architectural acoustics i

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Dr. Hani Obeid

Faculty of Engineering

Applied Sciences University

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Introduction and History

Dr Hani Obeid - Applied Sciences University 2

The arts of music, drama, and public discourse have

both influenced and been influenced by the acoustics

and architecture of their presentation environments.

It is theorized that African music and dance evolved

a highly complex rhythmic character rather than the

melodic line of early European music due, in part,

to its being performed outdoors.


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GREEK AND ROMAN PERIOD (650BC-AD400)

The origin of music, beginning with some primeval song around

Ancient campfire, is impossible to date. There is evidence tosuggest that instruments existed as early as 13000 BC. The

understanding of music and consonance dates back at least

To 3000 BC, when the Chinese philosopher Fohi wrote two

Monographs on the subject.


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GREEKS


The Greeks due to their democratic form of government

Built some of the earliest outdoor amphitheaters.

The seating plan was in the shape of a segment of a

circle, slightly more than 180 degrees, often on the

side of a hill facing the sea.

Example: Greco-Hellenistic theater built at Epidaurus

In the northeastern Peloponnese in 330 BC. The

Slope is 2:1, with 17000 seats


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ROMANS


Followed Greek seating pattern.

Limited seating arc to 180 degrees.

They added: stagehouse behind the actors, raised

acting area, and hung awnings overhead to shadeThe patrons.

The chorus spoke from a hard-surfaced circle (orchestra)

At the center of the audience.

Romans were better engineers than Greeks, and due toTheir development of arch and vault, were not limited

To building these structures on the natural hillsides.


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Roman Theater

At Aspendus,

Turkey


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EARLY CHRISTIAN PERIOD (AD 400-800)


This period is dated from Roman emperor Constantine

To the coronation of Charlemane in 800.

Example: the basilican church of St. Peter in 330


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The Basilcan church

Of St. Peter in Rome


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EASTERN ROMAN EMPIRE


Architectural features: domed roof to cover square

or polygonal floor plans. This form was combined

with classical Greek columns supporting the upper

walls with a series of roof arches.Example: St. Sophia (532-537) Hagia Sophia, or

Divine wisdom in Constantinople.


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St. Sophia Church

In Constantinople


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ROMANESQUE PERIOD (800-1100)


Romanesque style is characterized by rounded arches

and domed ceilings that developed from the spherical

Shape of the east into vaulted structures in the west.

The narrow upper windows, used in Italy to limit sunlight

Lead to larger openings in the north to allow the light,

And the flat roofs of the south were sharped in the north

To throw off rain and snow.

They are massive structures until the introduction of

Buttresses, which allowed the walls to be lightened.

Construction materials were brick and stone and pottery.


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Exception was St. Marks Cathedral

In Venice


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GOTHIC PERIOD (1100-1400)


Norte Dame Cathedral, Paris


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Renaissance period (1400-1600)


Started in Italy.

Development of new music.

Construction of churches.

Michelangelo.Starting construction of theaters.

Example:

Teatro Olimpico, Vicenza, Italy.


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BAROQUE PERIOD (1600-1750)


30 years war (1618-1648)- weakening of Hapsburg empire

And rise of France.

Italy became a center of art and music.

In northern Italy a style, which became as the Baroque (afterthe Portuguese barocco, a term meaning a distorted pearl

of irregular shape), grew out of the work of a group of

Flouentine scholars and musicians known as the Camerata

(from the Italian camera, or chamber).

Construction of Baroque theaters.Construction of Italian Opera Houses.


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Theatro Farnese, Parma, Italy


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CLASSICAL PERIOD (1750-1825)


Rousseau, Montesquieu, and Voltaire reacted to social

Conditions and establish universal right of man.

Classical music by Bachs son, Joseph Hyden, Mozart,

and Beethoven. They composed pieces with formalConcert hall performance in mind.

In London Hanover Square Room was built and Hyden

Conducted his London Symphonies in it.


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Hanover Square Room, London


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At that time the center of music was shifted from

Italy to London, Paris, Mannhein, Berlin, and Vienna.

Concert halls in these cities were available

To composers from all nationalities.

In Italy, opera was the cultural center of the world and

Opera-house design had developed slowly over two

Centuries. In 1778 La Scalla opened in Milan.


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La Scala OperaHouse in Milan


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La Scala OperaHouse in Milan


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ROMANTIC PERIOD (1825-1900)


Romantic music is more personal, emotional, and poetic

Than the Classical and less constrained by a formal style.

The Romantic composers wanted to describe thoughts,

Feelings, and impressions with music, sometimes evenWriting music as a symphonic poem or other program to

Tell a story.

As musical instruments increased in loudness they could

Be heard by larger audiences, which in turn encouragedLarger concert halls and the use of full orchestra.


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WAGNERS OPERA HOUSE


Wagners Opera House was built in 1876 in Germany

The Festspielhaus in Bayreuth.

It was the first theater to be built in close cooperation

Between the composer and the architect.The auditorium is rectangular but it contains a

fan-shaped seating area.


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Wagners Opera House


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Wagners Opera House


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MODERN ACOUSTICS


The nineteenth century produced the beginnings of the

Study of acoustics as a science and its dissemination in the

Published literature via technical books and journal.

Hermann von Helmholtz (1821-1894) published his book

Sensations of Tone in 1860, thus established acousticsAs science.

In 1877 John W. Strutt, Lord Rayleigh published the first of

His two volume set, Theory of Sound.

In 1874 Siemens patented the moving coil transducer,which led to todays loudspeaker.

* Alexander Graham Bell invented the telephone.


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In 1877 thomas Edison invented the phonograph,and in 1891 invented a motion picture.

In early twentieth century, the theorical beginnings

of architectural acoustics were started by W.C. Sabine.

He started his work to solve difficulties in the then new

Fogg Art Museum auditorium. This led to a well-known

Formula called Sabine Formula for the calculation of

Reverberation Time.


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Architectural Acousticsmay be defined as the technology of designing

Spaces, structures, and mechanical equipment to

meet hearing needs.32Dr Hani Obeid - Applied Sciences University


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[Hz]

Frequency

Wave length is the distance the sound travel in one cycle.

[m]



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Mathematical definition of dB

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If

By definition:

Where: N = antilog

b = baseX = logarithm

The followings are valid:

Dr Hani Obeid - Applied Sciences University


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Logarithm to base 10 is called common logarithm

Logarithm to base is called natural logarithm.

By definition the dB always describes a ratio of

Two quantities that are most often related to power



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Sound intensity

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The intensity I, of a sound wave is defined as the meanValue of the acoustic energy which crosses a unit area

Perpendicular to the direction of propagation in unit time.

c is characteristic impedance of sound, unit

is Rayl and is equal to 410 Rayl for air.



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Sound intensity in free field



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architectural acoustics i

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