Pritzker Pavilion Design

Transcription

1 Pritzker Pavilion Design Lecture for: The Concert Hall Research Group Chicago, Illinois - August 2014 Presented by: with Ed Uhlir and Jonathan Laney

2 Presentation Structure Acoustic Goals Behind the Pritzker Pavilion Design based on Indoor Concert Halls How Goals were Accomplished at the Pritzker Perspective of this Talk is 2005 Photo (size may vary) Photo (size may vary) yesterday goals Photo (size may vary)

3 Fundamentals of Acoustics for the Performing Arts Source / Path / Receiver Clarity, Localization, and Loudness = Presence of Sound Running Liveliness and Reverberance Envelopment and Spatial Impression Bandwidth and Noise Timbre Extra Sensory Factors running liveliness presence

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10 Clarity, Running Liveliness, and Reverberance Source is the Performer Listener is, in this case, and Audience Member SOURCE-LISTENER

11 Sound that Contributes to Clarity Direct Sound contributes to clarity First sound which reaches the Listener s ear is directly from the Source DIRECT SOUND

12 Sound that Contributes to Clarity More sound arrives within 50 ms (1/20 th sec) of the Direct sound Reflects off of Walls, Floor, Ceiling, Balcony Faces EARLY SOUND

13 Creating Reverberance Arrives after well after 1/3 rd second Very long sound reflection paths off many surfaces throughout room Reduction of sound level is 20 to 80 or more decibels LATE ARRIVING SOUND

14 short term memory effect lasts 1/3 rd second or longer (Tobias, 1959) Within spaces, our hearing system integrates the sound field heard for apx. 1/3 rd second to form a subjective impression of reverberance

15 From Manfred Schroeder short term memory effect lasts 1/3 rd second or longer (Tobias, 1959) Within spaces, our hearing system integrates the sound field heard for apx. 1/3 rd second to form a subjective impression of reverberance

16 From Room Acoustics by Heinrich Kuttruff short term memory effect lasts 1/3 rd second or longer (Tobias, 1959) Within spaces, our hearing system integrates the sound field heard for apx. 1/3 rd second to form a subjective impression of reverberance

17 By Leo Beranek, Journal of Audio Eng. Soc. 2008

18 By Leo Beranek, Journal of Audio Eng. Soc. 2008

19 5 zone of disturbance with single reflection 0 direct sound -5 image shift coloration -10 clarity level in db bloom running liveliness -25 approximate threshold of single reflection time in ms

20 Backward Inhibition per Georg von Bekesy

21 Perception of sound during the decay process

22 How do reflections stronger than direct occur? Lesser direct sound (directivity/orientation, seat dip) Stronger sound reflection paths due to source directivity Multiple reflections in same time window (20 to 30 msec) Focusing A broadly-spaced arrangement of same instruments playing same part (example: V1 section with 16 violinists) bloom Photo Photo Photo

23 from Sabine Centennial Symposium paper by Talaske and Prince

24 from Sabine Centennial Symposium paper by Talaske and Prince

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26 Acoustic Essentials: Clarity and Reverberance ongoing music

27 Sound that Contributes to Running Liveliness Sound arriving 50 to 300 ms after the Direct Sound Longer reflections off multiple surfaces in room, particularly sidewalls Creates audible reverberance while music is ongoing Running Liveliness

28 Want Vitality? Design for Running Liveliness reverberanc e ongoing music

29 Conclusions regarding running liveliness Sound reflections occurring within the first 1/3 rd of a second strongly influence the perception of reverberance during ongoing music Because of Backward Inhibition, sound reflections in the 200 (100?) to 350 msec range may be(?) the most important for the perception of reverberance Strong sound reflections in this time range create forward masking and can blackout our hearing system from 1/3 rd to 1 second Sound reflections occurring within the first 1/3 rd second are as important at creating the perception reverberance as sound reflections occurring in the 1 to 2+ second range.

30 Pritzker Music Pavilion Chicago, IL

31 Understanding the Musicians Needs A working environment for musicians Acoustic environment must support ease of hearing The tonality of instruments must match the musician s intent The facility must return sound to the stage to give performers the confidence they need. Stage design must address noise concerns for musicians The perception of sound is a highly personal experience. It is neither an art nor science, but our own private view through one of the windows of the senses. Dick Heyser, Scientist Jet Propulsion Labs

32 Acoustics for Indoor Music Halls achieving clarity, loudness, localization, reverberance, envelopment, and proper timbre Shape the architectural envelope and choose the materials to provide: Strong direct sound to listeners Quickly-arriving sound reflections Frontal sound reflections from ceiling surfaces in combination with reflections from sidewalls Sound reflections arriving laterally An abundance of large and heavy surfaces to reflect low pitched sound Control of noise

33 Creating a Concert Hall Experience Outdoors The goal of the Jay Pritzker Pavilion is to create a sound environment similar to the finest indoor concert halls Few wall, floor and ceiling surfaces exist outdoors. The seating capacity is very large at the Jay Pritzker Pavilion The methods for creating an outdoor concert hall experience are different versus indoor concert halls goals realities methods

34 On-Stage Acoustic Environment frontal view of stage Facilitate communication between musicians and aid them in the creation of their beautiful music. The shape of the walls and ceiling offers multiple opportunities for sound to be reflected across the stage, offering performers the cues needed to coordinate their timing, timbre and intonation with their fellow musicians. Ability to focus

35 Music Reinforcement System A carefully designed music reinforcement system provides the clarity and loudness of music so the detail of the music can be heard by the entire audience of 10,000 people. The concentric arrangement of loudspeakers and the use of digital delays create the impression that sound is arriving from the stage, even when most of the sound arrives to distant patrons from nearby loudspeakers. Ability to focus

36 Acoustic Enhancement System side view Patrons are immersed in sound that arrives from all directions, resulting in a three-dimensional sound experience. Laterally-arriving sound also serves to mask the noises of the city, allowing listeners to focus on the music experience. Ability to focus

37 Acoustic Enhancement System frontal view Downward-facing loudspeakers deliver sound that is enhanced by specialized LARES electronics to simulate sound reflections typical of the world s finest indoor concert halls. Sound arrives from all directions, creating a virtual concert hall experience outdoors. Ability to focus

38 Sound Synchronization 0 to 0.1 second

39 Sound Synchronization 0.1 to 0.2 seconds

40 Sound Synchronization 0.2 to 0.4 seconds

41 Sound Synchronization greater than 0.4 seconds

42 Millennium Park Impulse Response with Enhancement and Reinforcement: Summer 2004 Impulse Response: 1ms Averaging

43 Millennium Park Impulse Response with Enhancement and Reinforcement: Summer 2004 Impulse Response: 20ms Averaging

44 Millennium Park Impulse Response with Enhancement and Reinforcement: Summer 2004 Impulse Response 20ms Averaging EDT = 2.35 s -30 db/sec Decay Line

45 Fundamental Physical Acoustics & Communication The floor surface beneath a performer is a key consideration. Floor can be used to facilitate sound reflections. Floor facilitates additional sound radiation. Floor offers a tactile path of communication between musicians. tactile communicatio n

46 Innovation Riser Design

47 Test Set-up and Procedure Test Room Racquetball Court Not without limitation Valid airborne measurements possible down to the 63Hz 1/3 octave band using a sweeping microphone technique within a 4ft x 4ft x 8ft zone. Excitation Source Band limited white noise (31.5Hz-1kHz) delivered through two AURA shakers. At 4lbs each, these are soft sources. Airborne Data Acquisition Time- and space-averaged 30 second samples were captured with a LD۰2900 RTA in 1/3 octave bands.

48 Test Set-up and Procedure 2 Occupants (Load) Two 160lb concrete people on each riser box, in mock chairs. Vibration Data Acquisition Two Wilcoxon Research 793L accelerometers into LD۰2900 (1/3 octave band). Multiple S-R Locations 2 vibration sources 3 measurement locations on each box 1 reference near a driving point.

49 A-B Comparison Velocity Level Difference (db) Average Vibration Level Difference Receiver B - Source A Rigid Iso-Mid Iso-Top Iso-Mid shows little loss at lower frequencies /3 Octave Band Center Frequencies (Hz) Iso-Mid & Rigid very close. Iso-Top much less. What is desirable?

50 A-C Comparison 5.0 Average Vibration Level Difference Receiver C - Source A [Low to High] Iso-Mid shows less erratic behavior. Velocity Level Difference (db) Rigid Iso-Mid Lows transmit best /3 Octave Band Center Frequencies (Hz) Iso-Mid & Rigid similar. What is desirable?

51 C-A Comparison Velocity Level Difference (db) Average Vibration Level Difference Receiver A - Source C [High to Low] Rigid Iso-Mid Transmission is much poorer at low frequencies /3 Octave Band Center Frequencies (Hz) Iso-Mid & Rigid similar. What is desirable?

52 Cello Condition SPL Leq (db re: 20µPa) Time Averaged SPL from Cello Source (Normalized based on accellerometer reference) Rigid Iso-Mid Iso-Top Iso-Mid shows highest radiated levels. Iso-Top shows lowest levels at low frequencies /3 Octave Band Center Frequency (Hz) Cellist subjectively prefers the Rigid or Iso-Mid condition. Vibration transfer results are similar with cello source.

53 Phase 1 Apparent Conclusions Based on our Experiment: Iso-Mid is most effective for vibration transfer. Iso-Top is poorest airborne radiator. Iso-Mid shows airborne radiation performance similar to or in some cases better than Rigid. Vibration transfer from A C is not equal to transfer from C A. Cello source shows Iso-Mid as most effective airborne radiator. What about different floor constructions? With the effective use of resilient materials, vibration transfer between risers can be improved without apparent detriment to airborne radiation from risers.

54 Phase 2 Floor Investigation Airborne Test Only Five Floor Constructions 2x 3/4" Plywood 3/4" Maple T+G on 3/4" Plywood 3/4" Red Oak T+G on 3/4" Plywood 2-1/4" Douglas Fir T+G Decking 3/4" Maple T+G on Honeycomb and Plywood Sandwich Panel *Courtesy of Wenger Corporation Three Configurations Rigid Iso-Mid Rigid Variation

55 Sample Floor Data All Plywood sub-floor conditions show similar radiation behavior. Douglas-Fir deviates from Ply trend somewhat. Honeycomb shows most erratic radiation behavior. What airborne radiation behavior is desirable?

56 Troy Savings Bank Music Hall Troy, New York 1,180 seats Used by Albany Symphony, touring orchestral/solo groups, touring pop/jazz acts Opened 1875 (+organ 1890) Renovated 2005 by TALASKE with Mendel Kleiner

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58 Troy Music Hall Triumphs Proportions are magnificent (dumb luck?) One of the few halls in the US that bears resemblance to the great European masterpieces (of the same era) Former prosperous economy of Troy put the hall on the map Attention from modern acousticians gorgeous sound

59 Troy Music Hall Variable Changes Retractable/removable curtains on rear wall in balconies Panels on upstage wall Panels on semi-ellipse under organ No spectacular RT variation

60 reverberation time t30 (seconds) with vs. without octave band center frequency (hz) variable acoustic 3.0 curtains & panels early decay time (seconds) octave band center frequency (hz)

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62 Right angle corners return sound back to the source. Obtuse and acute angle corners redirect sound to locations within the room other than the source.

63 Pritzker Pavilion Design Lecture for: The Concert Hall Research Group Chicago, Illinois - August 2014 Presented by: with Ed Uhlir and Jonathan Laney