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Room Acoustics Special,Issue ROOM ACOUSTICS SPECIAL,ISSUE • Computet Simulation • Neural ,Networks • Sabine Rooms • Office Acoustics Australian Acoustical Society Vol. 23 No.3 December 1995 Yoor PC Here's What it Does: AnyPC-desO.!OPOf pcrt.llIe-c.., be II'lnslllfftled llIlO. K_m ko aly ~ . D 'III'hy$l C SlW (....., ._ Iloo. ......... • TmnsientCaptureandFFT •n" NI'S'lIfI IKJ.". lhrs!:omiwQ 4!I6clllof lJE govftyOlll lo9"l. • Linear andPower Spectrum pOfUble jMt,~m.nt • Synchronous Average • RPM based Spectral Analysis • Runup and Coastdown Waterfalls • Order Tracking • Transfer Function andCoherence + • Realtime Zoom • Correlation Ant-", proteet!'ll • DemodulationandHilbert Transform II ilCAllCsand "",,," 'llM 'll DSP • Stepped SineTransfer Function prOClKloQI'SfofllllM 10000lr>on01 lIlIl • AcousticIntensity ...- ffT ....... • RealtimeV-i Octave Analysis • Shock Response Spectrum • DiskRecord andPlayback • Closed Loop Shaker Control • 1to 16ADCInput Channels One Dynamic Instrument • Multiple DACOutput Channels The DP410FFTAnalvzer ;sfast becomingthe instrument ofchoicefordrnamics solutions. ~lia~fitjj EDITORIALCOMM.,." Neville Fletcher Marion Burgess Vol 23 No3 CONTENTS December 1995 JosephLai ASSISTING EDITOR: ARTICLES LeighKenna BUSINESS MANAGER: Computer Simulation Techniques for Acoustical Design of Rooms MrsLeighWallbank JHRlndel 81 Predicting the Acoustics of Concert Halls Using an Artifical ForAll GeneralBusiness Neural Network (subscriptions, extracopies, back issues,advertising,etc.) F Fricke and C Hoon Haan 87 MrsLeighWallbank Some Notes on Sabine Rooms POBox579 CRONULLANSW2230' DABles 97 Tel (02)5284362 Fax(02)5239637 Notes on Office Acoustics BMurray 105 ForAll EditorialMatters (articles, reports, news, bookreviews, newproducls,etc) TheEditor,AcousticsAustralia Acoustics &Vibration Centre Australian Defence ForceAcademy CANBERRA ACT2600 Tel (06)2688241 Fax(06)2688276 email:[email protected] AcousticsAustraliaispublishedbylhe Diary .... AuslralianAcousticaiSociety (A.C.N.OOO712658) Acoustics Australia Informalion ..... Responsibility lorthecontents ofarticles AustralianAcousticaISocie1ylnformation ... rests upon the authors and not the Australian Acoustical Society. Articles arecopyright,butmaybereproducedin fullprovided adequate reference isquol­ ed.AcousticsAustraliaisabstracledand indexed in Engineering Index, Physics Abstracts, Acoustics Abstracts & Noise: Abstracts,Reviews. Printed by Cronulla Printing CoPtyLtd, 16CronullaPlaza, CRONULLA2230 Tel (02)5235954, COVER: Fax(02)5239637 Reflection of spherical waves from straight edge object- see article by Zhu and McKerrow. ISSN0814-6039 Vol. 23 (1995) No.3 - 77 AUSTRALIAN ACOUSTICAL SOCIETY SUSTAINING MEMBERS ASSDelAnoN Of AUSTRAUAN BRUEL&KJAfRAUSTRALlAPTY LTD NAPSlLEHTfLO AcousnCALCOHSULTANTS PO90Xm. seEllJCKl.At.OST, SCIENCE CENTRE FOUNDATION TfMEYHIUS :z0B,6 Q.AYTON3168 PRlVATEBAG1. CHAOWICKTECH NOlOGY P!A CEENGINEERI'«;P TYLTtI DAALlNGIiJRST2010 9COOK STAEET, 2I2O t.lARlGOlOST F~STVILLE2OEl 7 ASSOClAnOHOf AEVESBY2212 CSR QYPROCK & BRADFORDINSULATION NOISECOfmIOL ENGINEERING ADeLACOMPOSITEPRODUCTS LEVEL5,9 HELP STREET P,O,BOX484 ~NG CHATSWOOD 2067 73-105 FRANKS TOtHIANDE RD. MT.EUZA3930 DANDENONa3175 eMONA1NSTAUMENTS Pt\. BARClAYENGINEERlHG 86PARRAMATTAROAO SAFElYEOUPWENT AUSTRALlA.Pi\. 12·16 CATAlANORO. CAMPEROOWN 2050 35/1-3JUBll EEAVI:. CANNINilVAl..f61S5 ENVlROHMOOALNOISECONlROLP,l WARRIEWOOD 2102 BHPSTEEL, SOAJVERSDERQAO PVRonK PTYLTD SKEETaCOILPRODUCTS DIVISION O!IPPIHGtKlRTON2170 1.7 UAGOWAR 1'10, POBOXn, GP EMBELTOfol&COPTYLTD GIRRAWEEN214.5 t 41-1049BAKERS ROAO PORTKEI.lBLA25OIS WARBURTON FRANKl coeURC33058 BlLSO MAUSTlIAUAPTY lTD OMsion01een·IRH IM dustnes Pf)'Ud INC COAPORATlONPTYlTO 19TEPKO ROAD, 1<10 BUFl'NOODHIGHWAY 22Cl£ElANDROAO TEARYHIu.s2OEl4 BUAlflOOO31 25 OAKLEIGH SCUTH3167 BORALPLASTEABOARD JOYCEAUSTllAUA WOFlKCOVEFlACOUSTICS 616LOOIMERST. -, So9BRIDGERQAO, 132 LONDONDERRY1'1 0 PORTMELBOURNE3207 • MOOREB.l.NK211O LONOONDeARY2753 QuHMln PII10118011 455S r" 10118ol14600 ~fEE3 :9 .....olemAoot"' ... pt,[0315>S1271 ,­ ~ le ee1(r r.. «()3j!65 f956 .... jO.lIY.b1956 _s...... WaIOS /4Cl r.. Pll102I148050l4 Soolll _ . /ffl r.. /02114810 16 lOBI3651ooo r" (Il8j36!>lOOl 78 · Vol. 23 ( 1995) No _3 Acousuca Australla It is now j us t 100 years s ince the from each other and from extraneous did, however, leave also a memorable PrcsidentofHarvardUnivcr1ity dire<:led noises." These criteria cou ld hardly be collection of buildings for which he Wal1acc Clement Sabine, then a young expressed better today, a century later. contributed the acousli c design. The ASlIislanl Professor (i.e. Lect urer) in With only the simplest equipment ­ best known of these is Symphony Hall in physics 10 " propose changes for remember that microphones and valve Boslon,of'C nedin 1890 and still widely remed ying the acoustical difficulties in amplifien had nOIyet been invented- he regarded as one of the world's great the reerore-recm of the Fogg Art wenl on 10 eslablish his famous law for concert halls, &8 well as Ihe first 10 be Museum , I bui lding that had just been reverbera tion lime as a function of desi iJ:nedusingquanlir ative acou slic com pleted" How famil iar those words volume and surfaceab'lOrption, andlater princip les. He laler went on to design sound to the mod ern acous tical went on 10 measure Ihe absorpti on the acoustics of many well known consultan t! ln the course of remedy ing faetOl'1l for many materials and surfaces, buildings, ineluding the Caehedral of St u l lies~ , those " di ffi c Sabine establ ished u well as trans mission losses and many the modem scienc e of archi tectu ral otber properties of practical inte rest John the Divine in I\ ew York, wh ich is acoustics. It is pleas ing 10 record that His papers were published. for the most the largest Golhic cathe dral in the world Harvard recognise d his contribu tion s part , in architectural and tec hni cal The subjeCI has. of course, and later conferred on him an honorary jou rnals rather than in the scientif ic progressed I great deal since Sabin e's Doctcrate of Sclence c he had no PhD· luerarure, so Ihat they would bcavai lable time, but his fundam ental insights still and made him the first Dean of the new to membcn of the profess ion. sland. In this issue, our contrib utors Graduate Schoo l of Appl ied Science. Sab ine 's experimental work Will show how modern techn iques of In his first published paper in 1898, mcticulous, and it was said that he "was mathem atical analy sis and comp uter Sabine wrote: "In order tha t heari ng may reluctant to publish the results of an modelling can give us both an improved be geed in any auditorium, it is cxperiment until he was sure it had been understand ing of lheacouslieproperties necessary that the sound should be done 50 well that nobody would ever of halls and a set of tools not only for suffieiet1tly loud; that the simultan eous need to repeat il." Conseq uently the cs or e~ i s lin g improving the ac o u~ t i halls componern s of a compl ex sound shou ld volume of his publications is not very but , even mor e importantly, for maintain their proper relative intens ities; large. though it includes such innovative opt imizing in advance Ihe performanc e and that lhc success ive sounds in rapidl y lechn iques Ii the vis ualisation of of halls thai are'still in the design stage. moving articulation, either in speec h or aco uslic wavefro nts using spark music, should be clear and distinct, free pholography in small -scale models. He NevjlfeFll'lchl' r COUNCIL OF THE AUSTRALIAN ACOUSTICAL SOCIETY President NProf Charles Don Vice-President Dr Graema Yates Treasu rer Mr Peter Heinze Gene ral Secretary Mr David Watkins Federal Registrar Mr Ray Piesse Cha irman, Sianding Com millee on Membershi p Mr Ken Cook Arch ivist Mr David Watkins Councillors Ne w So uth Wi les Quee nsl l nd South Australia Victor ia We .temAUltral ia Dr Norman Carter Mr Russell Brown Mr Peter He inze A/Prof Charl e s Don MrNorbert Gabriels Dr Stephen Samuels Mr Ross Palmer Mr Byron Martin Mr Claudlo Senese Dr Graeme Yates scoosrcsAustralia Vol 23 (1995) No, 3-79 NO NONSENSE CONTROL OF ENTERTAINMENT NOISE IN FUNCTION & ENTERTAINME NT VENUES ~ ilONT!EC C"lC> Matrix Industries Ply . Ltd. patented wall ties provide structural support while reducing Programmable Noise Monitor transmission of structure borne vibrations (previoosly known as Gax om 2376) Resilient mounting systems are available for all masonry and plasterboard walls and lightweight Simply dial up the Tl;'l uired Sound Threshold f1oatingftoors. • Trigger Range 60 to 120DB Matrix Industries products are reduc ing noise in • Weighting: Linear, A or Low Pass Filter studios and theatres throughout Australia E nq \l ~ ;es and Sakol; Visual Display Unit indicates approaching Thre shold MATRIX INDUSTRIES PTY LTD • Controls ;n lockable Stee1 Cabinet 3 RICHAROSON STREET, TAREE NSW 2430 PH/f AX: (065 ) 522 206 AlsoDisj,jbuled by BRUNSWICK SALES PTY. LTD. 49 LEICESTER STREE T, FITZR OY VIC 306 5 Ph : (03) 9419 0099 Fax (03) 9419 2218 56AThomf"O'lS,_ ~."..,NSW 2047 ~ Dn.", T. ~G18 470 179 Tdif.. , (02) 819 6N8 A(U·Vl8 fledron'cs POIloxW16 A c o u ,I i c g n d V i b r o l i 0 n E I e c l r on i e , W......., h. , NSW 1046 I;or much less th.m anywhere else Calihralion AaJ-VlBEIectronics repa.lr]acillll&J can helpyou with calibration. repair or hire of instrumenls • Sound Level Meters & Filters supplie<l bydiflerent • Noise Dose M eters manufacturers. • Calibrators & Pistonphones \Ve also trade in new and used instruments • N o ise Loggers & Noise Analy ze rs an
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