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Adjusting HSS
Adjust the mounting angle to ensure that
the directed audio is focused at the
correct area of interest.
DIRECT MODE:
As explained earlier in this manual, Direct Mode
assumes that the listener will be in a direct path
in front of the HSS device. He or she will hear
the audible sound as the sound column passes
by their head. The sound will continue to travel
past them until it either strikes a surface or is
absorbed by the air (over a long distance).
What happens to the sound after it strikes
a surface? (Sorry, some basic acoustical
education is coming up…)
A number of things can happen when a sound
wave strikes a surface depending on the
surface itself. If the surface is flat and hard
(e.g. a mirror or plaster board), the sound will
reflect from the surface. Some energy will be
lost, but some of the sound will be reflected
back into the environment. The angle at which
the sound strikes the surface will equal the
angle at which it will reflect (assuming a
perfect reflector). Of course, there is no
perfect reflector so some amount of the
sound will scatter back into the entire area,
while the loudest portion will follow the
refection path.
If the surface is absorptive at the proper
frequencies, the surface will contain the sound
within the surface and little sound will be
directed back into the environment. The last
alternative is to make the surface diffusive. If
you diffuse the reflection you essentially
reflect it back into the room in all directions.
Therefore, no single reflection is louder than
all the rest.
One of the great benefits of HSS is the fact
that we can now predict where the sound
will strike a surface (first reflection) and treat
that surface accordingly. Since traditional
loudspeakers emit sound in all directions, the
sound always sounds like it is coming the
speaker device because no matter where
you are in the room, the first sound you hear
is actually coming directly at you from the
speaker. Now, with HSS, we only have the
one column of sound to deal with.
When you consider the “First Reflection” of
the HSS sound column, remember, you can:
1) REFLECT IT! Angle the HSS device
correctly so that the first reflection is directed
where you want it to go. For example, if you
don’t want to hear the first reflection, direct it
up into the ceiling, or direct it into a absorbtive
surface someplace else in the room, etc.
Also remember that sound does dissipate over
distance. Therefore, the farther you can make
the reflection travel, the lower it will be in vol-
ume when you hear it again. A good example
would be an overhead HSS unit directed down
towards the floor with the first reflection going
back up into the ceiling. If the ceiling were 50
ft. away, the reflected sound would have to
travel 50 ft. up and 50 ft. back down before
you would hear it again. It may be completely
inaudible by that time depending on how loud it
was when it started, the composition of the
ceiling, and ambient sound level.
2) ABSORB IT! Make the surface struck by
the first sound reflection highly absorptive.
The better the absorber, the lower the reflected
energy. Carpet, for example, is a very poor
absorber. It will absorb some of the highest
sound frequencies, but will reflect the remainder.
Some office wall panels are somewhat better,
but still they will reflect the majority of the
energy. A local acoustical technician can
provide you with the most appropriate absorption
material for the individual installation.
3) DIFFUSE IT! Make the surface multi-layered
and multi-dimensional. The more irregular the
surface, the better the diffusion.
NOTE: You can obtain more information
about Reflectors, Absorbers, and Diffusors
from RPG Diffusor Systems, Inc.
http://www.rpginc.com/
Ventilation Requirements
You must insure that the HSS unit receives appropriate ventilation. Do not mount near curtains
or other surfaces that might cover or partially block the ventilation of the unit. If the HSS unit
is ceiling or plenum mounted, ensure that proper ventilation requirements are observed.
Be sure that insulation or other materials do not interfere with the unit ventilation.
Electrical Power Requirements
Refer to the Specifications section at the end of the manual to determine the specific amount of
AC power required for this device. This HSS unit contains highly sophisticated digital circuitry
which can be damaged by noisy AC power or extreme degrees of voltage fluctuation. Use care
to provide properly filtered and controlled AC power to the HSS unit. Use care to provide the
same type of power you would use for a computer or TV.
Audio Connection
AUDIO INPUT: The analog audio input connector is
a 3.5mm female STEREO (tip, ring, sleeve) mini
jack, containing two input channels. In the normal
configuration, the input jack accepts a stereo signal
and sums the two channels together. (for example,
the Left and Right outputs of a standard portable
CD player will be summed together at the input to
the HSS unit).
With the volume control setting on the HSS unit set to FULL Volume, a 0.5V p-p input signal
per channel is the threshold of clipping. You may input a signal up to 2.0V p-p into each channel
without clipping if the volume control is turned down by -12dB or more. An input signal higher
than 2.0V p-p into either channel will clip the A/D converter and turning down the volume control
will not eliminate the resulting distortion. The nominal input level is approximately 1.0V p-p per
channel. This level provides the user the ability to maintain a reasonable level control over the
incoming audio material.
ALTERNATE ANALOG AUDIO INPUT CONFIGURATIONS
Two alternate input configurations are supported without any modifications to the HSS unit:
1) A mono signal may be input into either channel leaving the other channel open or unconnected.
As in the typical stereo case, a 0.5V p-p input yields full output at the maximum volume setting.
2) A mono signal may be input into the HSS unit using a 3.5mm mono male plug. In this case the
input levels are doubled: In other words, a 1.0V p-p input is required to achieve a full output and
4.0 Vp-p is the maximum input before clipping.
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