C haptEr 9 design Environments and systems
376
magnetorheological devices (see Sections 8.5 and 9.2). Other kinds
of active damping devices might similarly benefit from the use of
nanomaterials.
sound sources
The world of microphones, speakers, and other devices provides
a rich context for the use of nanomaterials. The design of these
kinds of devices, and the way that materials are used, has already
reached high levels of sophistication and is a topic beyond the
scope of this book. Here we will give only a flavor of activities in
this area.
Considerable attention is being paid to nanomaterials in loudspeaker designs. The basic components of a loudspeaker are
a magnet and a coil attached to a flexible cone or diaphragm.
Passing an electrical signal through the coil causes the cone to
move toward or away from the magnet. The cone causes air near
the speaker to be alternately expressed and expanded, thus creating
sound waves. Nanocomposites are being explored for use in cones
to achieve small variations in diaphragm weight and stiffness that
could positively improve performances. In a moving coil design
for loudspeakers, magnetic fluids are used to provide increased
power capabilities and smoother frequency responses. The fluids
also conduct heat away from the coil and provide dampening
actions to the cone. Nanoparticles can have unique magnetic properties (see Section 7.5) and can be used in magnetic nanofluidics.
These, in turn, could find use in these speaker designs to improve
performances.
Other approaches to using nanomaterials can be quite different and
can address specific design issues. A major company, Panasonic, has
released a product designed specifically for portable devices such as
laptops that are well known for their poor sound quality. The tinny
sound results from conventional small speakers not being able to
produce high-fidelity, low-range sounds. In these small speakers,
the needed movement of the diaphragm is detrimentally affected
by the air pressure developed within the surrounding enclosure
when low-frequency sounds with their large amplitudes are produced. Though the effect is momentary, the increased pressure
within the cabinet affects the vibrating diaphragm and reduces
sound quality. This effect is not present in speakers with large
cabinets.
In some technologies, carbon materials have been placed in small
speaker volumes to attempt to absorb moving air molecules, but
376
magnetorheological devices (see Sections 8.5 and 9.2). Other kinds
of active damping devices might similarly benefit from the use of
nanomaterials.
sound sources
The world of microphones, speakers, and other devices provides
a rich context for the use of nanomaterials. The design of these
kinds of devices, and the way that materials are used, has already
reached high levels of sophistication and is a topic beyond the
scope of this book. Here we will give only a flavor of activities in
this area.
Considerable attention is being paid to nanomaterials in loudspeaker designs. The basic components of a loudspeaker are
a magnet and a coil attached to a flexible cone or diaphragm.
Passing an electrical signal through the coil causes the cone to
move toward or away from the magnet. The cone causes air near
the speaker to be alternately expressed and expanded, thus creating
sound waves. Nanocomposites are being explored for use in cones
to achieve small variations in diaphragm weight and stiffness that
could positively improve performances. In a moving coil design
for loudspeakers, magnetic fluids are used to provide increased
power capabilities and smoother frequency responses. The fluids
also conduct heat away from the coil and provide dampening
actions to the cone. Nanoparticles can have unique magnetic properties (see Section 7.5) and can be used in magnetic nanofluidics.
These, in turn, could find use in these speaker designs to improve
performances.
Other approaches to using nanomaterials can be quite different and
can address specific design issues. A major company, Panasonic, has
released a product designed specifically for portable devices such as
laptops that are well known for their poor sound quality. The tinny
sound results from conventional small speakers not being able to
produce high-fidelity, low-range sounds. In these small speakers,
the needed movement of the diaphragm is detrimentally affected
by the air pressure developed within the surrounding enclosure
when low-frequency sounds with their large amplitudes are produced. Though the effect is momentary, the increased pressure
within the cabinet affects the vibrating diaphragm and reduces
sound quality. This effect is not present in speakers with large
cabinets.
In some technologies, carbon materials have been placed in small
speaker volumes to attempt to absorb moving air molecules, but