Mic splitters 101: active vs transformer vs resistor

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Joined: 02/12/2009

Here's a quick intro on microphone splitters and how to use them.

If you are a performer, engineer, concert producer or anyone involved with a PA system (including anyone doing a live audio recording), it's essential to know this cornerstone element of a live sound system. A mic splitter does as it's named: it splits the mic-level signal to two or more directions.

Much better than a simple y-cable, a splitter ensures that the same signal is received everywhere without compromising audio quality or electrical grounding (earth). It also avoids loading down the mic as a y-cable would.

There are four main categories of mic splitters: resistor-based, tranformer-isolated, active and digital. Note that some active splitters can have the outputs transformer-coupled. The following is a feature comparison (Digital splitters are pretty new and expensive, so are not covered here yet):

• ground isolation
active: Y
transformer: Y
resistor: N

• blocks phantom power on isolated feeds (but not on the direct feed)
active: Y
transformer: Y
resistor: N

• stops impedance loading
active: Y
transformer: NO (**Note this, which was a surprise to me!)
resistor: N

• common mode rejection
active: BEST
transformer: GOOD
resistor: POOR

• cost
active: $$$
transformer: $$
resistor: $
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