More about splitters
24
Square ONE Splitter
Passive parallel splitter
The passive parallel splitter has, basically, all of the ‘split’ points wired in parallel, offering no ground isolation
or any gain stage whatsoever. Passive parallel splitters are popular at the lower end of the market as they
provide a very cost-effective solution as compared with a transformer isolated splitter or an active splitter.
There are four fundamental problems inherent in a passive parallel type splitter:
•
Mic signals are typically very low level (-40dB), with the gain being added at the mixing console. Due to
the nature of a passive parallel splitter system the cable runs carrying the mic signal end up being quite
long, increasing their susceptibility to picking up additional noise from other sources, for example, stray
mains cables that may induce hum. In turn, this additional noise also gets amplified along with the
original mic signal.
•
The lengthy mic cable runs also significantly increase capacitance, which in turn reduces the high
frequency content making the sound dull and uninspiring. Also, the input impedance of each console
added to the system will reduce the overall level.
•
Phantom powered mics are normally supplied via two 6k8 ohm resistors. If addi48V sources are
enabled in parallel this increases the current and voltage, potentially damaging the mic.
•
The grounding regime is basically one complete ground with no option of isolating various parts of the
system. This can potentially lead to ground loop problems if parts of the system are powered from
different sources. For example, the PA company may have set the whole system up perfectly using one
grounding regime, an independent broadcaster then arrives and has to use a portable generator, adding
another grounding source.
FOH console
(for example, the
Midas Verona)
MON console
(for example, the
Midas Siena)
PA company responsibility
Independent broadcaster
Sensitive audio signals
Grounds
Local
Ground
Local
Ground
Stage box (passive)
-40dB (0.01V)
-40dB (0.01V)
-40dB (0.01V)
-40dB (0.01V)
Outside
Broadcast
