Currently,
there are now several ways and means of soundproofing a wall and insulate it.
Improvements in the sound proofing industry have created more products that are
now more effective and less costly than it was before. Sound proof insulation
had come a long way.
Principles
At
this time, though, one needs to understand some of the main principles of sound
movements and how to minimize or totally eliminate it. Some of the principles
include getting the information that the effect of insulation is minimal in
both low and high frequencies.
For a
conventional wall, the effects of insulation are quite similar to having no
insulation. The largest gains are just above the primary low-frequency resonance.
Experiments
Adding
layers to a normal single wood stud well result in the effects of getting the
gains in the mid-range higher at middle and high frequencies. In the low
frequencies, however, the performance is not as good as with the lighter installation.
It is
here where the STC (sound transmission class) ratings rise by a mere 2 points
(from 32 to 34). Insulation has much more value in decoupled walls.
Low resonance points
In
walls having mechanical connections between the two sides, the insulation has
proven to benefits of insulation at middle and high frequencies. In low
frequencies, the capacity of the insulating materials to absorb sound falls
dramatically. The benefits of insulation at low frequencies are to lower the
resonance points.
Lowering
the resonance points is deemed valuable and in walls with damping or
decoupling, the insulation has considerable value at middle and high
frequencies which should be considered mandatory for any sound isolation
application.
Less effective insulation
To
demonstrate how insulation becomes less effective as frequencies fall, place a
fiberglass in front of the mid and high frequency speakers in youth room and
listen to what happens. The sound would probably be muffled or muted.
Afterwards,
put the same fiberglass in front of the subwoofer cones. Nothing happens. This
is the same with the walls.
STC (sound transmission class) ratings
When
dealing with sound, one need to be familiar with STC ratings. STC ratings
measure how much a particular sound proofing construction material reduces
sound. (R-values in thermal insulation are the values of retained heat in the
materials used.)
Higher
STC ratings means the materials used are better at noise reduction. A wall with
an STC rating of 30 will allow most sentences to be heard clearly in a
conversation. A wall having an STC rating of 50 will block most of the loud
speech and only transfer faint sounds of loud musical instruments.
Some guides
Often
enough, people think using denser insulation materials cures every sound
problem. Generally, it is preferable using standard building type insulation.
It is
not advisable to use expensive and very dense insulation. In addition to the
expense, they tend to make low frequency performance worse by raining the
resonance frequencies.
The
use of sound proof insulation is critical and valuable, but insulation alone
cannot win, especially in conventional walls where direct structural
connections exist between the sides.
