Whirlwind SP1X3 1X3 Microphone SplittersWhirlwind SP1X3 1X3 Microphone Splitters The SP1X3 provides one direct and one or two transformer isolated outputs, respectively, from a mic level input. The SP1X2 provides one direct and one isolated output while the SP1X3 provides one direct and two isolated outputs. Each transformer isolated output on these devices features a ground lift switch. Key Features Operating Level: 0. 5dB to +4dB Frequency Response: 20Hz 20kHz 0. 63dB Max input level: 0.