Whirlwind SP1X2 - 1x2 Mic Splitter

The Ground/Lift switch disconnects the ground between the input and the output when it is set to the "Lift" position. The ground remains connected when the switch is set to the "Ground" position. The Direct Output provides a direct connection between the input and output (without the transformer), and always has a connected ground. Additionally, the Direct Output will allow phantom power to be passed through to the mic. The Isolated Output provides a balanced, low impedance signal (150 ohms) which goes through the Whirlwind TRSP transformer. The transformer blocks phantom power and prevents it from passing through to the mic.

In order to use the Whirlwind SP1X2 1x2 Mic Splitter with a microphone that requires phantom power, you will need to use a separate phantom power supply or preamp with phantom power to supply power to the mic, and then you can connect the output from the phantom power supply to the splitter. As examples of a phantom power supply, you can use the Mackie M48 Single-Channel 48V Phantom Power Supply (B&H # MAM48), which can be powered using the included AC adapter or with a 9V battery, or the Xvive Audio P1 Portable Phantom Power Supply with Rechargeable Battery (B&H # XVP1), which has a built-in rechargeable battery.

I agree that you might want a line level split instead of this mic level split but only if you're using powered speakers. If that's the case you won't need to worry about impedance matching because that would only apply at speaker level between an amp and a passive unpowered speaker. Line level and mic level signal can be split without impedance concerns.

The direct output is a pass thru, just wires connected from input to output. The isolated output has a transformer between them so the signal is separated from the input and signal flows only one direction as opposed to a non-isolated splitter which is essentially just a Y cable. If using a mic requiring phantom power, you would want the direct output connected to the mixer providing phantom power.