Activating Ground Lift - Neumann.Berlin KH 120 A Operating Manual

If a video delay compensation has already been made, add the time-of-fl ight diff erence
(here: 0 .4 ms) to the setting already made .
Example
Video delay compensation on loudspeaker A:
Desired time-of fl ight compensation for loudspeaker A:
Time-of-fl ight compensation:
This delay value can be made with these switch settings: 3 x 25 .6 ms, 2 x 1 .6 ms, 4 x 0 .1 ms .
The latency of the analog-to-digital and digital-to-analog converters should be
taken into account when using the DELAY rotary switches E for time-of-fl ight com-
pensation . For the digital-to-analog conversion (input signal via digital connector),
the latency is dependent on the sample rate (values can be seen in the Specifi ca-
tions table on page 18) . The analog-to-digital-to-analog conversion (input sig-
nal via analog connector) is fi xed at 0 .54 ms .
For time-of-fl ight compensation delay, calculate the desired delay value then sub-
tract the appropriate latency depending on the input signal and sample rate, and
then set the needed additional delay using the delay switches on the back panel .
Example:
Distance compensation for 1 m: 1 m / 344 m/s = 2 .91 ms: 2 .91 ms
Digital input signal, sample rate: 48 kHz, latency:
Delay settings:
0 x 25 .6 ms, 1 x 1 .6 ms, 5 x 0 .1 ms
(equals 2 .1 ms, which is the nearest value)
For video delay compensation, converter latency can be ignored as it is insignifi -
cant compared to long video signal delays .
To help with choosing a delay setting there is a set of lookup tables at the end of
this operating manual . Also Neumann has made a delay calculator which is avail-
able at www .neumann .com .

Activating ground lift

If there is humming or buzzing noise coming from the loudspeaker, fi rst search for the cause of
the noise:
Disconnect all input and output signal cables from the loudspeaker .
X
If the noise goes away, it is probably coming from the audio source or source cabling .
It might be possible to eliminate the noise by disconnecting the ground from the input signals
(activating ground lift) .
To activate ground lift:
Reconnect the signal cables and set the DIP switch [4] ("Ground lift") 5 to "Lift" .
X
This internally disconnects pin 1 of the ANALOG INPUT socket (XLR) 6 from the loudspeak-
er's chassis ground (see diagram "Pin assignment of the XLR socket" on page 9) .
For safety reasons, the electronics chassis ground is always connected to the mains
power earth pin .
KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D KH 120 D
2 x 40 ms/frame
0 .4 ms
80 .4 ms
0 .85 ms
2 .06 ms
KH 120 | 15
EN