The URL can be used to link to this page

Home My WebLink About0130.091~. • • ~ " . :. '.\.- January 24, 1991 Honorable ~ity council Palo Alto, California STQJ)J BE COJVItJlr.ITY MOISE IMPACT Of S~ AMPBITHf~ CONCERTS Me.JIll)ers of the. council: This is an informational report and no COuncil action is requested. The city of Palo Alto has remained in contact with the City Manaqer' 5 Office in Mountain View reqardinq sound studies conducted in connection with Shoreline Park Amphitheater. staff has recently received a copy of the consultant report, -Measurements and Mitigation Xethods -Community Noise I~pact of Concert Operations at the Shoreline Amphitheater-by smith, Fausa and MCDonald, Inc. The ExeC"..ltlve. Summary of that report is attached for your information, and the complete report is available in the city Manager's Office. COnnie Martinez, Assistant to the Mountain View City Manager, is the contact person for this issue~ )Is. Martinez has infol'!l.ed staff that the Mountain View City council directed amphitheater staff to work with the performers to voluntarily reduce sound below 98 db on occasions when the inversion is present. This weekJ Mountain View staff will be mailinq the study information to the Palo Alto City Council and each Palo Alto resident who has complained about the noise. Also, Mountain View staff has indicated willingness to liIeet with Palo Alto staff to discuss the report. Staff will continue to coordinate activities regarding the amphitheater noise and monitor progress on that issuea Re;pectfully sab~itted, ... jzi ~~~:J A~stant City Ma~er Attachlllent CMR.130.91 -, - o o EXliCUTIVE SUMMARY The purpose 01 this report is 10 provfde the City 01 Mountain V_ with a summary 01 finO"",s rogarding the cau."," 01 concert sound impacts which have been occurring in neighborhoods up 10 four m,es WW3'J from the Shoreijne Amphitheatre !aolity in Moc.r.tain V_ and 10 present a lsi 01 potential solutions 10 lTL~e these SO<..-1d impacts. MEASUREMENTS AND METHOOOLOGY The acoustical engineering firm 01 Smith. Fause & McDonald, he., (SFMQ was retair>ed by !he City 01 Mountain VIeW during the 1990 Sherer"", Amphitheatre concert season • oonduct !ield sound measurements 01 !he sound irnpac1s oc:curring in neighbort.oods, • determine 1he cause(s) 01 these concert sound impacts, and • develop a list 01 potential solutions 10 mitigale the sound impact A complete descripIion 01 the data and methodology 1JSed by SFM! to produce this report -os provided in Appendix A cI the report. AN DINGS Upon review 01 historical and recent1y coIIec!ed data from sources indu<flf'lg • puOrlC weather data, • concert sound c:omp!aint maps prepared by City 01 Mountain Voew staff, • sound level rroeasurements (Strip chart sound level recordings) taken by the Sherer • .,., Amphitheatre sl¢f, and • data coIIec:ted by SFMI during their synchronous recorclng during several concerts during the 1990 concert season. the report presents !he fDi10wing findings regarding concert sound impacts and complaints • peak concert sound romplaint activiIy does no! ciirectly relate 10 peak sound levels within the Amphitheatre. Some 01 the Ioudesl concerts have produced no complaints, • !he oca.nence 01 complaints appears 10 be highly seasonal. Peak complaints are Shorefrne C<lmmunity Noise 1mpact SFMI Project 670301.3 Measurement & M"digation Methods ; , • , , ,-... - o c:oncemrated In ~ and August, when t"mperature inIIersions are strongest. , !he majority of the sound complaints occur when !he bottom of an inIIersion is reported to be within 500 10.1,000 f<>et of the ground, , sound levels within the Amp/litheatre do no! necessan1y rise significantly across IMe time period from the final intermission 10 the end of tI'.e show, even though the majo<;ty of oomp!aiots come dumg this period, , r a strong 'sound chame!" !-.as been establIShed as the resuft of an ",version, the level of sound impacts In !he neigI1borhoods can be direetJy controlled by so.;oo levels within !he A,np"1itheatre, , the use of contempo!'ary subwoofers Oow frequency speakers) is not tl'ie sole source of sound impacIs In neighborhoods, , low and very low frequency sound impact is the dominant impact of the Amphitheatre. /4..~ e feSUit, ft:'i.abfe assessment using conventional noise ordinance limits is not possible, and • only significant reduction of the sound !eve!s leaving the Amphitheatre would be likely to substantially reduce comp!aints. Ever, highly effective solutions may no! be sufficient 10 BIlminate complaints due 10 residual low frequency sound levels. POTENTIAL SOLUTIONS The report identifies and evaluates arch~ectural and operational solutions as pctentia! methods to rMigate sound impacts i1 the neighborhoods located to the north of the faeiiiIy. . Architectural Solutions , k1staIIation of a high barrier waIT at the back of the facmty. • nstaftation of a permanent 'cage' to restrict the i1staITed location of the touring sound speakers. , hstaIIation of a "Dying canopy" to catch sound as I heads up through the tent arms. • ntaJation of a permanent '!rani of house' (main) sound system, Other potential architectural soI"JIions which were identified In the report, but are considered impractical lor actual implementation lncIucIe Shoreline Community Noise ImpacI SFMJ Project 870301.3 2 Measurement & Mitiga~on Methods • . . o • i16IaIIation of a system of permanent up-dra!t fans to disperse the rwersioo layer, • roIalion of the entire Amphitheatre to direct concert sound toward the San Francisco Bay, and • encIo&ute of the Amphitheatre. Operalio1la1 Solutions • Limit SOU!1d levels at the back wall of the facility • Continue to improve weather and or sound propagation monitoring, i1 effort to predict impacts. • Schedule July and August events during the day time, or discontinue events during these inversion prooe months. Tr.e report does not specifically address mitigation of sound impacts to the South (principally 0CCUfTing i1 a nearby mobile home complex), owing to very limited data and the distinctly differenl nature of solutioos that may be required. RECOMMENDED ACTION The report recommends further investigation of permanent physical, arch~ecturar solutions, rather than op6f8IionaI ones, given lI1e poor !rad< record 01 the latter at sim,ar Iacilities and at the Shoreline facility. As physical solutions may prove prohibitively eKpenSive, however, \he repoo1 recommends that the next step fOr the City of Mountain Voew 10 be a cost assessment of the potential solutions most favored by the City Council by parties quar.'lied 10 do so. The report also recommends that given the refl8nCe cI. bot" this report and \he City 00 Ihe soundleve! data measured 00 sound mon.~Ofing equipment owned and operated by the Amp/'.itheatre, that the mon~Ofing equipment be factory caJlbrated each year. ShofefIll8 Community Noise mpact SFMI Project 870301.3 3 Measuremenl & M"fIigatioo Methods . '