A best acoustical treatment can
be given to an auditorium by applying following consideration
1. If the
auditorium is to be used as a sound film theater or for public address system,
the line of reverberation selected should be short for best acoustic but if the
line of reverberation selected for concert halls and churches should be longer
for best acoustic.
2. The
problem of echoes in auditorium is particularly common when the reflecting
surface is curved in shape. As best acoustical treatment is concerned, this echoes
can be avoided by providing highly absorbent material or grills on the face of
the walls.
3. For a
best sound, necessary in an auditorium, the absorbent material such as porous
absorbents, Resonant absorbents, cavity resonators is used.
4. The
time of reverberation should work out to a value of 3 to 2 seconds of 2 to ½
seconds for a best acoustic.
5. The
shape of the auditorium is the governing factor in avoiding the defects like
echoes or other types of reflections of sound waves. For best acoustic,
Rectangular, fan, horse shoe, circular or oral are the typical possible shapes
of the floor plan of an auditorium.
6. The
walls of the hall are so shaped and placed as to minimize the possibilities of
echoes. Plain walls are found suitable. For best acoustic the convex shaped
walls are constructed to reduce echoes to a greater extent.
7. For
good acoustic with a view to ensure optimum absorption from the audience, the
seats in the auditorium are raked so that heads in one row do not intercept the
passage of direct sound to the persons in the row immediately behind.
A typical raking arrangement of the seats in auditorium
Sound insulation
Control of noise transmission
is essentially to minimize the disturbing effect of sound passing from one room
to another through walls, partitions and floors or ceilings. This noise
transmission from one unit to another can be controlled by sound insulation.
The sound insulation rating of a wall is generally governed by the net sound
transmission loss it provides and also the efficiency with which it serves as a
barrier for speed sound. Weight of the wall is the governing factor in wall
insulation. It is seen that a solid one thick wall plastered on both sides,
proves quite effective as a sound insulating partition wall. It has an average
reduction of 50 dβ Precaution which should be taken to achieve a
better sound insulation in case of college building situated near the road are
as follows:
1. A
cavity wall type of construction should be preferred for college building and
to have insulation increased value, the cavity walls are filled with some
resilient materials.
2. A
number of windows should not be situated to the face side of the road so as to
minimize the sound governed by traffic.
3. Partition
walls made by brick should be thick and well plastered on both sides.
