Manual

ManualsBrandsATC ManualsloudspeakersSCS70 iW Pro - Active Subwoofer

The room in which a loudspeaker is placed can be thought of as a ﬁlter, altering the acoustic response at the listening position from that of the

loudspeaker. The position of the loudspeaker in a room will inﬂuence how it interacts with the space and therefore is often critical to achieving the

best performance at the listening position.

Positioning is particularly relevant to subwoofers because at low frequencies the room will have a strong inﬂuence due to room modes/resonances.

Room modes manifest themselves in an uneven distribution of acoustic energy within the room, which can lead to either too much or too little

bass at the listening position. A room with a well-controlled low frequency response (reverb time) will have a far smaller influence on the

performance of the subwoofer and will be less sensitive to subwoofer positioning. Typically, a combination of resonant membrane traps and

porous absorbers are needed to control the low frequency. The resonant membrane traps are effective at treating the low bass, typically below

80Hz and the porous absorbers frequencies above this. Porous absorbers such as those made from foams, ﬁbreglass or rockwool are not effective

at absorbing low bass energy without a very large air space between them and the wall behind. For this reason, they are a poor choice of absorber

for the subwoofer bandwidth.

To minimise problems a free-standing subwoofer should be kept away from corners where possible. Avoid placing the subwoofer mid-way between

any two parallel walls. Where the subwoofer is to be installed directly into a hard wall, as would be the case with the SCS70iW Pro, an increase in

LF efﬁciency and LF extension should be expected. In-wall loudspeakers are in the optimum position for exiting room modes between the mounting

wall and the opposite wall. The requirement for adequate bass trapping in the rear wall in this instance can be even more critical.

Start with the subwoofer positioned next to one of the stereo monitors and at the same distance from the listening position. When installing two

subwoofers, start with one by each of the stereo monitors. In most cases these guidelines will give the best results, however all rooms vary, and it

is a good idea to experiment with both listening and speaker positions until a good compromise is reached. When working on optimising the

positioning, only change one variable at a time.

Positioning the subwoofer in the centre of the room, equidistant from the two side walls and between the left and right stereo pair must be avoided.

In the majority of cases, this position will result in large irregularities in the frequency response.

Multiple subs will excite the room from multiple locations and will often give a more even in-room response. Also, a pair of subs can be placed with

the same physical relationship to the pair of main speakers and the listener.

Please see section 5 for recommendations on how to set the ampliﬁer ﬁlters and level.

For professional installations the requirements are often very speciﬁc. Please consult with an experienced professional acoustician if necessary.

The SCS70iW Pro cabinet features a rear mounted recessed input panel containing a NL4 High Level Audio Input Socket and a 5-pin XLR socket

for connection to the front panel LED’s. The sockets are to be wired back to the R1-300 Rack Mount Ampliﬁer using the cables supplied by ATC,

but not included with the subwoofer. The SCS70iW Pro does not require ventilation behind the cabinet and can be installed directly into a wall.

The front face of the bafﬂe should sit ﬂush with the face of the wall.

The R1- 3 0 0 Rack Mount Ampliﬁer is to be mounted in a 19” equipment rack. The heatsink must not be covered and should have adequate ventilation.

The ampliﬁer can also be mounted in the control room wall, close to the subwoofer if required. Always try to minimise the lengths of speaker cables

between power amps and loudspeakers/subwoofers. Cable lengths under 5m are preferable and lengths over 10 m should be avoided where possible.

SECTION THREE

Room Interaction

SCS70iW Pro & R1–300 Remote Amplifier Installation

Subwoofer Placement

3.1

3.3

3.2

Diagram 1 – R1-300 LED and signal wiring

DIAGRAM 1 – R1-300 LED AND SIGNAL WIRING

Speaker Output

Power/Limit & Mute Indicator

LED Output

1: bass - on/green

2: bass - limit/red

3: mute - blue +

4: mute - blue -

5: not used

Green

Red

Blue

O/P Connections

1+/1- : bass +/-

Minimum Speaker Cable Requirements

Use 14G / 2.5mm2

stranded OFC cable for runs up to 5m / 16 feet.

Use 12G / 4.0mm2 s

randed OFC cable for runs over 5m / 16 feet.

R1-300 Pro

1-Channel Remote Amp Pack