JBL LSR6312SP - Manual (Page 14)

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Appendix: Wiring Recommendations
For optimum performance, some attention to wiring details can reduce system degradation. If you notice hum
present in the system when no audio signal is present, the following wiring recommendations can help.
Balanced Sources – The best way to run your system is balanced, where both “HOT” (+) and “COLD” (-) sig-
nals are supplied, as well as a GROUND/SHIELD. These are typically carried on two conductor shielded cables
with XLR connectors on both ends. Whenever possible, the cable shield should not be connected to any signal
pin, but left to perform a cable shielding function only.
Note: Under no circumstances should the safety ground wire be removed from the AC power connector.
When using balanced sources with the LSR6325P, it is recommended to use the XLR input on the LSR6325P.
This maintains a balanced signal and is the best way to reduce the possibility of hum or other interference.
For balanced sources, the “HOT” (+) signal from your source should be connected to Pin 2 of the XLR input as
shown in Diagram A. The “COLD” (-) signal should be connected to Pin 3 of the XLR. To avoid ground loops,
connect the SHIELD at the source end but not at the LSR input.
The LSR6325P was designed to output a level of 96 dB SPL at 1 meter with a +4 dBu signal applied to the
XLR input. If additional gain is required from a balanced output, Diagram B can be used with the RCA input.
The sensitivity of the RCA input is approximately 12 dB higher than the XLR input.
While there are only HOT and GROUND/SHIELD connections from unbalanced sources, it is recommended
that high quality twisted pair cable be used when using the XLR input of the LSR6325P. Diagram D shows
an unbalanced source connected to the balanced XLR input of the LSR monitor using twisted pair cable. Note
that the shield is connected to the GROUND/SHIELD connector at the LSR input, but not at the source. This
reduces the likelihood of introducing a ground loop into the system.
Diagram A
Diagram B