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CoustICs
Your Room
Your room is actually a component and an important part
of your system. This component is a large variable and can
dramatically add to or subtract from a great sonic experience.
All sound is composed of waves. Each frequency has its
own wave size, with the lower, or bass frequencies liter-
ally encompassing from 10 feet to as much as 40 feet. Your
room participates in this wave experience like a swimming
pool with waves reflecting and becoming enhanced depend-
ing on the size and shape of the room and the types of
surfaces in the room.
Remember that your audio system can actually generate
all of the information required to recreate a sonic event
in time, space, and tonal balance. Acoustically, the role of
an ideal room would be to neither delete nor contribute
to that information. However, nearly every room does to
some degree.
Terminology
Standing Waves . Sound coming from a subwoofer bounc-
es around in a room until a pattern emerges—this is called
a standing wave. Typically, this is only a problem with fre-
quencies below 100Hz. When this happens different parts
of your room experience either an excess or a lack of bass.
Some people believe that having a room without parallel
walls will eliminate this effect. The truth is that non-parallel
walls only generate different standing wave patterns than
those that occur in rectangular rooms.
Usually, you can excite most of the standing waves in a
room by putting the subwoofer in a corner. Listening
position determines which standing waves you will expe-
rience. For instance, if you sit in a corner you will hear
most of the standing waves. This can be an overpowering
experience. Sitting next to a wall can also intensify the levels
of the standing waves that are experienced.
Resonant Surfaces and Objects . All of the surfaces and
objects in your room are subject to the frequencies gen-
erated by your system. Much like an instrument, they will
vibrate and "carry on" in syncopation with the music, and
may contribute in a negative way to the sound. Ringing,
boominess, and even brightness can occur simply because
surfaces and objects are "singing along" with your speakers.
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Room Acoustics
Resonant Cavities . Small alcoves or closet type areas in
your room can be chambers that create their own "standing
waves" and can drum their own "one note" sounds.
Solid Footing
After living and experimenting with your subwoofer, you
may want to use ETC (energy transfer coupler) spikes sup-
plied with the subwoofer (see figure 15). With the use
of these spikes, the subwoofer will become more firmly
planted on the floor and, consequently, bass will tighten
and imaging will become more coherent and detailed. It
is best not to implement the spikes, however, until you
are secure in the positioning, as the spikes can damage
the floor if the speaker is moved. The feet that attach to
the bottom of the Grotto i use a common
Spike Installation Instructions:
1 On a soft, padded surface, carefully lay your subwoofer
on its side to gain access to the bottom.
2 Remove existing feet or spikes. Thread new spikes into
holes and screw them in all of the way. If the subwoofer
does not sit level loosen one spike until level is achieved.
3 By hand, tighten the jam nut snugly against the cabinet.
Do not over tighten the nut.
4 Right the speaker.
Caution: Make sure your hands and any cabling are
clear of the spikes. Do not slide subwoofer as spikes
are sharp and can damage your floor or carpet.
5 Adjust to level by rotating spikes. By hand, tighten the
jam nut snugly against the cabinet when you are satis-
fied that subwoofer is level.
Figure 15 . The ETC™ Spike.
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