productions in the theater and Bellini had

In 1774 the San Benedetto theater, which had been two operas premiered here. Donizetti, fresh from hisVenice's leading opera house for more than 40 years, triumphs in Milan and Naples, returned to Venice--andburned to the ground. No sooner had it been rebuilt that La Fenice--in 1836, after an absence of 17 years. Thusa legal dispute broke out between the company managing the three greatest Italian composers of the period eachit and the owners, the Venier family. The issue was affirmed the theater's preeminence, but in 1836 Decem-

decided in favor of the Veniers, with the result that the ber it tragically burned down yet again. The followingtheater company decided to build a new opera house of year Giambattista and Tommaso Meduna were commis-its own on the Campo San Fantin. From the 29 architec- sioned to design a new theater, with decor by Tranquillotural plans that were submitted, the one by Gian Antonio Orsi. La Fenice rose once again from its ashes, in Fiorit0Selva was chosen. The construction began in 1790 June; style, on the evening of 1837 December 26.

by 1792 May the auditorium was completed. It was Many world-famous musicians wrote again musicnamed "La Fenice" (the phoenix) in an allusion to the pieces for the "new" Fenice theater. Verdi's associationcompany's survival, first of the fire, then of expulsion with La Fenice began in 1844, with a performance offrom its former base. La Fenice was inaugurated on 1792 "Ernani" during the Carnival season. Over the next 13May 16 with an opera by Giovanni Paisiello entitled "I years, "Attila," "Rigoletto," "La Traviata," and "SimonGiuochi di Agrigento." Boccanegra" all were performed there. The theater at-

The hall had a half-elliptic plan, modeled after--it tracted the world's greatest singers conductors, and com-seemed--the Teatro Argentina in Rome. posers, such as Stravinsky, Britten, Berio, Nono, and

From the beginning of the nineteenth century, La Fen- Bussotti, who would write for La Fenice.

Many people wrote about the elliptic plan of a theater.

* Manuscript received 1996December 10; revised 1997 Au- Pierre Patte, in a 1774 "Essai sur l'architecture th6a-gust 18. tr_le," thought that the elliptic auditorium was the nat-

o. AudioEng.Soc.,Vol.45,No.12,1997December 1051

Page 2: ACOUSTICSOFTHE IN VENIC

TRONCHIN AND FARINA PAPERS

ural shape of a theater because the human voice propa- for symphonic music, when the orchestra was located ongates as elliptic acoustic waves, as opposed to other the stage. As in many other opera halls, an orchestra shellacoustic sources that are quite omnidirectional (such as was required to give proper coupling of the stage with thethe bell), main hall during the performances of large ensembles, and

Although now we know that an elliptical shape is to give stronger reflections to the stage.very dangerous, as it can cause focalizations and uneven In the summer of 1995 the artistic direction of thesound distribution, it must be taken into account that theater decided to perform measurements of the acousticfortunately the Italian theaters are not highly reflecting, behavior of the hall, which had to be the basis for thehaving their walls covered with artistic paintings and acoustic design of the orchestra shell. The theater was

stuccos, especially in the neoclassical style, which pre- under restoration to meet the European security start-vent specular reflections and tend to give a diffuse sound dards, and the construction of an orchestra shell had

field. So La Fenice also gained a high reputation with been added to the list of proposed improvements.regard to its acoustic behavior, which was due to theparticular association of an unusual shape and properly 2.1 General Characteristics of the Halladjusted absorption properties. The main hall, typically in the Italian style, had four

The theater maintained its characteristic charm until tiers of balconies plus the last one, called "loggione."it burned again completely on 1996 January 29. The scenic tower was equipped with technical devices

of the baroque period, such as the wooden grating, the

2 MEASUREMENTS OF ACOUSTIC flies, and the wooden stage area. The orchestra pit ofPARAMETERS about 77 m2was filled with practicables in order to align

the floor with the stage during the symphonic per-Italian theaters are usually characterized by low rever- formances.

beration times and high absorption of the hall. These During the measurements, the proscenium was eom-circumstances create a suitable acoustic comfort for op- pletely empty, with the curtain open and without anyeras that were composed especially in Italy during the scenic arrangements on the stage (Figs. 1-3). Thesenineteenth century. Often Italian theaters are considered were the main geometric characteristics of the former"to sound" very well for operas, but to be too "deaf" theater:for music.

While during the last century Italian theaters were · Global volume 21 800 m3used to present operas exclusively, nowadays they are · Floor surface (main hall and balconies) 1480 m2also used for symphonic music. In that case, in a typical ° Total internal surface (lateral walls, floor, and ceiling)Italian theater the orchestra is located on the stage, and 7500 m2

it appears that the acoustics of the hall are not perfect ° Seats 819for this configuration. · Proscenium 13.3 m wide by 8.5 m tall

The Venetian Teatro La Fenice, while having remark- · Main hall, 19.0 m wide by 13.7 m high by 23.8 m longable acoustics with regard to operas, had some limitations ° Stage 27.5m wide by 28.2 m high by 18.6 m deep.

Fig. 1. Theater during measurements.

1052 J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December

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PAPERS ACOUSTICS OF 'LA FENICE'

added some absorption. Although in the past no mca-2.2 Measurement Technique surements had ever been made with the audience in this

The measurements in the empty room were made dur- theater, experimental results obtained by the authors inlng three days: 1995 October 14, 28, and November other similar Italian theaters show that the reduction in4. The absence of the audience was not particularly reverberation time due to the audience is less than 0.1important, as the seats were heavily upholstered, and s at midfrequencies.some of them were covered with a thin tissue, which The experimental setup used at the theater, shown in

Fig. 4, consisted of a blank shot gun, a dummy headm with binaural microphones (Sony DRW70C), and a DAT

recorder (Aiwa St-l). In the laboratory the impulse re-sponses were transferred digitally in.WAV files by usinga digital audio board (Multi!Wav Digital Pro) and thenanalyzed by using a wave editor (COOLEDIT 95) withhomemade extensions (AURORA) and a specializedsoftware (MLSSA 10.0C).

The basic measured quantities are 64-k-sampled longbinaural impulse responses, from which the acoustic pa-rameters are computed according to ISO 3382. A briefdescription of these objective parameters is given inSection 2.3.

The sound source was located exactly in the center ofthe proscenium, under the fire curtain. The recordingsof the gun shots were taken at 27 points, uniformlydistributed on the main floor and balcc,nies of the rightside of the hall (which was perfectly symmetrical), asshown in Figs. 5 and 6. Some additional measurementswere made to check the symmetry and the effect ofdifferent source positions. Fig. 7 shows the binaural im-pulse responses of a point in the middle of the main floor.

2.3 Acoustic Parameters

Since the first definition of reverberation time by Sa-bine [2], many acoustic parameters have been developedto describe the acoustic behavior of a hall. Accordingto the definitions contained in ISO 3382 [1], among thephysical parameters already defined, the following were

Fig. 2. Stage during measurements, chosen for the analysis.

Fig. 3. Main hall during measurements.

J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December 1053

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TRONCHINANDFARINA PAPERS

It is the first-order momentum of the squared pressure2.3.1 Tls, Tao impulse response, expressed in milliseconds.

Reverberation time calculated from the decay rangebetween -5 and -20 dB (Tls) and between -5 and 2.3.4 Initial Time-Delay Gap (rrDG)

-35 dB (/'30) on the integrated Schroeder curve, in Defined by Beranek [6], it is the delay of the firstseconds, reflection from the direct wave, expressed in millisec-

Schroeder [3] found that the reverberant decay can be onds. It is usually calculated directly from the impulsedescribed by a backward integration of the impulse response.response,

2.3.5 Interaural Cross Correlation (IACC)

I5(p2(t)) = N h2(x) dx (1) As suggested by Ando [7], it is the normalized correla-

tion coefficient between the first 50 ms of the pressure

where impulse responses measured at the two ears of the binau-ral microphone. From the definition of the cross-

(p2(t)) = time average of infinite number of decays correlation function, given byh2(x) = impulse response

]Eq. (1) can be written as lira ha(*) · hs('r + t) dl'T_oo 2-T T

p(,) =

[f: fo ] [l_f: fr ](p2(t)) = N h2(x) dx - h2('r)dx . (2) lira h2('r) da'. ha('r + t) d'r

T_0o 7-_ T -- T

Eq. (2) can he represented in a (p2, 'r) diagram, as shown (4)in Fig. 8. and taking into account that the limitations of the integral

are often 50 ms, the IACC is defined as the maximum

2.3.2 Early Decay Time (EDT) value of Eq. (4), that is,Since Jordan [4] demonstrated that the subjective per-

caption of reverberation is corrdated more strongly with IACC = ]p('r)]ma x (5)

the initial decay of the reverberant tail, he suggested to where 'r _< 1 ms.calculate the reverberation time from the decay rangebetween 0 and -10 dB on the integrated Schroeder 2.3.5 Strength G

curve, in seconds. It is the difference between the measured sound pres-sure level, and that produced by the same omnidirec-

2.3.3 Center Time ts tional source in a free field, at 10-m distance from itsIt was defined by Kfirer [5] as Schwerpunktzeit in center, and is expressed in decibels. It was defined in

the equation ISO 3382 and expressed by the equation

J: 'rh2('r)dx f,_°h2(,r) d,r- oo (3) G = 10 log _--_---- --. (6)Ts

[' h2(T)dT ' f hl2o('r)dT_o _o

...........-.......J......t .....L,_.l.......-.....

....................] .....l'.....l .....1--_"_ _-_,-_;'_........

' ' 't ! I IImlOul_esoume: ? --_ ¢l

blankshotga3 RIGHT--LEFTDATRecorder

Fig. 4. Measuring system of binaural impulse responses.

1054 J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December

/

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PAPERS ACOUSTICS OF "LA FENICE"

time interval is limited to 80 ms, whereas if the clarity2.3.7 glarheitsmass or Clarity Ceoand Cso is related to speech, the time interval is set to 50 ms.

It is defined [8] by the equation Reichardt, Abdel Alim, and Schmidt defined such an

acoustic parameter in order to relate the "transparence"

f S0ms of the music to an energetic parameter.h2('r) dx

C = 10 log ° o (7) 2.3.8 Speech Transmission Index (STI) and RapidI h2(_r)dM Speech Transmission Index (RASTI)"80ms

These parameters were defined by Houtgast andSteeneken [9]-[ 11]. They are computed from the values

When the clarity is related to musical perception, the of the modulation transfer function (MTF). This quantity

fZ

·......................_.........:....................:'Z.........._..........'_'"'""'"""L"_'_L .......

J

m BINAURAL RECEIVERS

Fig. 5. Sound source and receiver positions on balconies.

Fig. 6. Sound source and receiver positions in stalls.

J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December 1055

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TRONCHIN AND FARINA PAPERS

is defined by the ratio of the received modulation ampli-tude to the original modulation amplitude, making useof an excitation signal obtained by an octave-band ill-

tered pink noise, having an energy envelope (squared [ Illamplitude) slowly modulated at frequency F, as shown I I'iffFig. 9. h,l,,,l,,,,L,,,,,,,At the receiving microphone the sampled signal pre- ' ' ' -

sents an energy envelope with reduced modulation

depth. The ratio between the output modulation ampli- ' rg----I.L__L_ _o h2(r)drtude and the input modulation amplitude is the MTF, [_h'(r}l a1

Il/

re(F) - m°ut (8) _/min

The value of m(F) can be computed for each modula-

tion frequency F in one-third-octave, increments from . [-- ^ _[rJdr0.63 to 12.5 Hz, covering the range of the human voice 1modulations.Furthermore,theoctave-bandfilteredcar- 0 t

tier signal can be produced for any octave band from Fig. 8. Schroeder plot as represented by Eq. (2).

i:_..........Elle Edit ]Er_'a_orm Generate _pUons Elelp

i

656'_ Sam e_ Enalz_ K '_m. O:ffi01 488

Die gdt Ira_sform _-ienemte _pUons lJelp

'_ ......... --_=: __! ] _r_ .................. _ ;_g_

Fig. 7. Impulse responses at point n.20.

1056 d. Audio Eng. Soc., Vol. 45, No. 12, 1997 December

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PAPERS ACOUSTICS OF "LA FENICE'

125 Hz to 8 kHz. Thus a complete set of MTF valuesfor seven octaves is obtained. The STI is computed from 2.4 Discussion of Experimental Resultsthe seven MTFs. Fig. 10 shows that the values of Tis and 7'30(Ti5

Although the STI is an exhaustive acoustic parameter, 1.75). These values are well suited for operas and sym-describing the intelligibility of concert halls, Houtgast phonic music, with on average better results than thoseand Steeneken [11] found out that it was not necesary of other Italian theaters (for example, Milan's La Scala),to obtain a detailed set of MTFs to quantify the intelligi~ which sound often too "dry" for ensemble performances.

bility of an enclosed space. Hence they defined a shorter This is certainly one of the reasons for the good acousticparameter, the rapid speech transmission index reputation held by the La Fenice theater.(RASTI), limiting the analysis to a restricted number of In Fig. 11 the values of the early decay time and thedata. The procedure is very similar, but the carrier's center time are shown. The EDT value (EDT _ 1.25)

" frequencies are referred only to the octave bands of 500 is lower than Ti5 and T30, showing that the first part ofand 2000 Hz. the impulse response carries much more energy than the

The values of m(F) can be computed directly from late part. This causes the Schroeder integrated decaythe impulse response of a system, provided that it is curve to exhibit a double-sloped shape, with a fast initiala linear, passive, time-invariant system, as shown by decay, followed by a slowly decaying tail, as shown inSchroeder [12]. These hypotheses correspond to the as- Fig. 12. This behavior is useful in a multipurpose theatersumption of very little background noise, so that the because it produces good clarity and intelligibility formodulation depth reduction is due only to the room's

reflections, echoes, and reverberation. This assumption 38

is certainly met in this case, because the theater wasvery silent, and no external noise could affect the lis- 2.4tening conditions.

Since the effective signal-to-noise ratio is of no influ-ence, there is no problem employing a sound source Les

v-with a spectrum different from the normalized spectrum t2.defined in the original works of Houtgast and Steeneken

[9]-[11] or those defined in the new IEC 268-16 [13]. 0.eThe only problem connected with the use of an impulsivesource (a gun shot in this case) is the directivity of the

0.

source, which does not resemble the normalized direc-

tivity of the human voice since it is almost perfectly Frequemoy(Hz)omnidirectional. Furthermore, the recording of the im- (a)pulse response is not made with an omnidirectional mi- a I

crophone, but with a binaural one. These deviations are, ]to a certain degree, compensating reciprocally. Further- z4

J

more, the measurements under these conditions are prob-

ably more representative of the real listening conditions tsin a theater, where the listeners are always facing thestage while the speaker is moving around on it. 1.2.

To compute each value of m(F) from the impulseresponse h(t), an octave-band filter is first applied to theimpulse response in order to select the carrier's fre- 0.equency bandf. Then m(F) is obtained using the formula

0.

f: Frequency (Hz)h_('r)' exp(- j2_'r) dx

(9) (b)tn(F) = h_('r)d'r Fig. 10. Reverberation times in octave bands for La Fenice.(a) Tis. (b) T30.

1/F 1/F

°m _ Acoustic

system

time time

Fig. 9. Modulation of energy envelope at input and output.

O.Audio Eng. Soc., Vol. 45, No. 12, 1997 December 1057

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TRONCHIN AND FARINA PAPERS

speech and songs, while the musical performances can into account the temporal characteristics of a well-benefit from the liveness and blending caused by the known music piece, the Sinfonia Jupiter, K551, byhighreverberationtime. W.A. Mozart, which has an effective durationof the

Fig. 13 shows the map of strength G. It can be seen autocorrelation function % = 38 ms. The contour maphow the spatial distribution of G is quite uniform on the of Ando's preference index is shown in Fig. 19. Themain floor. Instead of the focalization, which affects values are high, ranging between - 1.5 and -0.5,many horseshoe-shaped Italian theaters, there is little which means that this room was perfectly suited for thereduction in sound level in the center of the rear part. kind of music represented by this % value.

The intelligibility index RASTI is distributed uni-

formly. The highest values were found in the seats close 3 COMMENTS AND CONCLUSIONSto the walls, as shown in Fig. 14. This is typical forthese positions, which benefit from wall reflections with The acoustic assessment of the former theater La Fen-a shortdelay, ice in Veniceincludedmany objectivemeasurements

The clarity, measured at S0 and 80 ms is more suitable to define the properties of this theater. The measures· for speech and operas than for symphonic music, being evaluated were reverberation time (Ti5, T30,and EDT),

around 0.24 and 3.8 dB, respectively (Fig. 15 and 16). center time ts, initial time delay gap (ITDG), interauralThe same holds for the center time ts, shown in Fig. 17, cross correlation (IACC), strength (G, level distribu-with an average value of 80 ms. tion), clarity (C80),and speech transmission index (STI).

The interaural cross correlation IACC_o,having values An analysis of the results showed the following.around 0.2-0.3, is quite low, ensuring a good spatial 1) Reverberation Time: The reverberation time T30impression and envelopment of the listeners (Fig. 18). showed an average value of 1.8 s with a regular distribu-This was certainly one of the better acoustic characteristics tion over the frequency range. This value is perfectlyof the theater, as usually it is difficult to have low values suited for operas and speech, while it seemed too lowof IACC coupled with high values of clarity, and it is well for symphonic music. The mean value of EDT is stillknown that a good spatial impression is the most important lower, showing that the initial slope of the decay isparameter for the overall musical acoustic quality, steeper than the subsequent tail. This is a favorable eon-

From the measured objective parameters the prefer- dition for a multipurpose theater, as the speech intelligi-ence index according to Ando's theory has been com- bility is not affected while the music is blended andputed by using a specialized homemade software, taking sustained by the reverberant tail.

2) Clarity and Center Time: The clarity and center

2'34 time values are optimal for speech and operas, but theyexhibit a sound field a little too defined for symphonicmusic, particularly for a certain kind of music character-ized by a low tempo and consequently a very long value

[ of the effective duration of the autocorrelation func-.8 III I tion 're.

'_1.! ___._. _____!ltt_3) IACC andlTDG:The IACCsoamounts to a value

of 0.25 at most positions. This is due to lateral reflec-tions. It ensures a good spatial sensation. The ITDG

o. values (ranging from 7 ms close to the walls to 25 msin the middle of the hall) confirm the benefits of lateral

_ _ _ _ _ _,_ _, _ _ _._o strong reflections.F,,q_.,_(_) 4) Strength: The distribution of the Strength on the(a) main floor is quite uniform. Maximum level differences

_40. of 6 dB are found, but typically they are only 2 dB. The

I horseshoe shape of the theater does not show a big focus

_20 effect because of the presence of absorption at rele-vant places.

_0o 5) STI: The uniform distribution of the STI (0.50-8o 0.60) is related to a fair to good intelligibility. This is

essential for an auditorium such as required for opera_60

use. The uniform distribution of the STI also indicates40 a uniform distribution in the temporal properties of the

hall. Close to the walls the STI value increased slightly.20 This effect is typical as reflections close to the wall0 increase the effective signal-to-noise ratio.

F_y (H=) The objective acoustical properties of the theater agree(b) quite well with the subjectivereputationof this hall,

Fig. 11. Early decay and center times for La Fenice. (a) EDT. which had been gained over a time period of more than(b).ts. 100 years.

1058 d. Audio Eng. Soc., VoL 45, No. 12, 1997 Decenllber

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PAPERS ACOUSTICS OF 'LA FENICE'

File: C:*_JSERS_LN'BER_ IC_12. TIIIFiltered Enerljg-Tlme Cm-ue - dB (1090 Hz, 4.99 octl

·' li10.0 j

0.0 [

lo .o j RI

20.0

30.0

40,0

_O.O

SO, 0

70.0

BO .0

90.0

auto

500.0 1000.0

Tine - nsec

CURSOR:y = -51.1637 x = 1486.9545 (65534)

(a)

Fil=: C:,I]SERS%__ IC]_IZ. ?IHFiltered Schroeder Plot - dB (1099 Hz, 1.CO oct) (c_p)

i

_0 ·0 {I

10.0 {

0.0 110.0

ao.o '_._......_..__'30.0

·40.0

50.0

60.0

'?0.0

·80.0

J" ' ' ' I I&uto

500.0 1000.0

Tins - nsec

T_ reuerberation time = 1.643 sm'cs(r = -0.999)

(h)Fig. 12. (a) Energy-time curve at point n. 12. (b) Schroeder plot at point n. 12.

10.00 ¸

5.00

000 ..___

-500

-10.00 X.x

-15.00 -10.00 -5.00 0.00 500 10.00 15.00 20.00 25.00

Fig. 13. Spatial map of strength O.

J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December 1059

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TRONCHINANDFARINA PAPERS

10.00

5.00

0.00

-5.00

-10.00 _

-15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00

Fig. ]4. Spatial map of RASTI.

I

10.00

5.00

0.00

-5.00

-15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00

Fig. 15. Spatial map of clarity C5o.

1

10.00 [

5.00

0.{30

-5.00

-10.00 _,

-15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00

Fig. 16. Spatial map of clarity Cgo.

1060 d. Audio Eng. Soc., Vol. 45, No. 12, 1997 December

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.A.E.S AOOU..,OSO.' F'"'C"

10.00

5.00 / _'_

0.00

-5.00

-10.00 _

-15D0 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00

Fig. l 7. Spatial map of center time ts.

5.00- i _' \

ooo :!-5.oo r_}}_._j/j

-15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00

Fig. 18. Spatial map of interaural cross co_relation IACCso.

I

10.00

5.00

o.oo _!!?i-iili!?i!;i i

-5.00 ¸

-15.00 -10.00 -5.00 0.00 5100 10.00 15.00 20.00

Fig. 19. Ando's preference' index S (Mozart's Sinfonia Jupiter, k.551, tc = 38 ms).

J. Audio Eng. Soc., Vol. 45, No. 12, 1997 December 1061

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4 ACKNOWLEDGMENT [7] Y. Ando, Concert HallAcoustics (Springer, Ber-lin, 1985).

Special acknowledgment is due to Giovanni Farolfi, [8] W. Reichardt, O. Abel Alim, and W. Schmidt,

who had to plan the acoustic chamber of the theater, "Definition und Me_grundlage eines objectiven Ma_esand to Alessandro Cocchi, who encouraged us to write zur Ermittlung der Grenze zwischen brauchbarer und

thispaper, unbrauchbarerDurchsichtigkeitbei Musikdarbietung,"Acustica, vol. 32, p. 126 (1975).

5 REFERENCES [9] T. Houtgast, H. J. M. Steeneken, and R. Plomp,"Predicting Speech Intelligibility in Rooms from the

[1] ISO 3382, "Acoustics--Measurements of the Re- Modulation Transfer Function. I. General Room Acous-

verberation Time of Rooms with Reference to Other tics," Acustica, vol. 16, pp. 60-72 (1980).Parameters" (1997). [10] H. J. M. Steeneken and T. Houtgast, "A Physi-

[2] W. C. Sabine, Collected Paper on Acoustics (Hat- cal Method for Measuring Speech-Transmission Qual-yard University Press, Cambridge, MA, reprinted by ity,"J. Acoust. Soc. Am., vol. 61, pp. 318-326 (1980).Peninsula Publishing, Los Altos, CA, 1993). [11] T. Houtgast and H. J. M. Steeneken, "A Multi-

[3] M. Schroeder, "New Method of Measuring Re- Language Evaluation of the RASTI-Method for Estimat-verberation Time," J. Acoust. Soc. Am., vol. 37, pp. ing Speech Intelligibility in Auditoria," Acustica, vol.409-412 (1965). 54, pp. 185-199 (1984).

[4] V. L. Jordan, "A Group of Objective Acoustical [12] M. Schroeder, "Modulation Transfer Functions:Criteria for Concert Halls," Appl. Acoust., vol. 14(1981). Definition and Measurement," Acustica, vol. 49, pp.

[5] R. Kiirer, "Zur Gewinnung von Einzahlkriterien 179-182 (1981).bei Impulsmessungen in der Raumakustik," Acustica, [13] IEC 268-16, "Sound System Equipment," part 16vol. 21 (1969). retitled, "The Objective Rating of Speech Intelligibility by

[6] L. Beranek, Music, Acoustics and Architecture the Speech Transmission Index," Redraft, International(Wiley, New York, 1962). Eleca'otechnical Commission, Geneva, Switzerland (1988).

THE AUTHORS

BI

L. Tronchin A. Farina

Lamberto Tronchin was born in 1964 in Preganziol, studied at the University of Bologna, from which heTreviso, Italy. He studied at the University of Bologna, received an engineering degree (1982) and aTPh.D. infrom which he received an engineering degree (1992) technical physics (1987). He was a researcher at theand a Ph.D. in technical physics (1996). He also studied University of Bologna from 1986 to 1992, and thenpiano at the Conservatorium of Ferraraand Venice. transferred to the University of Parma. He has worked

Dr. Tronchin is involved in researchon room acoustic in many areas of acoustics, ranging from vehicle com-simulation and measurements of concert halls (3-dimen- partment sound fields to room acoustics (theaters).sional IRs using B-format techniques). He is also working During the last few years, Dr. Farina has developedon psychoacoustics andhas attended the Institute of Sound new computation algorithms and measuring techniques,and Vibration Research, Southampton, UK, as a visiting including the Pyramid Tracing program Ramsete. Otherresearcherto investigate the correlationbetween subjective relevant contributions include work on finite-element nu-evaluations and objective measurements. He is also work- merical models, outdoor propagation of road and training on musical acoustics, such asexamining piano tonings noise, impactof environmental aircraftnoise on communi-and the sound energy properties of flutes, ties, new measurement techniques of the absorption coef-

Dr. Tronchin is the author of about 30 scientific publi- ficient in standing-wave tubes, in-situ medal analysis ofcations, and is a member of the Italian Association of rotating disks, and subjective and objective evaluation ofAcoustics, and a member of the coordinating committee the acoustic quality of concert halls. He has studied MLSof the musical acoustic group of the Italian Association impulse responsemeasurements and fast convolution tech-of Acoustics. niques, and is now mainly involved in the field of acoustic

virtual reality and underwater acoustics. Dr. Farinais the· author of over 100 scientific publications. He is a member

Angelo Farinawas born in 1958 in Parma, Italy, and of the AES and of the Italian Association of Acoustics.

1062 J.AudioEng.Soc.,Vol.45,No.12,1997December