User manual

2.1 Centre Speaker
Placement
The positioning constraints on a centre channel
loudspeaker are always influenced by the type and
location and of the associated screen.However, the
basic parameters that influence the subjective
performance of any loudspeaker in a listening room
- alignment to the listening position and proximity of
room boundaries - also apply to a centre channel
and should be taken into account.
The C1 and C3 are intended to be positioned
relatively clear of room boundaries and centrally
either just below or just above the screen. If the
screen is either a plasma or projector type located
close to the wall it may not be possible to position
the C1 or C3 very far forward.In these cases,some
adjustment of low frequency equalisation via the AV
processor may be necessary to reduce excess bass.
It is always preferable however to experiment with
loudspeaker positioning before resorting to
electronic equalisation.
If the screen is a CRT type and its stand is also to
carry the C1 or C3 it is advisable to mount the
speaker via some decoupling material so that
vibration does not disturb the picture.
While every ATC centre channel speaker is
effectively magnetically shielded, the extreme
sensitivity of some CRT tubes to residual levels of
magnetic flux may mean that, in rare cases, ATC
centre channel speakers are not appropriate.
Adjusting the relative front/back position of the
center speaker and the CRT can reduce magnetic
interference but should your screen suffer
intractable picture distortion caused by the
proximity of a centre speaker contact your dealer
or installer for advice.
More information on loudspeaker positioning in
multi-channel systems can be found later in this
manual in Section 5.
2.2 Amplification
The choice of partnering amplifier for the C1 and C3 will have significant influence on
the performance of the system.Consider the following when selecting the amplifier:
• With any passive loudspeaker there is a trade-off between low frequency
extension and sensitivity. The C1 and C3’s extended low frequency response
means that their sensitivity is relatively low. It is advisable therefore to select an
amplifier of relatively high power capabilities. Use of an under specified amplifier
will result in distortion at high levels and may risk damage. Valve or solid state
amplifiers with high output impedance should be auditioned carefully to establish
that their characteristic reduced damping at low frequencies is acceptable.
• Thanks in part to their underhung voice coil construction,the C1 and C3 not only
demonstrate extremely low distortion at all levels but also a greatly enhanced
effective dynamic range.This exceptional distortion performance, also combined
with very wide dispersion,will ruthlessly reveal deficiencies in ancillary equipment.
It is advisable therefore to audition the C1 or C3 with your proposed amplifier
and ancillary system.
2.3 Connection
The C1 and C3 are equipped with a “bi-wire” connection panel that enables
separate amplification of the bass drivers and tweeter. Remove the linking bars
between the two pairs of terminals if you wish to take advantage of the bi-wire
facility.
The terminals can accommodate either stripped cable ends or 4mm plugs.Always
use good quality speaker cable with a 2.5mm
2
minimum cross sectional area per
conductor (79 strand). Cable of a smaller cross sectional area or fewer strands is
unsuitable. For cable runs longer than 10m use a significantly heavier gauge cable.
Consult your dealer or consultant for specific cable recommendations.
Ensure that the positive and negative terminals on each connection panel are
connected back to the corresponding positive and negative terminals on the amplifier.
2.4 Listening
The ear and brain tend to interpret distorted sound as loudness and thus
underestimate the actual level of undistorted sound.The C1 and C3, like all ATC
monitors, demonstrates very much lower levels of distortion than conventional
systems of a similar size and it is therefore advisable to begin listening at an
artificially low level and carefully increase the volume. It is also possible for the C1
and C3 to produce sufficient sound pressure levels for your ears themselves to
become a source of distortion and make the sound appear harsh. Any audible
distortion indicates that either the system or your ears are being overloaded and
that the volume level should be reduced.
C1/C3 Passive
6
Centre Speaker
Installation