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regional theatre (Building C) and community center (Building A) buildings on the northern edge of the complex should diffuse much of the Bernal Avenue traffic noise. The traffic noise from 1-680, although somewhat less in intensity at the Bernal Avenue location, is als0 more broadly scattered, due to the elevated UPRR overpass and transition, making for more difficult attenuation of both direct and ambient sounds at the outer edge of the amphitheatre lawn seating. We recognize the reasons for locating the CAC closer to Bemal Avenue as valid. These include being closer to downtown Pleasanton, and the visual prominence from Bernal Avenue. Our concern with this location has always been tempered by acoustical conditions that we believe to be less favorable than those at the Valley Avenue site. Wherever the amphitheatre is sited, the venue must be quiet within its premises and it must also be a good neighbor, considering that sound generated from the stage must be redirected away from residential areas. With respect to highway noise, the distance from 1-680 might favor the Bernal Avenue site, especially if there is noise attenuation along the freeway. Them will probably be less direct performance noise impacts at the Valley Avenue location. In both cases, we assume similar venue design to further mitigate site noise intrusion by additional berming around the amphitheatm and excavating the lower audience area - both of which am also important for sightline considerations to the stage. If sited at the Bemal Avenue location, performance sound at the amphitheatre may have significant impacts on the adjacent residential neighborhood directly to the west, and could interfere with and be affected by announcements and crowd activities at the sports fields. Noise Implications at the Valley Avenue Location The acoustical diagram (see Attachment 'B') indicates the generation of sound off of 1-680 in a direction that is along the centerline of the amphitheatre. The stage is recessed eight feet below the surrounding finish grades. The sloping terraced seating and lawn bowl rises out of the ground and extends to approximately eight feet above finish grade at the outer cimle of the CAC complex. Assuming that the amphitheatre berm and seating bowl is symmetrical, the pattern of sound off of the highway into the site should be relatively similar. Because the freeway is elevated to the southwest, louder conditions prevail from that direction. The berm and/or vendor structures at the back of the amphitheatre lawn bowl form a solid barrier that results in an acoustical shadow, blocking off-site noise within the seating areas. The attenuation in the amphitheatre should be significant and any "signal to noise" issues (performance sound competing with freeway noise) should be minimal, as performance sound will certainly mask highway noise. The tilt of the fly tower, fo~ing the back of the amphitheatre stage, deflects freeway sound waves passing above the amphitheatre seating, up and away from the audience, thereby keeping reflected sound out of the page 3 M.D, FOTHERINGHAM, LanchcapeArchiteculnc. 323Gea~S~ee~ Suit407 San Franchco, CA 94102 415-4.34-8292