2016 Risku Acoustics - WordPress.com€¦ · 16/03/2016 · 2016 Risku Acoustics Descriptive acoustical criteria explained Dry – dead, clarity, intimacy, brilliance… Liveness

2016 Risku Acoustics



Architectural acoustics

Room acoustics Juhani Risku, architect, acoustician 2016

NTNU SW Innovation Labs

Boston Symphony hall, 1900, Architects McKim, Mead and White, acoustician Wallace Clement Sabine


Studio Auditorium Concert hall Church

Room acoustics – meta-architectural approach Material, structure and formgiving in one package


Archaeoacoustics – history and archaeology Aeroacoustics – sound and air movement Acoustic signal processing – electronic signals Architectural acoustics – acoustics of buildings Bioacoustics – hearing, ear, the living nature and human Electroacoustics – recording, manipulation, reproduction Environmental noise – noise control & planning Experiemental acoustics and soundscapes – create Musical acoustics – instruments, perception & production Processes – ensure and manage good acoustics Psychoacoustics – humans respond to sounds Speech – production, processing and perception Structures and materials – engineering with sound Ultrasonics – high frequencies in use, radars Underwater acoustics – submarines, fish, water and marine Vibration and dynamics – mechanical systems vibrating

Fields of acoustics – physics, technology and the human Profession, innovation and creation

…………………………… Norway

…………………….……….…………………………………… Sony

……….……………………………… Art & Creation

……….…………..…………………… Science & Slow tourism

..….……………………… Innovation & Industry

……….…………..…….……………… Vitruvian approach

…………..…………………… NTNU architects


Richard-Wagner Festspielhaus, Bayreuth Architect Gottfried Semper, 1876



Sound Basics


Sound basics – no decimals Doubling sound pressure makes difference

27…30…33…36…39…42…45…48…51…54…57…60…63…66…69...72…75…77…80…83…85…88…91…94…97…100…103…106…109…112…115 dB

60,1 or 66,4 dB … do not exist in measured real life

Doubling and halfing sound pressure = +/- 3 db


Sound and human being Ear, ears, natural sounds, artificial sound, noise

Sou

nd

pre

ssu

re,

inte

nsi

ty (

dB

)

Equal Frequency (Hz)

Equal loudness (phons)

Binaural hearing – space Soundscape in a room Open air sound Ear


Speech – female and male voice sehsehha


Haas effect – 3D sound, binaural hearing (stereo) Direct sound, early reflections and reverberation without echo – first 50 ms

Haas effect – precedence/direction effect, two equal signlas to ears within 35 ms, binaural effect

85

Headphones – the concert hall turns with your head

dB

1

88

96

Traffic noise over communication – the child doesn´t hear


Sound and noise Sound becomes noise – unwanted sound = noise

Sound levels and maximum exposure time

Noise isolating ear muffs Noise cancelling headphones In-ear earplugs Barrier & shelter


Sound basics – sound travel Different ways and channels


Flanking – noise control – weakest factor matters Start always from the source, reasons and magnitude

http://www.acousticalsurfaces.com/soundproofing_tips/html/Noise_Transmission.htm

Sound will find the weakest link(s) – sound passes around

• Ceilings – Above and Through the Ceiling Space • Floors – Through Floor and Floor Joist Space • Through Windows • Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures • Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions,

Continuous Concrete Floors, and Cement Block Walls • Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures • Plumbing Chases – Junctures Between the Walls & Floor Slab Above or at the Exterior Wall Juncture • Around the End of the Partition Through the Adjacent Wall

transmission

http://www.acousticalsurfaces.com/soundproofing_tips/html/Noise_Transmission.htm


Sound in space Direct sound, reflection, absorption, diffusion

reflection absorption diffusion


Bending sound and acoustic layers Row boat, lake, mach drag, wave drag and bulletproof vests

Sound barriers

Mach drag, wave drag Bulletproof vest

Acoustic layers

Warm air

Reflecting cold water

Acoustic sandwich - No background noise - All senses open

Acoustic half-pipe - Cool air



Features of structures and material


Acoustic form-giving – basic setups 1 Forms and their fit to acoustics


Acoustical structures – basics Typical structures

Floating floor

Hanging ceiling

Floating floor

Structure, material and joint details


Weight kg/m2

Ave

rage

so

un

d r

ed

uct

ion

in

dex

(d

B)

Structural basics – light vs. heavy vs. multi-layer Light, double panel and heavy structures

Sound insulation performance of building materials by mass law


Response of different absorbers Porous, panel and cavity absorbers

Porous absorbers

Panel absorbers

Cavity absorbers A

bso

rpti

on

co

effi

cie

nt

Frequency


Absorption Coefficients Material, structure and thickness

.......

050.0

44332211

AaAaAaAa

VTR


Wood panels Warmth with wood

Music hall = rectangular forms and hard materials =


Dynamically adjustable acoustics Multi-purpose spaces, from speech to music to speech

Speech Singing Band and orchestra

Adjusting between speech and music, soft and hard


Acoustic form-giving – basic setups 1 Room in room - Noisebox Studio, Karachaliou & Kostopoulos

http://www.achilleasxydis.com/filter/architecture/Noisebox-Studio





Acoustic form-giving – basic setups 2 Jon Burton's Laundry Rooms studio


Acoustic form-giving – basic setups 3 Room in room



Criteria Music halls


Acoustical Criteria • Liveness or Reverberance • Clarity vs. Fullness • Loudness • Intimacy • Warmth vs. Brilliance • Uniformity and Diffusion • Texture or Smoothness • Envelopment • Balance or Blend • Sense of Ensemble or Performer Satisfaction

Descriptive acoustical criteria Dry – dead, clarity, intimacy, brilliance…

http://www.phy.davidson.edu/FacHome/dmb/py115/RoomAcoustics.html

“blend”: all seats hear all instruments

“ensemble”: musicians can hear themselves





Descriptive acoustical criteria explained Dry – dead, clarity, intimacy, brilliance…

Liveness or Reverberance: Characterized by the reverberation time of primarily the high and medium frequency ranges. Determined by volume of room and effective surface area. Can be altered by changing area and nature of absorbing materials. Suitability depends on nature of sound or music. A room with too short a reverb time for a particular type of music may classified as "dry" or "dead" while one that is too alive or has too long a reverb time may be called "muddy" or "watery".

Clarity vs. Fullness: Measure of intensity of the direct sound relative to the reverberant or reflected sound. The greater the reflected intensity, the more "full" the room is perceived and the less clear the spoken word or fast or highly articulated sections of music are perceived. Clarity is sacrificed in a "muddy" room but a lesser degree of clarity enhances slow passages of music from the romantic era. To achieve greater clarity or "definition" the entire audience should be close to the stage and have an unobstructed view. This can be accomplished by placing performers on a raised stage and perhaps a raked stage, and by placing the audience on a sloped floor or in balconies.

Loudness: A longer reverb time contributes to the "loudness" of the hall since loudness is a measure of the average power detected by a listener. The relative intensities of ambient and external noise levels are also a factor and should be minimized.

Intimacy: Connected to clarity. The time between the arrival of the direct sound and the first reflection determines the listener's perceived proximity to the performers. An intimate feeling occurs when the initial time delay is between 8 and 20 ms. The more popular halls have a smaller seating capacity because they are generally louder and more intimate.

Warmth vs. Brilliance: This character is determined by the reverb time of the low frequencies relative to the medium and high frequency ranges. In general, the reverb time is a little longer for frequencies below 500Hz than those above. For a nearly constant reverb time as a function of frequency, the room may be classified as "bright" or "brilliant". The longer the lower frequency reverb time is the warmer the room. Yet too long and the room sounds muddy. Most highly regarded concert halls are classified as warm.

Uniformity and Diffusion: Uniform spatial distribution of both direct and reflected sounds throughout the audience. Uniformity in the direct sound can be achieved by minimizing the distance between first and last rows, e.g., a shallow hall with several balconies. Hot spots, caused by the focusing effect of curved walls or domed ceilings, reduce uniformity as well as do dead spots or "shadows" caused by physical obstructions or balcony openings. Objects that diffuse sounds of all wavelengths are necessary for good uniformity.

Texture or Smoothness: For a smooth room there should be no more than 20-30 ms between successive reflections reaching a point in the audience and the intensity of the reflections should smoothly die away in time. Loud echoes can be avoided by not using large flat highly reflecting surfaces and by using sound diffusers of different sizes.

Envelopment: Early reflections, those arriving in the first 100 ms, should arrive from all directions in order to give the listener a sense of envelopment. Recent designs have given more attention to the importance of lateral reflections. Organ music requires an extreme sense of envelopment. Pipes may be placed above, behind, or to the side of the audience to mask the origin of the sound source. For other types of music, too much envelopment can blur the aural image of the stage.

Balance or Blend: Sound coming from different locations on the stage should have balanced intensities. Somewhat related to uniformity. This is generally a problem for seats close to a wide stage. This situation can be balanced with a low, irregularly shaped ceiling and appropriate onstage reflecting surfaces.

Sense of Ensemble or Performer Satisfaction: The performers must be able to hear themselves and the other performers. There should be many reflections strong enough to be heard by the performers but the reflections should decay uniformly and in a time shorter than the shortest time between notes. Flutter echoes reflecting from parallel side walls must be avoided. Acoustic shells increase the sense of ensemble and helps to project more of the sound toward the audience. Ensembles in which members are separated by more than approximately 5 meters easily lose synchronicity and need a conductor to give visual cues.




Reverberation time Time taken for a sound to decay by 60 dB from its original level

Studios Auditoriums Concert halls Churches

direct sound

reflected sounds

http://www.mcsquared.com/problems.htm http://www.mcsquared.com/reverb.htm http://www.mcsquared.com/music.htm

http://abmp3.me/xqnpjrhw/reverberation-reverberation-mp3-download.html

0,2…0,4 s 0,5…1,0 s 1,5…2,5 s 1,2…1,5 s 3…5…8 s

http://www.mcsquared.com/reverb.htm



http://www.mcsquared.com/music.htm









Reverberation time comparison – concert halls Measured reverberation times of best European concert halls; Lorenz-Kierakiewitz,Vercammen


Early reflections – sound field formation Direct sound, early reflections and reverberation without echo – first 50 ms (1/20)


Reflection from room surfaces Straight, corner, convex, concave


Sound travel – basics Direct sound and reflections



best ones... Music halls

Some of the


Musikvereinsaal, Wien, 1870 Boston Philharmony, 1900

Best music halls 1 Musikvereinsaal vs. Boston Philharmony

2631 seats T500-1000 = 1.8 s

2158 seats T500-1000 = 2.05 s


Staatsoper, Wien 1869 (1955) 1658 seats

T500-1000 = 1.3 s

Best opera houses Teatro Alla Scala vs. Staatsoper

Teatro Alla Scala, Milano 1778 2289 seats

T500-1000 = 1.2 s


Philharmonic Hall, Liverpool 1939 Concert Hall, Turku 1952

Best music halls 2 Liverpool Philharmonic Hall vs. Turku Concert Hall

1002 seats T500-1000 = 1.6 s

1955 seats T500-1000 = 1.5 s


Cultural House, Helsinki 1955 Radiohuset, Copenhagen 1945

Best music halls 3 Aalto’s Cultural House vs. Lauritzen’s Radiohuset

1093 seats T500-1000 = 1.5 s

1500 seats T500-1000 = 1.05 s


Chamber Music Hall, densifying sound field Concept created at IRCAM studios 1990, proposal to Besançon, France 2013

Juhani Risku, architect SAFA, acoustician


Over the audience and over the stage, ceiling clouds and panels produce balanced and

blended sounds for a variety of venues, resulting in a rich, directed sound that the

discriminating audiences have come to expect.

Acoustical ceiling panels – problem solving Lack of reflections from the ceiling



DIY people... ... or professional architects?


Structural basics – DIY people Do-It-Yourself and construction physics in conflict


Structural basics – DIY people can do Do-It-Yourself and construction physics in harmony

High frequences - Carpets, drapes, gobelins, curtains - Max. at ¼-wavelength distances

Low frequences - Bass traps (studios) - Fixed furniture - Max. at ¼-wavelength distances

Balance between absorbants by frequency

Combinations - Bookshelves, boxes, drawers - Sofas, armchairs - Garderobe

Absorption only

Medium frequences - Panel structures (walls, floor, ceiling) - Furniture - Asymmetric placement


Forget about…

… Aalto and Rietveld…

… and egg cartons…


Acoustic design – the architect Architectural and conceptual planning & design in detail

Sketching Concepting Design Build Architectural solution Planning Details On-site crafting

Gantt

Decisions of architectural quality – the power of a pencil

Decisions of material investements – the power resourcing

Uncertainty of quality – the power the unknown


Professional inability Architects don’t care or can’t do

Forms which does not fit to acoustics - Form-giving, function - Quality

Details – wrong use of material and its location Education – lack of architectonic fundamentals Consultant effect – outsiders are involved - acoustic engineers dictate - communication fails - architect a bad customer

Target setting – multipurpose vs. quality

Acoustical design problems Function, need and quality – Architects don´t care

Functionional conflicts Acoustics does not meet needs

Extreme values of reverberation time Echoes Room resonances Focusing of sound or hot spots Balcony and column shadows Bad handicraft and detailing External noise Precedence effect – priority conflicts


Exam: For what do you need lights in a music hall ?

– For notes, and notes only. Thank you.





https://www.youtube.com/watch?v=GkNJvZINSEY Science - Transmission of Sound

http://www.acoustic-glossary.co.uk/definitions-a.htm Acoustic glossary

http://piisami.net/tieto/akustiikka.htm Akustiikan perusteita

https://www.youtube.com/watch?v=qgdqp-oPb1Q Erar, hearing

https://www.youtube.com/watch?v=JPYt10zrclQ How Sound Works (In Rooms)

http://www.armstrong.com/reverb/main.jsp Reverberation time, examples

http://threedb.com/rt.php?lang=en http://www.bobgolds.com/RT60/rt60.htm Rough, but best for now: http://www.amfgrafenau.de/index.php?l=2&mode=shownews&artid=534&groupid=155&subcatid=361&maincatid=155& - http://trikustik.at/rak-rechner/ - http://www.acoustic.ua/forms/Reverberation-RT60.html

Reverberation time, calculation

https://www.youtube.com/watch?v=GkNJvZINSEY

http://www.acoustic-glossary.co.uk/definitions-a.htm





http://piisami.net/tieto/akustiikka.htm

https://www.youtube.com/watch?v=qgdqp-oPb1Q



https://www.youtube.com/watch?v=JPYt10zrclQ

http://www.armstrong.com/reverb/main.jsp

http://threedb.com/rt.php?lang=en

http://www.bobgolds.com/RT60/rt60.htm

http://www.amfgrafenau.de/index.php?l=2&mode=shownews&artid=534&groupid=155&subcatid=361&maincatid=155&

http://www.amfgrafenau.de/index.php?l=2&mode=shownews&artid=534&groupid=155&subcatid=361&maincatid=155&

http://trikustik.at/rak-rechner/



http://www.acoustic.ua/forms/Reverberation-RT60.html




Architectural process – Agile and lean waterfall The architect should be planning and designing from the beginning to the finalisation

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2016 Risku Acoustics - WordPress.com€¦ · 16/03/2016 · 2016 Risku Acoustics Descriptive acoustical criteria explained Dry – dead, clarity, intimacy, brilliance… Liveness