3 r Suund ä$ än ü$tillati ün

zö1

44ü

418fi

:,"3 {{l

77 rm

8L r$ffr

r $nrne cues äb$ut freeuenties änd wavelengths

lnfraEaunds

Lcwest nate*f ths p*ana

{A*y f A-2}

h/liddle C {Cz /t4!

Mtddfe A

tÄ3 / A41'

Highest nstesf the planc

l{7 I cxtr1

U lträE*unds > ä#üü$ d 27 rfim

4 ff $uperpüsitiün pri n#plelntsrferänceg

* Th* pr*ssLir# #n th**in#s is #r#trt*r thffirT

r,*t''ffis *nily #ffi* . #LJrttr

{cmffistru*tfrrr*intsrfsrffinrffisl

r'*dif thtrrtr

i i;i;e, i i'; ji'i ,ir.r It$.l +i1 t .q,-tf'-{,u$'*.=i.:,= ,

Th e interferrnre päfterndepends sn freüuenry ändd istä nce between süurres

) $peed *f$peäd sf sound

Är'*ll*tir" hl t"ltx{}ll llr

7, ffi Spesd $f $suftd

t $pesd af s$und in ather rnaterials

Air

*rass

St sl

C*nrrete

lÄJ**d

Watsr

,#v{

.''iII s^'

..-+ t'. *".? , Tir'!-i -'",.{

d

I.t

'c l,+:'{i .*-H v'

{"z{34

s:.

3ä$ü.

33üü.

3.4

Fundamentals of Acoustlcs !The Soundke

üutiltne

,4st,.u" ri

c r',

L r What is ä snund wäve ?

Z r speed of süund

3 - Sound as an üscillati 0n

4 r 5uperpüsitfün principle

5 - Süund pressuil"e level

6 r Distance law

,r4

{r-

II4

c7 L,

vl,t' !JI//

f:i'i

7. ffi Speed of soundI Srsed sf $$Hnd is n$t $sund pärticle uelucity II, r:ttgifrxlini*il l1tftr'*

*>The pärttnl*s äre üsciNlating with a väriahleveilscity {a.k,a* "*ressure grädient"} ärüund astable positi *n {if there's n$ wind in cäse nf nir f }

ffiüF Th* i..j1'.'":ji*;ri: is travglllng frorn lgft to right at thespeed af s$und

S ff Ssund pr*s$ur€ Lguel il r#fgrsfit*s

.fet flngiil]s at l,##rn

dn wLL4ü

23*TZ*

Fsp ür*up

Heavy Truck

t*nvürs*tian*lSpcech

Lihrary

Sedrasm

Thträsh*ld sf

F*rest

Vuvureln at lrn

Jack hsffirrler at 3.m

Auerägß

Strset Traffic

Susin*ss *ffice

Living Rsoffr

11*

"##g#

ss7#

##

s#4#

fr#

z#1ff

*heäri*s at äkHe

Psychoacoustlcs LThe ear

ffi*cund?ryäTt

sardrunTf

K

sudittlryfr#rYts

st{

#\ cochlsa

t*SFk *.*ft

I r The physits sf ths sär

iTh* ürgän of Csrti has tiny hairs tälled hair t€llr:i

iyyrhich rülc iE tn tränsforfn the vibrati*n intcinerve impulses

7r Hearins dailnäges

ürgän nf tcrti tof ä rn*usclin günd üünditifin

The särn* after än *xpüsurrto ä very Inud

iTh* hair tells rän hardly r*genrräte: whenIth*ynre darriäg*d, its finished

xF Froteut yüur rärs !

t'lülst

Er&tr!?*

Psychoacoustlcs 2Percgption of loudness

üutililne

1, - Weber-Fethner Law

7- Absulute Threshold of heäri ng

3 r Equal-lüudness contours

4 - Just-noticeable differences for loudness

5 n Threshsld of hearing and cürnplex sounds

6 r Esti mati ng loudness

1 r Weheil'-Fechiler Lawä3

ffi',-;'i-**;

'-j\*,-::i;'l

f*

Fr-+ss ffi ?**ü P*ffixl$ =Fn+r.q

= Züüüü P* xl$ ]**., = ZüütX]ü p{ri ,- f{#d

i

i

L;$f,f. # ttütlQu* -+.u:1 i:;iä,i .,,,. L*u* : lüürJ#**ot,.

...as bgtwggn2ü00ü Pa and

?üüüü0 Fa

' .., but the perception is roughly propürti onal tothe dB scale -> That's why the dB is so used !

i

l*r* = St) rJ'ff*",n .$-;; i; u't il,l ,.,.,,.tt"t'.

,.:..., i .,.. :=.:l':""+

There is pet septually äs

rnuch dilfference hetween2üü* Pa and 200üü Fä...

ffiq3 *tlg,lg

ü 4tl{;vl.ä,1

*-i

r.F- ?n*E> t'q+l LJ

7 r Absoilute Threshoild of heärt ng

The threshsld sf hearilng is the average level in dB

SPL af the süftest pure toile that humans cän

detect, for eäch frequeilcy

' Note theeffect of age(20,40, soyears) $n thethreshaild

-;fl J ,".. I

$"*5 *.1L ., t L J i

ü";t]"5ä?5freülil*r?{y *f tesf t*rre {kr*ri

I.1 .

1$ü.üä ;ü

**T:iräroold af pä

,-- \rra

13fr;5t3{1Ifü1-r{--t

:'1-L}

if*l*{rad

. {}, tll., ffi,tb,*Ft:ryq

-f

ttfireshold I

3 n Equäil-loudness contours

13ü

1äü

11ü

-n* 1 üüJ*süä80g7üürJfiilE

H 5t]ü)

E4Ü{L

E3üääüU'

1ü

ü-1ü

1 $ü* 1ü*k Freq uency tHt)

5 z Effect uf sgund durätiürlBelnw 0,ä s., the lnnger the sound, the lnuder it willhe perceived

Beyünd 0.2 s., the lüudness is slishtly reduced

5 n lVl äskilngthre$h$ldlf twc tnnäs äre slmultäneously presf,ntsd tn th* sär, theptrt€ptisn of the safteEt tan€ rnäy be rnäsked by the lcudsst

Wdtrf{fffifud trlt'ffirffit rfoiä* W tffrfrffin * kfiäl

Lsudn ess Irnax loudness

1$S

t

#,#

Saund durattün {s}

#,? ü,ä s,-3 ü,4 s,5 #,#

1:\

\i

{$

1q

,1'

'$'-.--

\, , l--*'' -F..

.jF. ,-*{$

Jd.d,A' ) j

ü'ä #,s 1 2Fr*qü*ffiä f lrl-le

ffilel

;ssffi

frl*#ss{,#?#tü

#4sIr#s&fr,äafr{tt

s-c#s

tlnsä *,üs üut TS ä$

S n Isti ffitatins lsudnes$Serailse of the frequ*ncy dependenc*, the directrrsasure nf thc s$und pressure level in dß 5f L is nnttünv#ni*nt to esti mate laudnessThus it is ilec*ssäry ta apply ä freqstncy torrscti$nbeforc mräslrring the SpL, that shoilld dep*nd ünloudness r A*weighfinS prüvides ä

rneäsurä in dä4, and isd*signed fcr environ rnenta I

n*ises* {*weighti ng prüvides a

rneäsur* in dBC, and isdesigned fsr lcud nciEes

{a irt raFt, etc... }

E nglis ch- D euts ch Vokab elliste

English DeutschOscillation Schwingung

Root Mean Square (RMS) EffektivwertSound pressure Schalldruck

Sound particle velocity ( =(( pressure gradient u)

Schallschnelle

Sound pressure level (SPL) Scha lld ruckpegelSound wave Schallwelle

Speed of sound Sch a I leeschwi nd igkeit

E nglis ch- D euts ch Vokab elliste

Enelish DeutschEq ua l-loud ness contou rs Ku rven gleicher La utstä rkepegelThreshold of heari ng Hörschwelle

Threshold of pain Schm erzschwelleUltrasound Ultraschalllnfrasound lnfraschallLoudness Lautheit

Masking effect Maskieru ngseffekt