The difficulty inherent in designing such loudspeakers is one of scale. Hi-fi levels of
accuracy and detail call for lightweight moving parts and delicate engineering.
Professional monitor levels of performance however demand far more robust
components engineered to survive the rigours of high level use for extended
periods.The only way to combine the two is through precision engineering of a class
and scale more often associated with aerospace or motorsport. But the results are
worth the effort and the cost. ATC loudspeakers, with their unique in-house
designed drivers, combine the best of hi-fi and professional to devastating effect.
ATC has become synonymous with active systems. Choosing to offer active
loudspeakers (where the passive crossover network is replaced by active filters and
multiple power amplifiers) is simply a result of the uncompromising attitude to
loudspeaker design.While passive systems still have their place, and ATC engineering
skills can still bring remarkable results from them, “active” is a fundamentally better
solution to the problems posed by accurate, high level music reproduction.The ATC
instinct is always for the better solution. Not cheaper, not quicker, but better.
It was the development of active loudspeakers that first brought ATC into
electronics design and engineering. Active speakers demand multiple power
amplifiers so ATC from the mid 1980s became not just a loudspeaker manufacturing
company but an electronics manufacturer too.The further step from electronics for
active speakers to a range of stand-alone amplifier products was natural and now
means that ATC engineering is available from the recording desk or CD player
output to the ears.
From modest beginnings ATC has grown to become one of the very few
manufacturers successful across both domestic and professional audio. By selecting
ATC you join a group of music lovers, professional audio engineers, studios and
musicians across the World that understand and value the engineering that goes into
an ATC product - and the sound that comes out.
2
I n s t a l l a t i o n
1 . D es c r i pt i o n
The SCM25/45/50/100/110 and 150 are a range of three
way loudspeakers. All of the range, excluding the SCM25
and SCM45 are available as passive or active units.
The SCM25 and SCM45 are only available as active
units. The product name suffix denotes the technology
featured in the product.
“SL” denotes Super Linear Magnet technology and “A”
denotes that the Loudspeaker includes active amplification.
Passive monitors are equipped with a “tri-wire” connection
panel to enable separate amplification of the bass, mid
and high frequency drivers. Active units have a built in
three way Amplifier with frequency, gain and phase
correction which has been individually optimised at the
ATC manufacturing facility. Adjustment of input sensitivity
and bass boost are available to the user via controls
on the rear panel of the unit.
2 . U np a c k i n g a nd H a n d li n g
The SCM25, 45, 50, 100, 110 and 150 are large heavy items
and should be handled with care. Always employ a
second person to assist in moving them. Unpacking is best
carried out on the floor, with adequate open space
around the carton, preferably close to their final position.
• Open the carton and remove all loose items.
• Remove the upper Sratocell foam cap.
• Remove the polythene or cloth bag, leaving
the baffle protector in place.
• Carefully lift the loudspeaker out from the
lower Sratocell foam cap using the handles
and the port opening as lifting points.
• The speaker can now be positioned in the
listening/control room
• Remove the baffle protector.
SCM50/100/15025/45/110/
3 . M on i t o r P l a c e m e nt
The subjective performance of any monitor loudspeaker will be influenced by the
acoustic character of the room in which it is used, and its position within the room.
Most often monitors are installed in rooms which are comfortable to sit and talk in.
A mixture of carpets, curtains and soft furnishings will 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 low frequency problems
the monitors should be kept away from corners or walls. Start with them positioned
on appropriate stands 1 metre from the side walls and 2 metres from the back wall
In professional installations, try to avoid placing speakers on the console/desk meter
bridge. Typically, this compromises the balance of the loudspeaker especially in the
lower mid range. If the balance is bass light, the monitors can be moved towards the
back walls.for fine tuning rather than to compensate forUse the Bass Boost control
innapropriate positioning. For stereo listening, loudspeakers should be positioned
so they form an equilateral triangle with the listening position (See Fig.1).
Loudspeaker stand height should be chosen to position the loudspeaker
acoustic axis at, or close to ear level (See Fig.2). All rooms vary and it is a good idea
to experiment with both the listening and speaker position until a good compromise
is reached. For professional installations the requirements are often very specific.
Please consult with an experienced professional acoustician if necessary. Monitors
Monitors with an asymmetric (offset) driver array should be positioned such that the
midrange driver and tweeter are inboard. If the monitors are to be placed in any form
of cabinet, adequate side and top clearance for cooling airflow must be provided.
Alternatively, the Amplifiers should be removed and installed remotely. All ATC 3-way
loudspeakers are designed with the mid-range dome as the reference acoustic axis.
With this in mind, the loudspeakers should be positioned with the mid-range dome
at, or slightly below ear level (See Fig.3).
Fig.2
Reference acoustic axis
Position at ear level or up
to 5 degrees above ear level
Loudspeaker Positioning - Stereo
distance z
30°
distance x
30°
distance y
Fig. 1
distance x = distance y = distance z
4 . L is t e n in g
The ear and brain tend to interpret distorted sound as loudness and thus
underestimate the actual level of undistorted sound. The SCM ,10025 45, 50,, 110
and 150, like all ATC monitors, demonstrate 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
SCM ,100and 150 to produce25 45, 50,, 110sufficient sound pressure levels for
your earsmake the sound appearthemselves to become a source of distortion and
harsh, Anyor your ears are beingaudible distortion indicates that either the system
overloaded and that the volume level should be reduced.
3
SCM50/100/15025/45/110/
Active monitors
I n s t a l l a t i o n
5 . S ig n a l C ab l e O pt i o ns
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.
Diagram 1 - input connection pins
PUSH
Pin 2, Signal (hot)
21
3
Pin 1, Screen
Pin 3, Signal (return)
6 . O pe r a t io n
Diagram 4illustrate the connection and controland 5panels for the Amplifiers
used in the active monitors. Each feature is described below.
Mains Inlet:
5.1
territory) should be connected here. Ensure that the mains voltage specified on
the panel corresponds with the local supply voltage.
5.2 Power Switch:
on the switch will illuminate.
5.3 Fuseholder:
operated the fuse should be inspected. Lift out the fuseholder cover using a
small flat-blade screwdriverth efuse and inspect it for damage. Ifremove
required a replacement fuse should be fitted,. It should be stressed however that
fuses most mostelectrical fault. If this is theoften fail only because of a serious
case then simply replacing thein another fuse failure. Thefuse will only result
monitor should be returned to ATC if a second fuse fails.
5.4
Input Socket:The audio signal cable should be connected here. Balanced or
or unbalanced cables may be used (See Section 3).
5.5
Bass Boost:
in the region of 40Hz. Use a small flat blade screwdriver to access the control.
Adds more warmth and energy to the lower frequencies in music,
at the expense of accurate transient reproduction.
Adjusting the bass boost without the ability to recalibrate may leave a
Note:
pair of monitors unmatched.
The supplied mains power lead (appropriate to the local
Switches on the monitor When.switched on the indicator
Should a monitor fail to switch on when the power switch is
Provides up to 6dB of gain (3dB for the SCM25 and SCM45)
Diagram 2 - balanced cable
3 Pin Male XLR
Connector
2
3
1
To Monitor Input
Two Core Screened Cable
Diagram 3 - unbalanced cable
3 Pin Male XLR
Connector
2
3
1
To Monitor Input
4
Two Core Screened Cable
3 Pin Female XLR
Connector
Hot
Return
Screen
To Source Output
Phono (RCA)
Hot
Return
Screen
To Source Output
2
1
Connector
LevelTrim : Provides access to an internal control that enables
5.6
adjustment of input sensitivity. Use a small flat blade screwdriver to access the
control. As supplied, monitors are calibrated to an input sensitivity of 1V.
Note:
Adjusting the sensitivity without the ability to recalibrate will leave a pair
of monitors unmatched.
3
Due to the nature of the electronics in ATC active loudspeakers it is quite normal
for a sound to be heard from the speaker when the power is applied or
disconnected. The noise heard will not damage the speaker and is quite normal.
Although ATC uses the highest-grade components, a different noise may be heard
from each speaker due to slight tolarance variations in the amplifier components.
7 . C on n e c ti o n
Two cable connections are required for each monitor: one for mains power and one
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 monitors in an alternative territory please contact ATC for advice.The mains
connection must always be earthed.
The signal cable and plug (not necessarily supplied) should be of a good quality and
XLR terminated. Poor cable and plug quality will compromise the performance of
your monitors.The signal input pin configuration is illustrated in Diagram 1.
I n s t a l l a t i o n
Passive Monitors
SCM50/100/15025/45/110/
8 . C on n e c ti o n
The monitors are equipped with a “tri-wire” connection
panel to enable separate amplification of the bass driver
mid driver and tweeter. Remove the linking bars between
the three pairs of terminals if you wish to take advantage
of the tri-wire facility.
The terminals can accomadate either stripped cable ends
or 4mm plugs: Always use good quality speaker cable with
a 2.5mm minimum cross sectional area per conductor
(79 strand). Cable of 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
9 .A mp l i fi c a t io 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:
• With any passive loudspeaker there is a trade-off between
low frequency extension and sensitivity. The monitors
extended low frequency response means that its 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 the system sounding
distorted 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 Super Linear technology and underhung
voice coil construction, the monitors 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 monitors
with your proposed amplifier and ancillary system.
Loudspeaker Positioning - 5.1 & 7.1 Surround
centre
right
distance RS
right
110°
150°
right
rear
side
left
150°
left
110°
distance LS
left
rear
sub
distance LR
distance C
distance L
30°
30°
distance R
distance RR
• All loudspeakers should be equi-distant from the listening position:
distance L = distance C = distance R = distance LS = distance LR = distance RR
• For 5.1 systems, position the ‘surround’ speakers between 110 and 150 degrees
• If ideal positioning is not possible, position loudspeakers as close as possible
to ideal
• Try to avoid placing the subwoofer on the mid-point between two walls
• For more details on setting up surround playback or monitoring systems
please contact you dealer or ATC direct.
3-way systems
acoustic axis: 5 belowº
mid-range driver
side
2-way systems
acoustic axis: mid point between
bass/mid and tweeter
5
SCM50/100/15025/45/110/
Diagram 4 -connection and control panelSCM25A and SCM45A Pro
+3dB
can only be safely used lower than 2,000 metres altitude
2000m
can only be safely used in non-tropical weather
bass boost
0dB (ref.)
model
Acoustic Transducer Co. Is a trading name and
Input sensitivity
(full output)
2v/8.2dBu
1v/2.2dBu (ref.)
serial no.
Is the registered Trade Mark of LoudspeakerTechnology Ltd.
Designed and manufactured by
Acoustic Transducer Company
Gloucestershire GL6 8HR
Tri - AmpPack
High Performance
Active Loudspeaker
Laite on liitettävä suojakoskettimilla varustettuun pistorasiaan
1:
2:
3:
voltage
Apparatet må tilkoples jordet stikkontakt
Apparaten skall anslutas till jordat uttag
WARNING
THIS EQUIPMENT
MUSTBE EARTHED
CAUTION
RISK OF ELECTRIC SHOCK
DO NOTOPEN
CHECKVOLTAGE BEFORE USE
NO USER SERVICEABLE PARTS INSIDE
I n s t a l l a t i o n
England
115/220 - 230V
fuse:
115V :T6.3A H/250V
220 - 230V :T3.15A H/250V
MAINS INPUT
50/60 Hz
POWER
CONSUMPTION
425WATTS MAX.
RETURNTO
MANUFACTURER
FOR DISPOSAL
Diagram-connection and control panel5 SCM50/100/110/150
Tri - AmpPack
High Performance
Active Loudspeaker
bass boost
+6dB0dB (ref.)
2v/8.2dBu
Input sensitivity
(full output)
1v/2.2dBu (ref.)
220 - 230V :T3.15A H/250V
RETURNTO
MANUFACTURER
FOR DISPOSAL
WARNING
THIS EQUIPMENT
MUSTBE EARTHED
CAUTION
RISK OF ELECTRIC SHOCK
DO NOTOPEN
100/115/220 - 230V
fuse:
100V :T6.3A H/250V
115V :T5A H/250V
Designed and manufactured by
fault
Acoustic Transducer Company
Gloucestershire GL6 8HR
balanced input
PUSH
2 1
3
model
6
England
Apparaten skall anslutas till jordat uttag
Apparatet må tilkoples jordet stikkontakt
Laite on liitettävä suojakoskettimilla varustettuun pistorasiaan
can only be safely used lower than 2,000 metres altitude
2000m
can only be safely used in non-tropical weather
serial no.
NO USER SERVICEABLE PARTS INSIDE
CHECKVOLTAGE BEFORE USE
Acoustic Transducer Co. Isa trading name and
!
MAINS INPUT
50/60 Hz
POWER
CONSUMPTION
625WATTS MAX.
voltage
Is the registered Trade Markof Loudspeaker Technology Ltd.
S p e c i f i c a t i o n s
SCM50/100/15025/45/110/
Active Monitors
Drivers:
HF
MF
LF
Amplitude Linearity ±2dB
Cut-off Frequencies
(-6dB free standing)
Matched Response
25mm (1")
75mm (3")
164mm (6.5")
7 Hz – 1 kHz47
47Hz & 22kHz
±0.5dB
SCM45A Pro
25mm (1")
75mm (3")
164mm (6.5")
70Hz – 1 kHz7
425Hz & 2 kHz
±0.5dB
Dispersion:
Horizontal
Vertical
Max Continuous SPL @ 1metre
Crossover Frequencies
±80° Coherent
±10° Coherent
1 dB09
±80° Coherent
±10° Coherent
1 dB12
380Hz and 3.5kHz, 4th order, critically damped with phase compensation
Input Connector
Input Sensitivity
1V rms (0dBV/1.1dBu) balanced (referenced to full output)
Sensitivity Trim
Input Impedance
Amplifier Output:
LF continous
MF continous
HF continous
Overload Protection
Bass Boost (40Hz continously variable)
Loudspeaker Dimensions
(HxWxD)mm
Pro
150 Watts
60 Watts
25 Watts
(
264 x 430 x 414
10.4 x 16.9 x 16.3
150 Watts
60 Watts
25 Watts
Activeomentary Gain Reduction on all.peak mchannels, r.m.s. power limiter on h.f. channels
0 to +3dB
353 x 600 x 414
13.9 x 23.6 x 16.3
(HxWxD)in.
Classic
Tower
OverallWeight
Pro
30.0kg (66lbs)
36.0kg (79.2lbs)
Classic
Tower
Power Requirements:
Voltage
Frequency
Internally set
115/220 - 230V
50/60Hz
Stands/Brackets
Cabinet Finishes
Specifications comply with the following standards: Australian Standard Specification No 1127 "Sound System Loudspeakers" Part 5,
E. & O.E. The policy of ATC is that of coninuous design and development.alterATC reserves the right toproducts and specifications without prior notice .
Acoustic Transducer Co. is a trading name and ATC is the registered trade mark of Loudspeaker Technology Ltd.
All products: Standard real wood veneers are available in Black Ash,Mahogany, Cherry and Natural Oak.
Other veneers and finishes can be supplied to special order.
SCM50ASLSCM100ASLSCM150ASLSCM25A ProSCM110ASL
25mm (1")
75mm (3")
234mm (9")
70Hz – 1 kHz7
38Hz & 2 kHz5
±0.5dB
±80° Coherent
±10° Coherent
112dB
Female XLR
0 to -6dB
10k Ohms per leg
200 Watts
100 Watts
50 Watts
)
Floor stands included with Hi-Fi products only
(
71 x 3 x 480651
28.2 x 13.8 x 18.932.8 x 15.7 x 22.928.2 x 24.6 x 19.734.8 x 19.6 x 24.7
71 x 3 x 480604
28.2 x 12.0 x 18.9
102034x 3 x 480
40.2 x 13.2 x 18.9
49kg (107. lb)8
49kg (107. lb)8
5316 8kg (1 . lb)
IEFE Specification Standard No 219-1975
25mm (1")
75mm (3")
314mm (12")
65Hz - 17kHz
32Hz & 25kHz
±0.5dB
±80° Coherent
±10° Coherent
115dB
200 Watts
100 Watts
50 Watts
832 x 398 x 581
832 x 398 x 581
32.8 x 15.7 x 22.9
1167 x 428 x 581
45.9 x 16.9 x 22.9
65kg (143lb)
65kg (143lb)
68kg (149.9lb)
100, 115,230V220 -
0 to +6dB
Internally set
50/60Hz
25mm (1")
75mm (3")
234mm (9")
65Hz - 17kHz
32Hz & 25kHz
±0.5dB
±80° Coherent
±10° Coherent
115dB
200 Watts
100 Watts
50 Watts
716 x 626 x 501
73kg (160.6lb)
25mm (1")
75mm (3")
375mm (15")
60Hz - 17kHz
25Hz & 25kHz
±0.5dB
±80° Coherent
±10° Coherent
117dB
200 Watts
100 Watts
50 Watts
)
884 x 498 x 628
884 x 498 x 647
34.8 x 19.6 x 25.5
1139 x 528 x 647
44.8 x 20.8 x 25.5
75kg (165.3lb)
75kg (165.3lb)
77kg (169.8lb)
7
SCM50/100/15025/110/
Passive Monitors
Drivers:
HF
MF
LF
Amplitude Linearity ±2dB
Cut-off Frequencies
(-6dB free standing)
Matched Response
Dispersion:
Max Continuous SPL @ 1 metre
Crossover Frequencies
Input Connector
Sensitivity @ 1 Watt/metre
Nominal Impedance
Recommended Power Amplifier:
Loudspeaker Dimensions
OverallWeight
Stands/Brackets
Cabinet Finishes
Specifications comply with the following standards: Australian Standard Specification No 1127 "Sound System Loudspeakers" Part 5,
E. & O.E. The policy of ATC is that of coninuous design and development.alterATC reserves the right toproducts and specifications without prior notice .
Acoustic Transducer Co. is a trading name and ATC is the registered trade mark of Loudspeaker Technology Ltd.
Horizontal
Vertical
(HxWxD)mm
(HxWxD)in.
Classic
Tower
Classic
Tower
All products: Standard real wood veneers are available in Black Ash,Mahogany, Cherry and Natural Oak.
Other veneers and finishes can be supplied to special order.
SCM50SL
25mm (1")
75mm (3")
234mm (9")
70Hz – 1 kHz7
38Hz & 2 kHz5
±0.5dB
±80° Coherent
±10° Coherent
112dB
380Hz and 3.5kHz, 4th order, critically damped with phase compensation
Binding Posts/4mm Sockets (Tri-Wire capable)
85dB
71 x 3 x 460425
28.2 x 12.0 x 16.7
10203425x 3 x 4
40.2 x 13.2 x 16.7
4190.4kg (lb)
4 kg ( . lb)599 2
Floor stands included with Hi-Fi products only
IEFE Specification Standard No 219-1975
SCM100SL
25mm (1")
75mm (3")
314mm (12")
65Hz - 17kHz
32Hz & 25kHz
±0.5dB
±80° Coherent
±10° Coherent
115dB
88dB
100 - 1500 Watts
832 x 398 x 526
32.8 x 15.7 x 20.7
1167 x 428 x 526
45.9 x 16.9 x 20.7
57.0kg (125.7lb)
61kg (134.5lb)
SCM150SL
25mm (1")
75mm (3")
374mm (15")
60Hz - 17kHz
25Hz & 25kHz
±0.5dB
±80° Coherent
±10° Coherent
117dB
9 dB1
8 ohms
884 x 498 x 592
34.8 x 19.6 x 23.3
1139 x 528 x 592
44.8 x 20.8 x 23.3
68kg (149.9lb)
70kg (154.3lb)
1 0 . C a r e a nd M a i n t e n an 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 speaker 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.
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.
1 1 . W a rr a n ty a n d C o n t a c t
All ATC products are guaranteed against any defect in
materials or workmanship for a period of two years
from th date of purchase. Within this periodewe will
supply replacement parts free of charge provided that
the failure was not caused by misuse, accident or
negligence.
Purchasers who complete and return the
Warranty Card will have their warranty period
extended up to a period of six years from the
date of purchase.This guarantee does not limit
statutory rights.
ATC can be contacted at:
Loudspeaker Technology Ltd, Gypsy Lane, Aston