The Sterling Audio ST55 is an FET condenser microphone that employs a large capsule with an ultra-thin 3-micron evaporated gold Mylar diaphragm. The ST55 mic is built with an exclusive process that extends high frequencies and improves details and depth on both vocal and instrument recordings. The FET Class-A electronics provide smooth, warm sound.Sterling Audio microphones employ several advanced technologies that separate their large-diaphragm condenser mics from the rest of the pack. One of the more important advancements is their Disk Resonator system. With it, Sterling Audio is uniquely able to compensate for the 14kHz frequency roll-off that is inherent in large diaphragm mics. As any good audio engineer knows, this deficiency translates to a lack of sparkle from high-frequency sound sources. Other manufacturers have typically solved this problem by cutting other frequencies and then increasing the entire signal to help even out the frequency range. Unfortunately, this results in increased noise. Disk Resonator Technology incorporates a brass umbrella that protrudes from the center of the diaphragm in Sterling Audio's ST55 microphone. It gently boosts the diaphragm sensitivity to shorter sound waves, allowing it to respond more accurately to those all-important higher frequencies. The result is optimal sensitivity, full frequency response, and a low signal-to-noise ratio. Another piece of audio wizardry comes in the form of the ultra-thin diaphragm membrane made of Mylar. While most modern condenser diaphragms are 6 to 12 microns in thickness, Sterling Audio, in association with 3M, has produced a highly resilient Mylar that measures a mere 3 microns. This allows the ST55 to deliver an extraordinary degree of sensitivity. Requires phantom power.