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Overview
The Qt Room Control (QtRC) can be used to adjust the
sound masking level for an individual room or a space with
2-8 emitters.
This wall mounted volume control unit is
designed to work with any of the Cambridge Sound Manage-
ment sound masking systems. It installs easily in new or
existing construction and fits in most standard electrical
boxes, including open back, low voltage brackets.
Since the QtRC is designed for a room of up to 8 emitters, a
separate zone should be used in larger areas. The QtRC
controlled room can be its own run from the controller or part
of a run to other areas. Several system layout options are
shown on the following pages and, with each layout, a
suggested usage model is described.
When using the QtRC, the controller needs to supply enough
power over the cable run for the emitters and the QtRC(s).
From the control modules, a single cable run can support 60
emitters; however, an added QtRC reduces the number of
emitters that can be supported, because each QtRC "counts"
as an emitter in the total for the run. The cable run can
support up to a combination of 60 emitters and QtRCs. For
example, if there are 30 rooms with 2 emitters in each room, or
a total of 60 devices (2 x 30 emitters), then a single run of
cable could be used. However, if a QtRC is also used in each
room, changing the total to 90 devices (2 x 30 em 30
QtRCs), then 2 cable runs would be required.
Qt Room Control Volume Settings
The QtRC features a six position switch that adjusts the
sound masking volume in approximately 2.5 dB increments.
The volume will increase as the knob is rotated clockwise, with
the maximum level at the 5 position as shown in Figure 5.1.
The minimum level will be achieved at position 0. Alternately,
this position can be set at time of installation to turn off the
sound masking entirely. This option is controlled by a slide
switch on the QtRC assembly. See Figure 5.2. The "OFF"
position is labeled on the circuit board. Slide the switch to
marked "OFF" side to make position 0 turn the sound
masking completely off. Slide the switch to the "Normal"
position to make position 0 the minimum level. This must be
selected before installation into the wall.
We suggest that the QtRC knob be at position 5 (full clock-
wise) when the room's sound level is being calibrated and set
on the controller. This allows the user to use this system as
calibrated or reduce the sound level
down in 2.5 dB steps.
Alternatively the QtRC knob may be at
position 3 when the room's sound level
is set on the controller. This option
allows the user to adjust the sound
level up or down in 2.5 dB steps.
Installing the
Qt Room Control
The QtRC is designed to be installed
in a single gang box or low voltage
bracket.
All power is supplied from the
control module, so only CAT cables in
and out are required. There are also no
requirements for grounding since it is
done over the CAT cables.
Typical Installation Options
Sound masking is best used at a
constant level so it is perceived as
part of the building's environment.
However, there are specific types of
situations, such as in hospital rooms,
offices, and conference rooms, where it
is desirable to be able to adjust the
masking level. In this situation, a cable can be brought to the
room's QtRC and then connected to the emitters in the room,
as discussed below. The QtRC will be able to decrease the
power supplied to the emitters in the room, thus decreasing
the perceived volume. The following sections and diagrams
show the various layout options.
Two Zone System: QtRCs in closed rooms
In the diagram below, Figure 7.1, the control module has two
or more zones.
The cable run from the first zone (the black cable) service the
open area while the second zone's cable (the red cable)
service the 3 closed rooms. The second zone's cable reaches
the first QtRC (blue box) and uses its built-in splitter (connect
to the QtRC's input jack labeled "In"). Next, a new cable
(shown GREEN) connects to emitters in the room from the
"Room" output jack to create a mini control area. Lastly,
another cable (shown RED) is run from the first QtRC's output
jack, labeled "Out," to "In" on the QtRC to the next room.
After installation, each room will have the same maximum
volume while the emitters in each room can be turned down
by each room's QtRC.
The layout below is the optimal layout when using QtRCs.
With the use of a QtRC, each room's occupant may choose
sound masking levels at or below the calibrated level, recom-
mended to be 42 dB for a closed room, if calibration was done
with the QtRC set to max (clockwise). Alternatively, by calibrat-
ing the rooms' sound masking to be correct with the QtRC at
step 3, each room occupant will have the ability to raise or
lower sound masking level.
One Zone System: Providing adjustment in multiple rooms
using QtRCs and cable splitters in the ceiling
The cable from the sound masking controller reaches splitter
#1. One cable from the splitter connects to
QtRC #1
in the first
room, while the other cable continues down the hallway (red).
In the room, a cable is run from the QtRC room jack to the
input port of the first emitter. Then a cable is run from the
output port of the emitter to the input port of the next emitter
(these cables shown in green). ( Figure 9.1 )
The cable that was extended down the hallway reaches a
splitter that is used in the same way. A cable from splitter #2
goes to the next room, connects to
QtRC #2
while another
cable continues down the hallway. A multi-way splitter can be
used as long as the maximum number of devices on a run
doesn't exceed 60 (as shown with splitter #3 connecting to
QtRC #3
and
QtRC #4
).
The layout in Figure 9.1 allows each room's occupant may
choose sound masking levels at or below the calibrated level,
recommended to be 42 dB for a closed room, if calibration
was done with the QtRC set to max (clockwise). Alternatively,
by calibrating the rooms' sound masking to be correct with the
QtRC at step 3, each room occupant will have the ability to
raise or lower sound masking level.
A Single Room: A QtRC from a cable run to an open area
In the diagram shown below, the maximum volume for the
room with an QtRC is the same as the volume of the emitters
in the open area. The power supplied to all of the emitters in
the open area is the same as the power supplied to the QtRC.
The QtRC has the ability to reduce the power supplied to the
emitters within the closed room. Since a closed room typically
requires a lower sound masking level than an open area, with
the use of a QtRC, a closed room can achieve this lower level
by decreasing the maximum level. ( Figure 10.1 )
