Beyond the visual. The acoustic reconstruction and simulation of ancient senate sessions

Dr. des. Christian Fron University of StuttgartDepartment of ancient historyAbteilung Alte Geschichte06. January 2016

Introduction

outline

1. short introduction

2. the curia Iulia as research project

3. An acoustic simulation: our approach

4. results and further questions

the curia Iulia as research project

• 52 BC: The senate building burns and P. Clodius Pulcher with it. • By no later than 45/44 BC and in the context of the construction of the Forum Iulium a

new Curia is enacted.• 29 BC: The curia Iulia is dedicated by Octavian, the later Augustus.

the curia Iulia as research project

the curia Iulia as research project

the curia Iulia as research project

the curia Iulia as research project

“1. The treasury, prison, and senate house ought to adjoin the

forum, but in such a way that their dimensions may be

proportionate to those of the forum. Particularly, the senate house

should be constructed with special regard to the importance of the

town or city. If the building is square, let its height be fixed at one

and one half times its breadth; but if it is to be oblong, add

together its length and breadth and, having got the total, let half of

it be devoted to the height up to the coffered ceiling.

2. Further, the inside walls should be girdled, at a point halfway up

their height, with coronae made of woodwork or of stucco.

Without these, the voice of men engaged in discussion there will

be carried up to the height above, and so be unintelligible to their

listeners. But when the walls are girdled with coronae, the voice

from below, being detained before rising and becoming lost in the

air, will be intelligible to the ear.” (Vitr. 5,2,1f.)

the curia Iulia as research project

[17,75 m (w) + 25,63 m (l)]/2 = 21, 69 m (height according to Vitruvius).approximate real height: 23,40 m

outline

1. short introduction

2. the curia Iulia as research project

3. An acoustic simulation: our approach

4. results and further questions

An acoustic simulation: our approach

http://www.odeon.dk/

http://www.odeon.dk/archaeological-acoustics-open-theatre#

An acoustic simulation: our approach

13

reflexion of sound

barrier (f.i. wall)sound wave

14

absorption of sound (decreased reflexion of sound)

barrier (f.i. wall)

15

transmission of sound (sound absorbtion)

barrier (f.i. wall)

16

reflexion + transmission

f.i. window

lower frequencies

higher frequencies

An acoustic simulation: our approach

view inside of the Curia

1: benches

2: entrance

3: niches

4: cornices

5: windows

6: coffered ceiling

7: open space before the door

An acoustic simulation: our approach

Absorption coefficients

Frequency (Hz)63 125 250 500 2000 8000

Alp

ha

0.96

0.8

0.64

0.48

0.32

0.16

14501 Alpha aus Margfedc

4035 Plaster, gypsgfedc

11050 Personen, im gfedcb

1005 Smooth brickwgfedc

10003 Double glazingfedc

107 Concrete blocgfedc

4036 Plaster, gypsgfedc

1 100% absorbengfedc

Odeon©1985-2015 Licensed to: Fraunhofer-Institut für Bauphysik, Germany

An acoustic simulation: our approach

Speaker P (cross)

P1: podium (active)

P2: groundlevel aisle

P3: first step

audience (blue points)

M1: Podium

M2: in front on first step

M3: middle on first step

M4: middle on groundlevel

M8: in a corner

M5: 1 m in front of the door

M6: 4 m in front of the door

M7: 8 m in front of the door

outline

1. short introduction

2. the curia Iulia as research project

3. An acoustic simulation: our approach

4. results and further questions

results and further questions

Situation resp.Sound source distance Sound pressure p

in PascalSound pressure Lp

in Dezibel

Disco 1 m 2 Pa 110 dB

Hearing damage if heard for a longer

time

ear ab 0,36 Pa 80 dB

Main road 10 m 0,2 – 0,63 Pa 75 dB

TV 1 m 0,02 Pa 70 dB

Dialoge partner(normal

conversation)1 m 2 · 10−3 – 2 · 10−2 Pa 55 dB

Very quiet room ear 2 · 10−4 – 6,3 · 10−4 Pa 45 dB

breathing ear 6,32 · 10−5 Pa 10 dB

results and further questions

Redner P1 (emperor, red cross): ca. 56 dB (A) on 1 m

Ist: actual state; door closed. With cornices

OG: without cornices; door closed.

TO: door opened; with cornices.

Pos. SPL dB (A)Ist/OG/TO

STIIst/OG/TO

M1 64.6/64.6/64.6 0.85/0.86/0.86

M2 53.1/53.0/52.9 0.52/0.51/0.52

M3 53.1/51.2/50.9 0.46/0.45/0.47

M4 51.6/51.4/51.4 0.37/0.35/0.37

M8 51.1/51.5/50.3 0.50/0.45/0.45

M5 (1m) - / - /46.8 - / - /0.40

M6 (4m) - / - /43.1 - / - /0.38

M7 (8m) - / - /39.3 - / - /0.38

average 0.46/0.44/0.45

0 8 16 24 32 40 metres

0

5

10

15

20 metres

P1P1P2

P3

P11

3

2

333

4

3

5

3

6

3

7

3

8

3

P1

Odeon©1985-2015 Licensed to: Fraunhofer-Institut für Bauphysik, Germany

results and further questions

Speaker P2 (red cross): ca. 56 dB (A) bei 1 m

Ist: actual state; door closed. With cornices

OG: without cornices; door closed.

TO: door opened; with cornices.

Pos. SPL dB (A)Ist/OG/TO

STIIst/OG/TO

M1 54.8/54.5/55.0 0.56/0.57/0.55

M2 57.4/57.2/57.3 0.66/0.68/0.67

M3 51.2/51.1/50.9 0.41/0.38/0.42

M4 53.2/53.0/52.9 0.46/0.46/0.47

M8 50.7/50.8/50.8 0.44/0.41/0.51

M5 (1m) - / - /47.0 - / - /0.42

M6 (4m) - / - /43.5 - / - /0.41

M7 (8m) - / - /39.0 - / - /0.39

average 0.51/0.50/0.52

0 5 10 15 20 25 30 35 metres

0

5

10

15

20

25 metres

P2 1

2

3

4567

8

P2

Odeon©1985-2015 Licensed to: Fraunhofer-Institut für Bauphysik, Germany

results and further questions

Speaker P3 (red cross): ca. 56 dB (A) bei 1 m

Ist: actual state; door closed. With cornices

OG: without cornices; door closed.

TO: door opened; with cornices.

Pos. SPL dB (A)Ist/OG/TO

STIIst/OG/TO

M1 51.9/51.9/51.8 0.45/0.43/0.45

M2 52.5/52.4/52.4 0.50/0.49/0.51

M3 53.3/53.2/53.0 0.52/0.52/0.53

M4 54.7/54.7/54.5 0.59/0.59/0.6

M8 51.4/51.5/51.2 0.46/0.45/0.46

M5 (1m) - / - /47.2 - / - /0.43

M6 (4m) - / - /43.9 - / - /0.46

M7 (8m) - / - /41.4 - / - /0.52

average 0.50/0.49/0.51

0 8 16 24 32 40 metres

0

5

10

15

20 metres

P3

P1P2

P3P3

1

3

2

333

4

3

5

3

6

3

7

3

8

3

P3

Odeon©1985-2015 Licensed to: Fraunhofer-Institut für Bauphysik, Germany

results and further questions

speaker 2

listener 1 (emperor),

Free field

emperor

P2P1

P2

P3

P2112

1

3

1

4

1

5

1

6

1

7

1

8

1P2

Odeon©1985-2015 Licensed to: Fraunhofer-Institut für Bauphysik, Germany Restricted version - research and teaching only!

Thank you very much for your attention.

Thank you very much for your attention.

Reference:• Background: modification of the fresco of Cesare Maccari „Cicéron dénonce Catilina“• Slide 2: http://

www.digitales-forum-romanum.de/wp-content/uploads/2014/03/A-8-0201_JKLMNO_Curia-Iulia_Kontext.jpg• Slide 4: http://

www.digitales-forum-romanum.de/wp-content/uploads/2014/03/7-Phase-G_Sp%C3%A4te-Republik-I_Draufsicht.jpg and http://www.digitales-forum-romanum.de/wp-content/uploads/2014/02/7-Phase-L_Augusteisch-II_Draufsicht.jpg

• Slide 5: http://www.digitales-forum-romanum.de/wp-content/uploads/2014/03/A-10-0201_EFGH_Curia-Hostilia_isometrisch.jpg and http://www.digitales-forum-romanum.de/wp-content/uploads/2014/03/A-11-0201_I_Curia-Cornelia_isometrisch.jpg and http://www.digitales-forum-romanum.de/wp-content/uploads/2014/03/A-12-0202_JKLMNO_Curia-Iulia_isometrisch.jpg and http://www.digitales-forum-romanum.de/wp-content/uploads/2014/03/A-13-0202_PQRS_Curia-Diocletiani_isometrisch.jpg

• Slide 6: http://www.acsearch.info/image.html?id=1713375

• Slide 7:http://dlib.etc.ucla.edu/projects/Forum/assets/media/reconstructions/CuriaIulia_1/CuriaIulia_1_Inside_HiRes.jpg and http://www.jeffbondono.com/TouristInRome/RomeImages/IMG_1592-IMG_1595-20131006.jpg and image by google earth

Thank you very much for your attention.

Reference:• Slide 9:

http://farm8.staticflickr.com/7102/7356011222_724dc4d7a4_b.jpg• Slde 11:

Odeon-Model of the Curia Iulia from the Fraunhofer Institute of building physics and acoustics by Xiaoru Zhou • Slide 12:

Google SketchUp model of the Forum Romanum from the Fraunhofer Institute of building physics and acoustics by Xiaoru Zhou

• Slide 13-16: Slides by Prof. Dr. Philip Leistner

• Slide 17: Odeon-Model of the Curia Iulia from the Fraunhofer Institute of building physics and acoustics by Xiaoru Zhou

• Slide 19: Odeon-Model of the Curia Iulia from the Fraunhofer Institute of building physics and acoustics by Xiaoru Zhou

• Slide 21: http://www.welt.de/print-welt/article334313/Vom-Ticken-der-Uhr-bis-zum-Presslufthammer.html and http://www.fohonline.com/images/stories/15/02/current-foh/techfeature/intelligibility%20scale.jpg

• Slide 22-25:Additional Model and acoustic simulations from from the Fraunhofer Institute of building physics and acoustics by Xiaoru Zhou