User manual

11
C2/C4/C6/C7 Active
Sub-woofer Installation
4.1 Sub-woofer Placement
The subjective performance of any sub-woofer will be fundamentally influenced by
the acoustic character of the room in which it is used, and its position within the
room.Monitor and sub-woofer systems are most often installed in rooms which are
comfortable to sit and talk in, and the typical mixture of carpets, curtains and soft
furnishings help ensure that middle and high frequencies are reasonably well
controlled.There may however be low frequency problems;either too much or too
little bass.To minimise these problems the sub-woofer should be kept away from
corners or walls.Start with it positioned around 1 metre from the side walls and 2
metres from the back. If the balance is bass-light, the sub-woofer can be moved
towards the corner. Use the sub-woofer controls to optimise satellite integration
and for fine tuning rather than to compensate for inappropriate positioning All
rooms vary and it is a good idea to experiment with both listening and speaker
positions until a good compromise is reached. If the sub-woofer is to be placed in
any form of enclosure,adequate side and top clearance for cooling airflow must be
provided. For professional installations the requirements are often very specific.
Please consult with an experienced professional acoustician if necessary.
More information on sub-woofer installation and use can be found later in Section 5.
4.2 Connection
Either two or three cable connections are required for each sub-
woofer: one for mains power and one or two for the audio signal.
The mains cable is specifically supplied to comply with local statutory
safety approvals and alternatives should not be substituted. If you
intend to use your sub-woofer in an alternative territory please
contact ATC for advice. The mains connection must always be
earthed.
The signal cable(s) and plug(s) should be of a good quality and XLR
terminated. Poor cable and plug quality will compromise the
performance of your sub-woofer.The signal input pin configuration is
illustrated in Diagram 1. If two signal connections are made to the
sub-woofer (i.e. a stereo pair) the left and right signals will be
summed by the amplifier so increasing the effective sensitivity by 6dB.
The mono sub-woofer signal from an audio-visual processor may be
connected to either left or right line-level XLR input.
Diagram 1 - input connection pins
Diagram 2 - balanced cable
Diagram 3 - unbalanced cable
Pin 1,ScreenPin 2,Signal (hot)
Two Core Screened Cable
Pin 3,Signal (return)
3 Pin Male XLR
Connector
3 Pin Female XLR
Connector
To Monitor Input
Hot
Return
Screen
To Source Output
1
2
3
1
2
3
Two Core Screened Cable
3 Pin Male XLR
Connector
Phono (RCA)
Connector
To Monitor Input
Hot
Return
Screen
To Source Output
1
2
3
4.3 Signal Cable Options
Balanced cable configuration is the preferred
option, however unbalanced connection is
possible. Diagrams 2 and 3 illustrate the signal
cable connections required for each option.
Balanced (XLR to XLR) connection offers lower
noise and better immunity to “hum” pick-up.
Unbalanced (XLR to Phono or Two Pole Jack)
connection carries risk of hum caused by multiple
signal earths.
Hum problems resulting from unbalanced
connection may be reduced by making ONE of the
following modifications to the signal cable
connections: If the driving preamplifier (or desk) is
“double insulated” (i.e. has no mains earth),
disconnect the signal cable screen at the RCA
Phono plug end.Alternatively, disconnect the signal
cable screen at the XLR end.This second option will
make the source the reference signal earth.