The ADK A-51s Condenser Microphone is designed for use in studios, concert halls and for broadcast applications. S is for SPL! Vocals, Choirs, Acoustic Guitar, Fretted Instruments (Banjo, Mandolin, Dobro, etc.), Reeds and Woodwinds. Plus: Drums Especially Floor Toms, Drum Overheads; Electric Guitar and Bass, All Percussion Instruments, Piano. In short, the "S" will do anything the A-51 does PLUS it is designed for high SPL applications. They are well-known for their wide frequency response, smooth response curve, large dynamic range and low distortion. Both the A-51 and A-51S feature a 1" Gold Sputtered Diaphragm and discrete Class A electronics featuring a transformer coupled balanced output. Mellow enough for Nashville, just enough shimmer for NY & LA.