Ground
pin 1
Screen (S)
If the source itself has a balanced output, use shielded twin conductor cable
(microphone cable) connecting pin 2/T to pin 2/T, pin 3/R to pin 3/R, and pin 1/S to pin
1/S (using the shield).
If the source has an unbalanced output, a single conductor shielded cable can be used,
connecting pin 2/T of the input to the “hot” signal pin of the source, while pin 3/R and pin
1/S should be linked together and connected to the source signal ground.
Controls and indicators.
The input level switch (location 5) provides a sensitivity (i.e. gain) adjustment, the top
and bottom positions corresponding respectively to -10 dBu and +4 dBu nominal
sensitivities. The position of the input level switches should be identical on each monitor
for correct channel balance.
When set to ‘Free space’, the LF Contour facility (location 6) extends the bass response
and enhances the low frequency content below 150 Hz by means of a Hi-Q 2nd order
Hi-Pass filter. In the ‘Half space’ position the LF signals are unprocessed and the bottom
end response remains that of a vented system i.e. a 4th order (24 dB/octave). Note that
when activating the Hi-Pass filter (‘Free Space’), very low frequencies under 30 Hz will
be significantly attenuated so that mechanical stress on the LF drive unit (excursion) is
maintained within safe operating limits. Also, the boost applied to the signal in the ‘Free
space’ position will reduce the headroom on the LF amplifier channel and therefore the
maximum SPL available.
The HF Contour switch (location 7) allows adjustment of the HF level. Its operates as a
shelving filter above 2 kHz with -2 or +2 dB amplitude and a 0 dB (flat) middle position.
Use this facility if you feel that a flat response is not the most appropriate to the
acoustical environment, and that the HF level requires adjustment.
Use close to TV screens and video monitors.
The cabinet construction incorporates metal plates which provide a degree of shielding
against the magnetic field created by the drive unit. The speakers can be therefore used
relatively close to TV screens without any picture distorting effect. However some
precautions must be taken, depending on which side of the speaker is located close to
the screen. The diagram below gives an indication of the distance required between
each side of the cabinet and the screen nearby. The figures are based on an emitted
stray field not exceeding 0.3 mT (300 Gauss), usually considered as a safe value.
However, as magnetic sensitivity varies from one screen to another, you are strongly
advised to check before making any permanent installation.
Distance required
≥
6 cm
Distance required
≥
= 0
Distance required
≥
6 cm
Distance required
≥
13 cm
Figure 2. Safe distance for magnetic immunity
Содержание System 800A
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