The document discusses the three fundamental interactions of sound with solid surfaces: reflection, absorption, and transmission. It describes different types of reflective and absorptive surfaces and materials used in architectural acoustics. These include porous and panel absorbers made of materials like open-cell foam that absorb sound energy. Proper use of reflective, absorptive, and diffusive surfaces and materials is important for acoustic design and controlling reverberation in spaces.

1. Submitted By:
Shubham Vasudev, 11627
Sahil Atri, 11645

2. The interaction of sound with solid surface could well be
taken as beginning of architectural acoustics.
Sound waves under goes three type of fundamental
interactions upon interaction with solid surface,
 Reflection,
 Absorption,
 Transmission.

3. 
Reflection is done by two type surfaces:

Finite surface
Infinite surface

(sound absorption coefficient = 0)

4. 
These are the surfaces where when the sound
waves collides it makes the source image on the
opposite side of the surface.

5. These are Surfaces of limited dim. and these surfaces are
used in concert halls, where panels are frequently
suspended as clouds over the orchestra and whole roofing

6. In sound absorption it is the property of the material which
turn The sound energy into other forms of energy – e.g.
thermal energy
Or kinetic energy. (sound absorption coefficient = 1)

7.  Types
of absorbers :

Porous absorbers,

Panel absorbers,

8. 

Air motion induced by sound wave occur between the
particles.
Due to movement through narrow constrictions there
is huge loss of momentum into heat energy.

9. 
Every solid substance absorb sound energy due to its
mass reactance, more is the mass more will be the
sound absorption.
Panel absorbers: in panel
Absorbers partition is done By
only a single panel of sound
Absorbing material.
 Air backed panel absorbers:
In this panel absorbers are
followed by air gap and wall


10. 


Adding sound-absorbing materials to a space
usually becomes an interior design issue .
Absorptive materials are often covered with
acoustically transparent surfaces such as fabric,
perforated metal and spaced wood slats.
These surfaces allow the sound energy to pass
through and be absorbed by the material located
behind.

14. 
Open-cell foam panels are effective sound
absorbers because they have increased surface
area due to the contoured surface of the foam.

15. In sound diffusion sound waves are partially
Absorbed and smaller wavelength waves are reflected. (sound
absorption coefficient = between
0 & 1)

16. 

More the mass of the wall, more is the sound
transmission loss.
increasing the thickness and isolating the sides of
wall, with the help of air cavity between the wall
panels.

17. The STC rating of a wall, floor or ceiling is determined
by the components of the construction and how they are assembled
(Sound Transmission Class)

18. plenum barrier is installed the
operable
wall, extending from the top of
the wall to the structure
underside of the
structure This plenum
barrier is required in order that
the sound insulation value of
the wall is maintained, and not
short-circuited through sound
travelling over the top of the
partition.
Accordion-type operable wall

19. Panel operable walls
provide better sound
insulation than
accordion partitions
because they
are heavier and their
perimeter seals are
more effective
Panel-type operable wall

20. Floor and ceiling assemblies perform two acoustical
functions. Like walls, they provide acoustical separation
between adjacent spaces
 they also
reduce the
sound of
footfalls
and other
impact from
upper floor

Wood framed floor and ceiling

22. Thank you!