Large Dual-Diaphragm Vocal Microphone

Premium cardioid condenser microphone with capsule ideal for world-class vocal recording.


Dual-diaphragm cardioid microphone delivers exceptionally smooth proximity control and ultra-wide dynamic range. It features a natural off-axis response, a dual-diaphragm with a gold Mylar diaphragm, 3-stage grille, and internal shock mount.


  • Highly consistent cardioid polar pattern creates a broad “sweet spot” and natural off-axis response
  • Prethos® Advanced Preamplifier Technology exhibits extremely low self-noise with superior dynamic range, transient response and ultra-low distortion for transparent recording
  • Dual-diaphragm design with an active front, ultra thin (2.5 micron) 24-karat gold, low mass, 1-inch Mylar® diaphragm
  • Passive back diaphragm delivers exceptional control of low frequency proximity effect
  • Tailored low-frequency roll-off minimizes low frequency room noise
  • Integrated three-stage mesh grille guards against wind and breath noise
  • Open cage ShureLock® rubber suspension shock mount with low-profile Popper Stopper™  magnetic pop filter produces a natural space between performer and microphone
  • Extremely low self noise for critical studio vocal recording
  • Premium electronic components and gold-plated internal and external connectors
  • Durable zinc die-cast housing and hardened low carbon steel grille
  • Internal shock mount to reduce unwanted handling and stand noise

Shure KSM42: Large Dual-Diaphragm Microphone


Transducer Type

  • Dual-Diaphragm, Front-Active, Externally Biased Condenser

Frequency Response

  • 60 to 20,000 Hz

Polar Pattern

  • Cardioid

Output Impedance

  • 147 ohms

(at 1 kHz, open circuit voltage)

  • −37 dBV/Pa (14.1 mV)
  • 1 Pascal=94 dB SPL

Maximum SPL
(1 kHz at 1% THD)

  • 1000 ohms load: 139 dB
  • 2500 ohms load: 139 dB

Signal-to-Noise Ratio
(referenced at 94 dB SPL at 1 kHz)

  • 86 dB
  • S/N ratio is difference between 94 dB SPL and equivalent SPL of self noise, A-weighted

Dynamic Range
(at 1 kHz)

  • 1000 ohms load: 131 dB
  • 2500 ohms load: 131 dB

Common Mode Rejection
(10 Hz to 100 kHz)

  • > 60 dB

Clipping Level
(20Hz-20 kHz at 1% THD)

  • 1000 ohms load: 6.5 dBV
  • 2500 ohms load: 8 dBV

Self Noise
(typical, equivalent SPL, A-weighted)

  • 8.5 dB


  • Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3

Weight Net:

  • 494 g. with shock mount and pop filter: 820 g


  • Three-pin professional audio (XLR), male

Power Requirements

  • 11 to 52 Vdc phantom, 6 mA

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