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Acoustic Design:

Rooms and Walls

#1 Siting a building in a

favorable acoustic

environment

Sound transmission in a

free field

#2 Designing indoor

spaces for the proper

acoustic environment

Sound absorption and

reflection

#3 Designing adjacent

spaces for acoustic

independence

Characteristics of sound

transmission in materials

Design Activity Acoustic Issue

Rooms & Reverberant Fields

May have 3 fields

…or fewer…

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Live Spaces• reverberant fields dominate

Dead Spaces• Free field dominates

Dead Spaces Neutral Live Spaces

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Room acoustic goals

Silence—a monarchy

of sound

Lecture halls, auditoria,

churches, theatres

Quiet—a democracy

of sound

Libraries, offices,

restaurants, design

studios, lobbies

None—an anarchy of

sound

Factories, grocery

stores, fast food outlets,

indoor swimming pools

Shape Silence Goal Room to match sound projection

Use reflected sound

to enhance

communication…

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Sound Wave Reflecting Angles• Draw a line perpendicular to reflecting surface

• Incoming angle = reflected angle

Billiards—Acoustics analogy

Orientation and shape affect reflection…

Voxman Hall, UIowa, LMN Architects

Sloped Ceilings can add additional reflected sound for those sitting in the back rows—or not.

Kiel Moe

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Echo Prevention• Sound absorption at back wall and back ceiling• Angle ceiling and walls

This room’s beam enables odd

acoustics by amplifying a phone

conversation 30 feet away while

nearby conversations are

drowned-out by white noise.

SURPRISES

Avoid Focusing Sound

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SURPRISE

Focusing

Dome over elevator lobby at UTexas

produces surprising sound levels.

The Sage

–Foster

Marin County Courthouse, Wright

Isolation--tricky

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Petale, an integrated

sound and light control fixture, designed by

Odile Decq in 2015.

Armstrong Ad a few

months later!

Blue Moon Brewing Co., Denver by Roth Shepard

8’ Diameter Culverts

Surprise Creep

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Japanese American Memorial

Washington, DC

Quiz: creep?

Resonance Chambers• Absorption (Hemholtz)

• Projection (Bandshells)

after Vitruvius

Noise Attenuation Strategies(for sites and rooms)➢ Distance➢ Zoning➢ Absorption & Diffusion➢ Isolation➢ Masking➢ Barriers (math lecture)

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Zoning

Zoning:• Strategic openings

Zoning:• Buffering

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Zoning:

Distance—Barriers

Absorption and Diffusion

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Bateson Building

1970s

products

Custom Shapes

Modern

products

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Before sound

absorption and after(Bonus: light diffusion!)

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Other absorbent

materials…

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Pendleton West

rehearsal hall

Absorbs sound!

Café @ the Building Centre, London

Two absorption strategies!

Diffusion

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Prime Root Diffuser

Design of room absorbers and diffusers can be complex…

Admin Aud photo!

Thamesmead Library Project—Arch 454 Spring 2018

Adam Harfman, Adilyne Nolan, & Deona Swager

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Isolation

Isolation--straightforward

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Masking

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Surprise and Synesthesia• Hearing sound as color

Next time…the math…

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