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ROSEN <br /> GOLDBERG <br /> DER & <br /> LEWITZ, INc. <br /> 1100 Larkspur Landing Circle 4375 Larkspur CA 94939 - Tel 415 464 0150 • Fax 415 464 0155 - RCOLacoustics.com <br /> MEMORANDUM <br /> Date: <br /> 1 November 2012 <br /> To: <br /> Company: <br /> Brian Dolan, Director of Community Development City of Pleasanton <br /> From: <br /> Alan Rosen <br /> Project-Subject: RGDM.Job number: <br /> Downtown Hospitality Guidelines- Noise Levels and Groundbome 11-089-2 <br /> Vibration <br /> This memo presents answers to city staffs questions has regarding sound <br /> propagation and groundbome vibration. <br /> Question 1: For a venue in the transition zone, what is the level at the residential <br /> area (about 60 feet away) if the noise level from non- amplified music is <br /> 70 dBA at the property line? <br /> Answer 1: The noise level at the residences would be about 60 dBA (59.4 dBA <br /> calculated). <br /> Question 2: For a venue in the core area,what is the level at the residential area <br /> (about 92 feet away) if the noise level from an amplified event is 74 dBA <br /> at the property line? <br /> Answer 2: The sound level at the residences would be about 81 dBA 1080.6 dBA <br /> calculated). <br /> The sound level at the residences will depend on the location of the noise source with <br /> respect to the property line. In the examples above, it was presumed that the source <br /> was about 25 feet from the property line. <br /> Music is conveyed to listeners through very small fluctuations in air pressure. These <br /> fluctuations are perceived by the human hearing mechanism as sound. These small <br /> pressure fluctuations lack adequate energy to cause feelable groundbome vibration. <br /> Groundbome vibration is more commonly caused by heavy vehicles on roadways or <br /> tracks (trucks and trains) or large machinery such as pile drivers or compactors. <br />