SM27 Spec Sheet (PDF, English)

Cartridge Type
Externally Biased Condenser

Frequency Response
20 to 20,000 Hz

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Directional Polar Pattern
Cardioid

Output Impedance
EIA Rated at 150 ohms (140 ohms actual)

Attenuation Switch
0 or 15 dB attenuation

Low Frequency response switch
Flat
-6 db/octave below 115 Hz
-18 dB/octave below 80 Hz

Phantom Power
48 Vdc +/- 4 Vdc (IEC­268­15/DIN 45 596), positive pins 2 and 3

Current Drain
5.4 mA typical at 48 Vdc

Common Mode Rejection
>50 dB, 20 Hz to 20 kHz

Polarity
Positive pressure on diaphragm produces positive voltage on output pin 2 relative to pin 3

Dimensions and Weight
53.0 mm (2.08 in.) maximum body diameter
156.2 mm (6.15 in.) long;
642 grams (22.6 oz.)

Sensitivity (typical, at 1000 Hz; 1Pa = 94 dB SPL)
-37 dBV/Pa

Self­noise (typical, equivalent SPL; A­weighted, IEC 651)
9.5 dB

Maximum SPL (1000 Hz at 1% THD)
2500 ohm load (Attenuator on): 138 (153) dB
1000 ohm load (Attenuator off): 133 (148) dB

Output Clipping Level*
2500 ohm load: 7 dBV
1000 ohm load: 1 dBV

Dynamic Range
2500 ohm load: 128 dB
1000 ohm load: 123 dB

Signal to Noise ratio**
84.5 dB

*20 Hz to 20 kHz; THD < 1%. THD of the microphone preamplifier when applied input signal is equivalent to the cartridge output at specified SPL.
**S/N ratio is difference between 94 dB SPL and equivalent SPL of self-noise A-weighted.