Simula ed Acous ic Field in Mudeja -Go hic Chu ches
M. Galindo’, T. Zama ezo’, S. Gi &, J. J. Send a’. and J. Na a o’
‘Depa men o Applied Physics, ‘Depa men o A chi ec a al Cons uc ions.
Se ille Uni e si y. A da Reina Me cedes. 2; 41012~& illa (Spain)
Summa y: In his wo k we ha e unde aken an acous ic simula ion o he sound ield in se e al chu ches in he
ci y
o Se ille. The simula ion has been ca ied ou h ough he RAYNOISE p og am and has been based on he
e e be a ion imes measu ed in dmse space?.. We ha e ocused on Sound Ressu e Le els SPL, Cla i y C80 and
De ini ion D50 indices da a in ela ion o hei spec al a ia ions and spa ial dis ibu ions and hei compa ison
wi h he expe imen al alues.
INTRODUCTION
Mudeja s yle is a link be ween Islamic a and wes e n Ch is ian a , so i is a uniquely
Spanish a is ic mo emen . These chu ches we e p obably buil be ween he hi een h and
i een h cen u ies and hey we e buil o b ick. All he chu ches analysed ha e simila
a chi ec u al ea u es: h ee na es co e ed wi h wooden amewo ks ollowing in he Moo ish
s yle and a aul ed p esby e y. Send a e al (l-3) ha e poin ed ou ha he smalle size o hese
chu ches and mainly hei wooden ceilings signi ican ly imp o e hei acous ical beha iou , as
a as his can be indica ed by e e be a ion imes, o e he Go hic con empo a ies. The g ea e
abso p ion in he ceilings ends o lead o a dec ease o he g ea e e be a ion imes expec ed in
hese la ge olumes, abo e all a low equencies.
Besides being used o wo ship which implies he use o speech and music, hese buildings
a e some imes eno a ed and used as lec u e halls, hea es, o audi o ia. Acco ding o he
specialis Angulo (4), his ype o chu ch is called “ he Se ille pa ish ype”.
OBJECTIVES
Ou main aim in his wo k is o show he ag eemen be ween he expe imen al da a and he
simula ed esul s pe o med by he ay acing me hod (RAYNOISE e sion 2.la) in his ype o
a chi ec u al enclosu es. We a e specially in e es ed in esea ching he abili y o he so&wa e o
p edic he spec al a ia ions and spa ial dis ibu ion o he measu ed acous ic pa ame e s. We
mainly ocus on he SPL and on he acous ic indices C80 and D50. The measu emen es s as
well as he simula ions ha e been ca ied ou inside he unoccupied chu ches.
GENERAL+ ASPECTS
Using an i e a i e p ocedu e we ha e adjus ed he abso p ion coe cien s o he di e en
wooden ceilings, which a e he mos singula ones, un il we ob ained he simula ed e e be a ion
imes in a ange o +lO% o he in si u expe imen al esul s (see able 1). Those abso p ion
coe icien alues a e con as ed wi h o he simila da a in he bibliog aphy.
The geome ical and acous ical model is buil in his way and he whole simula ion p ocess is
execu ed wi h maximum o de o e lec ion R equal o 10. The numbe o ays N is de e mined by
he speci ica ions o he pmg am use ’s manual by he o mula 1256,6 1’ N’< S, wi h 1 he mean
ee pa h (m) and S, he cha ac e is ic su ace (m’) o he geome ic model. To decide when o
abandon a my, in addi ion o he o de o e lec ion, we use a dynamic ang o 60 dB and a ime
window, ollowing he manu ac u e ’s sugges ion, &,0294 1 (s).
Calcula ions ha e been ca ied ou using he Conical Beam Me hod (CBM) and we ha e
conside ed he ai abso p ion and he sound eloci y a he a mosphe ic condi ions o 20°C and 50%
ela i e humidi y, simila o ha a he measu emen ime.
The backg ound noise in each simula ion p ocess coincides wi h he measu ed noise spec a.
Likewise we ha e made calculus modi ying he di usion condi ions o he ceilings and audience
zone. This does no ha e a ma ked e ec on any e alua ed pa ame e s in he same way as Lam (5)
has al eady poin ed ou .
An omnidi ec ional sou ce wi h he known sound powe spec um o he eal one has been
used o ob ain simula ed sound p essu e le els. Bo h calcula ion op ions, image and mapping, ha e
been se o ob ain he acous ic pa ame e s implemen ed and o compa e wi h he expe imen al da a
Recei e su aces and mic ophones ha e been placed a 1,20 m abo e loo le el.
TABLE 1: Measu ed e e be a ion ima Tms and S~IIIU~&~ TSim
San a Ma ina San icen e San a Ca alina
F eq. (W Tmas TS i Tmcas
TSh Tmas TSi#ll
250 3,62 3,71 1,71 1,70 I ,50 1.48
500 3396 4.11 1,81 1.79 1,72 I,64
IO00 4,00 4.01 1,82 1,78 1.75 1.68
2GQo 3.57 3,70 1.68 I,70 I,67 1.57
4000 2,62 2,68 I,40 I,45 I ,45 I,36
RESULTS AND CONCLUSIONS
Figu e 1 shows a iew o he 3D model c ea ed o San Vicen e chu ch. Figu e 2 shows he
measu ed and compu e calcula ed alues o he sound p essu e le els ( ela i e o ha p oduced by
he sound sou ce in a ee ield a 1Om) e sus sou ce- ecei e dis ance a 500, and 2000 Hz oc a e
FIGURE 1.3D model used o simula ions in San Vicen e Chu ch
- - Adjus men
1 Cm) (ml
FIGURE 2. LpLp e (dB) e sus dis ance (m) a 500 and 2ooO Hz oc a e bands o San Vic&e chu ch.
(m) 1 (ml
FIGURE 3. C80 (dB) e sus dis ance (m) a 500 and 2000 Hz O&W bands o San Vic&e chu ch.
bands in his chu ch. The same g aphics show he heo e ical cu es ob ained h ough classical
di ise ield model, Ba on’s modi ied model (6) and an adjus ed cu e o he expe imen al esul s.
As we can see he simula ed le els con inue o dec ease u he we go beyond he c i ical
dis ance acco ding o Ba on’s model, bu he measu ed alues di e app eciably om expec ed
heo e ical le els al hough he same endency sugges ed by Ba on’s modi ied model o a enua ion
by dis ance is obse ed.
Simila ly igu es 3 and 4 compa e he measu ed and simula ed alues o C80 and D50
espec i ely as a unc ion o dis ance a he same oc a e bands. In bo h cases we
supe imposed
(con inuous line) he alues om Ban-on’s modeL Bo h se s o alues show simila spec al and
spa ial pa e ns, and hey show hese wo acous ic quali y desc ip o a e a he sensi i e o local
a ia ions, he e being no ag eemen wi h he p edic ed heo e ical model.
Qui e a sa is ac o y ag eemen be ween measu ed and simula ed esul s has been achie ed by
RAYNOISE compu e simula ion, mainly o he ea ly o la e ene gy indices in hese complex
ooms. In his espec i is use ul o emembe he unce ain ies ha a ise om he ep oducibili y o
measu emen s and absolu e posi ions o mic ophones in a eal chu ch and i s model desc ip ion (7).
a 5 10 15 20
25 30
35 0 5 10 I5
2” 25
3”
35
(ml Cm)
FIGURE 4. D50 (%) as a imc ioa o dis ance (m) a 500 and 2000 Hz oc a e bands o San Vicea e chu ch
We ha e op imised he simula ion p ocedu e aking in o accoun he measu ed e e be a ion imes,
so he simula ion p ocess can be used in his way o imp o e any emodeling p ocess om an
acous ic poin o iew.
In he u u e we a e in e es ed in con as ing hese ac s wi h o he acous ic indices such as
STIiRASTI and LEF, also using o he so wa e ools.
REFERENCES
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2.
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in Go hic-Mudeja chu ches,”
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Mudeja es,”
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y
Quimica,
Las Palmas de G an Cana ia, Spain, pp.25-26, 1997.
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de Se illa, Se illa , pp. 32, 1983.
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W.,
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6.
Ba on, M., Lee, L. J.,
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