IV. Cabinet Care
Cabinets have varying materials and finishes, including painted wood, perforated
metal and rubber passive radiator and trim parts. They should be treated as you
would any fine component with similar finishes. Dust lightly with a soft cloth; avoiding
abrasives. If necessary, wipe carefully with a cloth slightly dampened with glass
cleaner to remove heavy soil.
V. Room Acoustics, Speaker Placement, Multiple Subwoofers
and Setting Controls
Room Acoustics
If you are critical about low-frequency response, there's quite a bit of useful
experimentation you can do, especially in combination with the crossover, level, and
phase controls of our subwoofers.
Since the earliest days of high fidelity, one of the main challenges for the designers
of speakers, and of their users, has been the generation of the lowest
frequencies—the deep bass. Many of the most notable developments in speaker
design have been made with a view to getting more bass output from smaller boxes.
One consideration is the size of the listening room. The larger the volume of air a
speaker must excite, the more acoustic output you will require from it to achieve the
sound levels you want. In any environment, sounds attenuate as you move farther
away from their source, but in smaller rooms that tends to be offset by reinforcement
from wall reflections. The larger the space is, the farther the sound has to travel both
to reach the reflecting surfaces and then to get to your ears, which means it has to be
louder to begin with.
With traditional full-range speakers, that involves an intricate matching act between
amplifier power, speaker sensitivity, impedance and power handling. But the bulk of
the power goes to reproducing bass, so the use of powered subwoofers and
separate midrange/treble satellites both allows you to be conservative in the amount
of power your main amplifier produces, and ensures a good match between the low-
frequency amplifier and the woofer it is paired with.
After size, the most important aspect of a listening room is its shape. In any room,
sound reflects off the walls, ceiling, and floor. If the distance between two opposite
parallel surfaces is a simple multiple of the wavelength of a particular frequency,
notes of that frequency will bounce back and forth in perfect phase—an effect called
a standing wave or room mode.
At some points in the room, this note will be reinforced substantially; at others it will
cancel out almost entirely. If the prime listening seat is placed at either of these
locations, the note will be a horrible boom or virtually non-existent. The standing
waves are different between floor and ceiling, side walls, and end walls, unless any
of these dimensions are the same. An ideal listening room would have no parallel
surfaces—an unusual situation, to say the least—so that such waves would not
establish themselves. The worst kind of room is a perfect cube.
Almost all rooms are susceptible to some standing waves at low frequencies, but
their effects can be minimized by careful positioning of both the speakers and the
listening seat. Moving either of these even a few inches is sometimes enough to
cure—or create—an intolerable sound. The only way to find out what works best is
by experimentation.
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