5 : C o n n e c t i o n
The SCM12 Pro monitor is equipped with a “bi-wire” connection
panel to enable separate amplification of the bass/mid driver and
tweeter. The connection panel is shown in Fig. 4.
If not bi-wiring, connect your speaker cable to either the upper
or lower horizontal pair of terminals. Should you wish to take
advantage of the bi-wire facility remove the linking bars, between
vertical pairs of terminals. The upper horizontal pair of terminals
are connected to the tweeter. The lower horizontal pair are
connected to the bass driver.
Terminals can accommodate either stripped bare cable ends,
4mm banana plugs or spade terminals. Do not use crimps on the
bare wire ends as the difficulty in compressing them can cause
poor link bar connection.
Always use a good quality speaker cable with 2.5mm
2
minimum
cross sectional area per conductor (79 strand). For cable runs
longer than 5 metres 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 to the corresponding positive
and negative terminals on the amplifier.
A lack of bass output and very wide unstable stereo image is
most likely caused by the left and right loudspeakers being
connected out of phase. If the system displays these
characteristics, please check the polarity of the wiring.
6 : A m p l i f i c a t i o n
The choice of partnering amplifier for the monitors will have
significant influence on the performance of the system. Consider
the following when selecting the amplifier:
n
With any passive loudspeaker there is a trade off between
low frequency extension and sensitivity. These monitor’s
extended low frequency response means the sensitivity is
relatively low. It is therefore advisable to select a power amplifier
of relatively high power output capabilities. Typically, best
performance comes with use of amplifiers capable of >150W
continuous into 8 ohms.
n
Use of an underpowered amplifier will result in the
premature distortion of the system and increased risk of damage
due to voice coil overheating
n
Valve or solid state amplifiers with high output impedances
should be auditioned carefully, to establish that their
characteristic reduced damping factor at low frequencies is
acceptable.
7 : L i s t e n i n g
The ear and brain tend to interpret distorted sound as loudness
and thus underestimate the actual level of undistorted sound.
The SCM12 Pro, like all ATC monitors, demonstrate very much
lower levels of distortion than conventional systems of a similar
size. It is therefore advisable to begin listening at an artificially
low level and carefully increase the volume. It is also possible for
the SCM12 Pro 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 volumes should be reduced. The user should also bear in
mind that the monitoring level in a professional environment
can change the way certain sounds are perceived and that for
consistent high quality results, consistent and moderate
monitoring levels should be used.
8 : C a r e & M a i n t e n a n c e
High technology material finishes are used in this product.
The surfaces are durable and with a little care can be kept as
good as new even under conditions of heavy use. Normally, a
dry duster will be all that is required to keep the finishes clean.
Heavy soiling can be cleaned using a cloth slightly moistened
with a non-abrasive household cleaner.
There are no components within the speakers that can be
considered expendable, or that would benefit from regular
maintenance. There is no requirement for any kind of routine
service work and there is no schedule for preventative
maintenance.
Fig. 4
SCM12 Pro Passive Input Panel
There are no user-replaceable parts within the speaker and,
in the unfortunate event of any malfunction, repair should be
referred to either the supplying dealer or consultant, the
relevant importer, or ATC.
ATC has every confidence in the quality of each product that
it manufactures.
9 : S p e c i f i c a t i o n s
Drivers
HF ATC 1˝/25mm dual suspension Soft Dome (SH25-76 6 Ohm)
LF ATC 6˝/150mm Constrained Layer Damping (CLD) (SB50-150CLD 8 Ohm)
Amplitude Linearity
80Hz - 16kHz (+/-2dB)
Cut Off Frequencies
56Hz - 22kHz (-6dB freestanding)
Dispersion
±80° Coherent Horizontal, ±10° Coherent Vertical
Maximum Continuous SPL
108dB (per pair @ 1m)
Crossover Frequency
2.2kHz
Recommended Power Amplifier
75 to 300 Watts
Nominal Impedance
8 Ohm
Connectors
Binding Posts/4mm Plugs, bi-wire
Cabinet Dimensions (HxWxD)
400x238x235mm/15.7˝x9.4˝x9.3˝
Weight :
11kg/24lbs (per cabinet)
