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and air-conditioning system elements. Vibrations can be transmitted throughout a whole system. Impact noises, such as something
dropped that hits a surface, also result from vibrations. Mitigation
measures for these sounds can be taken through materials, isolation,
and damping or, as is often the case, some combination. Structureborne sounds emanating from machinery or other vibration sources
can be reduced using low-density materials by disconnecting the
source of the vibration from the carrier and radiating structure.
Passive isolation systems are very common and are accomplished by
breaking the path of vibrations by gaps or the insertion of isolation
devices containing resilient materials that do not transmit vibrations
well. Isolation approaches can be at the device level or at the level
of whole rooms. A direct control strategy would be to provide one
or another type of base isolation devices under the machinery that
damps out or otherwise absorbs vibrations before they are transmitted to the primary supporting structure. A whole host of conventional kinds of these devices already exist and normally use some
kind of resilient material.
Whole rooms can be similarly isolated via the use of techniques
such as floating floors in more sophisticated applications. Impact
sounds can effectively reduced via the use of low-density, light
materials, including resilient materials such as common floor coverings as well as separation or isolation strategies. Impacts on hard,
high-density materials, by contrast, conduct impact sounds quite
well (see Section 4.7).
These approaches are primarily passive in nature. Many types of
active control systems have been developed as well. Costs are invariably high, so most active systems are used in either products or
high-value environments (such as airplane cabins) and rarely in
common building environments. Many use one type or another of
noise cancellation system like those found in noise control headsets. Others use some type of vibrating panel system. For structureborne noises involving vibration transmissions, active damping
approaches have been used, including base isolators in magnetorestrictive materials that change their viscosities when subjected to
varying magnetic field intensities.
space acoustics
In its broadest sense, the term acoustics describes a branch of
science and technologies devoted to the study of sound and related
mechanical waves in various media, including how sound is generated, transmitted, received, perceived, and controlled—and hence
Sound and Acoustical Environments
and air-conditioning system elements. Vibrations can be transmitted throughout a whole system. Impact noises, such as something
dropped that hits a surface, also result from vibrations. Mitigation
measures for these sounds can be taken through materials, isolation,
and damping or, as is often the case, some combination. Structureborne sounds emanating from machinery or other vibration sources
can be reduced using low-density materials by disconnecting the
source of the vibration from the carrier and radiating structure.
Passive isolation systems are very common and are accomplished by
breaking the path of vibrations by gaps or the insertion of isolation
devices containing resilient materials that do not transmit vibrations
well. Isolation approaches can be at the device level or at the level
of whole rooms. A direct control strategy would be to provide one
or another type of base isolation devices under the machinery that
damps out or otherwise absorbs vibrations before they are transmitted to the primary supporting structure. A whole host of conventional kinds of these devices already exist and normally use some
kind of resilient material.
Whole rooms can be similarly isolated via the use of techniques
such as floating floors in more sophisticated applications. Impact
sounds can effectively reduced via the use of low-density, light
materials, including resilient materials such as common floor coverings as well as separation or isolation strategies. Impacts on hard,
high-density materials, by contrast, conduct impact sounds quite
well (see Section 4.7).
These approaches are primarily passive in nature. Many types of
active control systems have been developed as well. Costs are invariably high, so most active systems are used in either products or
high-value environments (such as airplane cabins) and rarely in
common building environments. Many use one type or another of
noise cancellation system like those found in noise control headsets. Others use some type of vibrating panel system. For structureborne noises involving vibration transmissions, active damping
approaches have been used, including base isolators in magnetorestrictive materials that change their viscosities when subjected to
varying magnetic field intensities.
space acoustics
In its broadest sense, the term acoustics describes a branch of
science and technologies devoted to the study of sound and related
mechanical waves in various media, including how sound is generated, transmitted, received, perceived, and controlled—and hence
Sound and Acoustical Environments