The A51/S51 is a modern German EQ’ed large-diaphragm condenser mic. It is a wonderful “do everything” mic for any studio. You will love it on Acoustic Guitar, Fretted Instruments, Drums, Bass Cabinets, Piano and many other instruments. “From Nora Jones viola parts to James Taylor guitar parts, we were amazed at how many uses we had for the ADK “S” microphone! We had 22 ADK Mics on Ray Charles’ Genius Love Company CD” (Terry Howard: Multiple Grammy Winner (Ray Charles, Gladys Knight, Willie Nelson) The S-51 is the higher SPL “Big Brother” to the A-51. It incorporates a -10 dB switch and a 100 Hz roll-off switch on the body. End-users of ADK Audiophile Mics are a Who’s Who of the Music World for good reason. The ADK Audiophile series of condenser mics were created for critical recording environments and fine acoustic sources. When your tracks really matter, ADK Audiophile Series delivers Stellar Performance at affordable prices. Founders Larry Villella and Brian Hutchison founded ADK in 1998. Their partnership with a Belgian design wizard and a PhD from Australia resulted in a range of superb microphones that quickly became favorites of engineers, artists and producers. 11 years and 50,000 microphones later, ADK is tracking TV shows, movies, and CDs all over the world! Why are ADK Mics so popular? Because ADK creates world-class microphones that superstars adore, yet are philanthropically priced so the average guy can afford them. Specs: Type: Class A Pressure Gradient FET Condenser Microphone; Polar Pattern: Fixed Cardioid; Sensitivity: 15mv/Pa; Impedance: 200 Ohms; S/N Ratio: 77dB (Ref: 1 Pa / A-Weighted); Equivalent Self-Noise: 17dB (A-Weighted / IEC 268-4); Max; SPL @ 0.5% THD: 130dB; Total Dynamic Range: 113 dB; Low-Cut Filter (HPF): Flat / 100Hz (external switch; Power Requirement: Phantom Power 48V ± 4V, Body color: Silver