When an audio signal is too powerful it can overload the sensitive circuitry of the microphone (especially when using ribbon mics), resulting in uncontrollable distortion. For example, consider the high Sound Pressure Levels produced by trumpets and saxophone, or electric guitar cabinets.
Some microphones, mixing desks and audio interfaces have in-built attenuation (pads) but some don't and this is where ST-PAD/PHASE can be used to save the day!
ST-PAD/PHASE provides attenuation via two switchable -10dB stages, providing you with ample assistance to tame powerful audio signals.
There is also a -180° phase inversion switch which can be very helpful when you have microphones placed in close proximity to the sound source and phase-correlation is a problem. A common example is when miking the top and bottom of a snare drum - simply plug in ST-PAD/PHASE to one of the mics and invert the phase for fantastic, phase-accurate results.