Digital Monitoring Products 7073A Specifikace stáhnout pdf (Strana 3)

"master" subwoofer in a daisy-chained

multiple subwoofer configuration. Note

that the "subwoofer out" channel of an

analogue matrix surround decoder (Dolby

Surround, Dolby Pro Logic) should not be

connected to the "LFE IN" input. See sec-

tion "Subwoofer in analogue matrix sound

systems".

SUM OUT: Use this output connector

when you want to link another subwoofer

to your system. "SUM OUT" carries an

unfiltered sum of signals combined from

all input channels. See section "Using

multiple subwoofers".

Middle row

FRONT L, C, R CHANNELS IN/OUT: Use

these connectors for the Front Left, Center

and Right channels of a surround sound

system or the Left and Right channels of

a Stereo system. Connect line level signal

cables from your signal source to their

respective "LEFT IN", "CENTER IN" and

"RIGHT IN" connectors. Then connect the

subwoofer to your main monitors with XLR

cables from the "LEFT OUT", "CENTER

OUT" and "RIGHT OUT" connectors. All

"L, C and R OUT" channels are high pass

filtered with the filtering frquency fixed at

85 Hz (12 dB/octave).

Bottom row

REAR L, C, R CHANNELS IN/OUT: Use

these connectors for the Rear Left, Center

and Right channels of a surround sound

system. The connection is made in the

same way as with the Front channels. The

rear channels are also high pass filtered

at 85 Hz.

Once all connections have been made,

the subwoofer and main monitors are

ready to be powered up.

Positioning in the room

The placement of the subwoofer in the room

affects the overall frequency response and

sound level of the system dramatically, as

at low frequencies the effects of the room

are strong. Even a slight change in the sub-

woofer's location can make a marked dif-

ference in the frequency balance and often

patient and methodical experimentation

and testing is needed to find the optimum

placement.

The placement will affect the phase dif-

ference between the main monitors and

the subwoofer, and also the bass roll-off

rate. These effects can be compensated

by the use of the controls in the amplifier

unit; but we recommend that at first you

leave the switches untouched and con-

centrate on finding the position where the

subwoofer gives the smoothest response,

and only then use the controls to fine-tune

the balance and phase alignment between

the subwoofer and the main monitors.

To begin with, place the subwoofer

slightly offset from the center of the front

wall. The recommended distance to the

wall is less than 60 cm / 24" measured

from the subwoofer's drivers. This posi-

tion gives increased acoustic loading (and

SPL) due to the proximity of the front wall

and floor and avoids low frequency can-

cellation and comb filtering. Front wall can-

cellation for the 85 Hz high pass filtered

main speakers can be eliminated by plac-

ing them at least 110 cm / 43" away from

the front wall. In a multichannel system the

main monitors should ideally be positioned

symmetrically and at an equal distance

Figure 1. 7073A's connector panel, connectors and controls.

Figure 2. XLR to RCA connector for

unbalanced operation.

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