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08 Sound measurements AQM Letter CORPORATE OFFICE 255 Grant St. SE, Suite 600 Decatur, AL 35601 256.351.0121 www.alliancetechnicalgroup.com September 14, 2023 Six Flags Great Escape Theme Park and Lodge Rebecca Wood, President 1172 State Route 9 Queensbury, NY 12804 RE: 2023 Investigative Sound Measurements Six Flags Great Escape Theme Park and Lodge AQM-2023-0021-R2 Dear Ms. Wood, Alliance Technical Group (Alliance) is pleased to provide this report of investigative sound measurements for the Six Flags Great Escape Theme Park and Lodge (Park) in Queensbury, New York. The purpose of the measurements was to quantify sound levels near the Alpine Bobsled (Bobsled) and Comet coaster rides and also qualitatively address potential effects, if any, on overall Park sound from the proposed future replacement of the Bobsled with The Bobcat roller coaster. Measurement methodology, results and conclusion are presented below. Methodology Sound levels were measured with a Type 1 sound level analyzer at four locations around both rides (one measurement set at each of four locations per ride). For both rides, two measurement sets were located adjacent (near-field) to sections of the track where sound levels from the ride were expected to be greatest. These locations were either 1) at the base of a straightway hill midway along the track or 2) on the inside or outside of a curve. The third and fourth measurement sets were located at mid-field distances of approximately 50 yards and 100 yards, respectively, outside and off the end of each the tracks. Measurement locations are presented in Figure 1 and described below: • Bobsled o B-1: ~15 yards west of the inside mid-track o B-2: ~10 yards from and inside the southeast curve o B-3: ~50 yards south of the southeast curve o B-4: ~100 yards north of the north curve • Comet o C-1: North of mid-track; Adjacent to track; ~7 yards from base of 1st drop o C-2: Edge of southeast curve next to fence; an estimated 15 yards from the top curve o C-3: ~50 yards south of southeast curve o C-4: ~100 yards east of southeast curve on Highpointe Dr. circle (offsite) CORPORATE OFFICE 255 Grant St. SE, Suite 600 Decatur, AL 35601 256.351.0121 www.alliancetechnicalgroup.com During each set of measurements (~20 minutes per set, except as noted), A-weighted and octave band sound levels (dBA) were recorded by the sound analyzer at a rate of 32 samples per second and automatically stored as time-averaged data into internal memory, from which the analyzer automatically calculated several overall sound level descriptors for the measurement period. During each measurement period, field notes were made to document typical maximum sound levels as observed from the analyzer’s real-time digital display, as well as sound from any other major noise sources, as applicable. During the measurements, winds were calm or nearly calm, and there was no rain. Field data forms are included in Attachment 1, and copies of analyzer calibration certificates are in Attachment 2. Results Results of the sound measurements are presented in Table 1. The following descriptors for A-weighted sound levels are used to summarize each set of measurements: • L90 – Sound level reached 90% of the period. Characterizes near-continuous background sound. • L01 – Sound level reached 1% of the period. Characterizes near maximum sound. • Lmax – Maximum sound level (slow meter response). • Leq – Energy-average sound level during test period. In addition, Table 1 presents the following: • Maximum octave band sound level in unweighted decibels (dB) from 31.5 to 8000 hertz, and • Notes on typical maximum sound levels of rider pass-by events and/or other prominent Park sounds as observed from the analyzer real-time display or through review of analyzer raw data. Near-field Results. As indicated in Table 1, maximum A-weighted sound levels measured near each ride were within 1 to 2 dBA of each other as follows: • Bobsled (B-1 and B-2): 84 dBA at 15 yards to 90 dBA at 10 yards • Comet (C-1 and C-2): 86 dBA at 15 yards to 91 dBA at 7 yards During these measurements, onsite background sound levels (L90) that include sound from other normal Park operations were in the mid 60’s at the Bobsled and mid 50’s at the Comet, and at that relative level would have had little to no effect on the measured maximum sound levels near the rides. 50-yard Mid-field Results. At the 50-yard distance (B-3 and C-3), non-ride Park sound sources were responsible for the Lmax results recorded by the analyzer at B-3. However, sound levels observed from the analyzer real-time display indicates maximum sound levels within 2 dBA of each other as follows: • Bobsled (B-3) at 50 yards: up to 72 dBA • Comet (C-3) at 50 yards: up to 74 dBA CORPORATE OFFICE 255 Grant St. SE, Suite 600 Decatur, AL 35601 256.351.0121 www.alliancetechnicalgroup.com 100-yard Mid-field Results. At the 100-yard distance (B-4 and C-4), Lmax sound level results recorded by the analyzer for both rides were also due to non-ride sound sources. B-4 was biased from Park trash cart sound, and C-4 was biased high due to nearby vehicle sound and local resident voices. However, observation notes and review of analyzer data showed the following: • Bobsled (B-4) at 100 yards: up to 65 dBA • Comet (C-4) at 100 yards: up to 55 dBA. It should be noted, however, that the Bobsled track was visible at B-4, while the Comet track was not visible at C-4 partially due to an intervening residence which may have reduced Comet sound levels at C-4. It should also be noted the west end of the Comet track was clearly visible at B-4 at a distance of ~50 yards away and was observed to have a maximum sound level of up to 72 dBA during rider pass-by events on the Comet’s west curve. Conclusion Measurements near to and at 50 yards from the Bobsled and Comet indicate maximum sound levels from the two rides are within 2 dBA of each other, which is not a perceptible or noticeable difference in sound level 1 . Therefore, the maximum sound levels from the Comet and Bobsled are deemed similar and comparable. A design comparison of the Comet to The Bobcat, with respect to potential noise-reducing design features was reviewed by the ride’s manufacturer, The Gravity Group, LLC. A summary is presented in Table A. Table A. Comparison of The Comet and The Bobcat Comparison Metric The Comet The Bobcat Comments Structure Material Steel Wood Wood structure will be more sound absorbent than steel structure Maximum Speed 55 mph 40 mph Lower overall speed relates to less noise Passengers/Train 24 12 Fewer passengers results in less noise per train Braking Mechanism Traditional Pinch Brake Magnetic Brakes Non-contact magnetic brakes offers smoother, more quiet braking, Train Type Fixed wheels Steerable wheels Steerable wheels smoothly negotiate turns on track, so less noise Alliance concurs with the manufacturer that the design differences in Table A should offer improved sound control and reduced sound of The Bobcat as compared to the Comet. Alliance, therefore, believes it reasonable to expect that The Bobcat would likely be quieter than the Comet. Further, since sound data reported herein indicates the Bobsled maximum sound level (dBA) similar and comparable to the Comet, Alliance also qualitatively concludes that the Bobcat would be expected to be quieter than the Bobsled. 1 New York State Department of Environmental Conservation Program Policy, Assessing and Mitigating Noise Impacts, February 6 2001; Minnesota Pollution Control Agency, A Guide to Noise Control in Minnesota, March 1999. CORPORATE OFFICE 255 Grant St. SE, Suite 600 Decatur, AL 35601 256.351.0121 www.alliancetechnicalgroup.com We appreciate the opportunity to provide you these acoustical measurement services. If you have any questions regarding this report, please contact me at (315) 506-2699 or at scott.manchester@alliancetg.com. Yours sincerely Alliance Technical Group Scott Manchester Director, Ambient Services Attachments: Table 1 – Sound Level Measurement Results Figure 1 – Sound Measurement Locations Attachment 1 – Field Data Forms Attachment 2 – Calibration Certificates Table 1 Sound Level Measurement Results 4 of 174 of 175 of 185 of 18 A-weighted Sound Levels (dBA) L90 L01 Lmax Leq 80004000200010005002501256331.5 Inside Mid-track West 5158656986919690867284816620:3114:291515 Bobsled: 81-84 Inside Southeast Curve 6174809381929386827290826420:0314:521410 Outside Southeast Curve 5662707674778280667077756620:0714:021450 B-4Outside North Curves 100b 7176797977838781806283725420:0117:1914 Mid-track - Bas C-1e of 1st Drop 7482868990898384827391885520:3915:394 Near track: 90; 1st Drop: 90; 3rd track: 83; Far track: 77 Edge of Southea 7277788185878775766786825520:0516:03415 (top curve)C-2st Curve 1st turn (low curve): 75-78 Top curve: 86 Outside Southea 50C-3st Curve 5663686973717570696274725720:0116:394 Low curve): 63 Top curve: 74 3743495350616361615168664508:4517:49NA100C-4Highpointe Dr. Circle (Offsite) a Approximate distance to tracks with highest decibel (dBA) car passby sound. b Observed from sound analyzer real-time display during test. c Also ~50 yards from west curve of Comet. Notes:Measurements at C-4 were curtailed after 8:45 minutes due to ride end-of-day shutdown Lnn - Sound level occurring nn% of the test period. L90 characterizes near-continuous background sound. L01 characterizes near maximum sound. Lmax - Maximum sound level (slow meter response). Leq - Energy-average sound level during test period. NA - Not available; track not visible. Table 1 Sound Level Measurement Results The Great Escape August 29, 2023 Bobsled Comet Location Description Ride Events Start Time (EDT) Elapsed Time (mm:ss) Ride ID Track Distancea (yards) Maximum (Lmax) Octave Band Sound Levels (dB at each hertz frequency) Bobsled: 68-72; Music: 68-70 Non-ride Park sound: up to 77 Coaster: 55;Park rumble: 47; Non-park (offsite) sound: 68 B-1 B-2 B-3 Observed Maximum Ride or Park Sound Levels (dBA)b Bobsled (Typical): 81-82 Bobsled (w/ loudest riders): 90 Bobsled: 61-65; Comet: 69-72 Non-ride Park sound:74-83 5 o f 1 7 5 of 17 4 (nearest track) 7 (1st drop) 6 of 186 of 18 Figure 1 Sound Measurement Locations 6 of 176 of 177 of 187 of 18 1/1 Figure 1. Sound Measurement Locations – August 29, 2023 - Sound Measurement Location 7 o f 1 7 7 of 178 of 188 of 18 Attachment 1 Field Data Forms 8 of 178 of 179 of 189 of 18 9 o f 1 7 9 of 1710 of 1810 of 18 10 o f 1 7 10 of 1711 of 1811 of 18 11 o f 1 7 11 of 1712 of 1812 of 18 Attachment 2 Calibration Certificates 12 of 1712 of 1713 of 1813 of 18 13 of 1713 of 1714 of 1814 of 18 14 of 1714 of 1715 of 1815 of 18 15 of 1715 of 1716 of 1816 of 18 16 of 1716 of 1717 of 1817 of 18 Last Page of Report 17 of 1717 of 1718 of 1818 of 18