SM137 Condenser Instrument Microphone

The SM137 is a versatile, flat-response cardioid condenser probe microphone with an ultra-thin diaphragm for a frequency response that combines a smooth high-end with a tight, controlled low-end and a 15db pad for natural sound reproduction in both acoustic and high volume performance applications

Versatile, flat-response cardioid condenser microphone in both acoustic and high volume performance applications.

• Ultra-thin diaphragm for smooth high end and tight, controlled low end
• 15dB pad for performance consistency across a wider range of high SPL sources
• Low self-noise and transformerless preamplifier circuitry

SM137 Spec Sheet (PDF - English)

Cartridge Type
Permanently Biased Condenser

Frequency Response
20­ to 20,000 Hz

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Directional Polar Pattern
Cardioid

Output Impedance
150 ohms (actual)

Attenuation Switch
0 dB or 15 dB attenuation

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

Current Drain
5.2 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
24 mm (0.950 in.) diameter
162 mm (6.375 in.) long
195 grams (6.9 oz.)

Sensitivity (typical, at 1000 Hz; 1 Pa = 94 dB SPL)
-41 dBV/Pa

Self­noise (typical, equivalent SPL; A-weighted (IEC 651))
19 dB

Maximum SPL@ 1000 Hz
5000 ohms load (Attenuator on): 150 (165 dB)
2500 ohms load (Attenuator on): 144 (159) dB
1000 ohms load (Attenuator on): 139 (154 dB)

Output Clipping Level*
5000 ohms load: 15 dBV
2500 ohms load: 9 dBV
1000 ohms load: 3 dBV

Dynamic Range (Attenuator On)
5000 ohms load: 133 (136) dB
2500 ohms load: 128 (130 dB)
1000 ohms load: 122 (125) dB

Signal to Noise Ratio**
75 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.