Cardioid Condenser Microphone

The Shure SM Microphones Series SM-137 is a versatile, flat-response cardioid condenser probe microphone.

The SM 137 has 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.

→ Ultra-thin, 2.5 µm 24 karat gold-layered, low mass Mylar diaphragm for superior transient response
→ Class A, discrete, transformerless preamplifier for transparency, extremely fast transient response, no crossover distortion, and minimal harmonic and intermodulation distortion
→ Premium electronic components, including gold-plated internal and external connectors
→ Two-position switchable pad (0 dB and 15 dB) for handling extremely high sound pressure levels

Type	Electret Condenser
Frequency Response	20 to 20,000 Hz
Polar Pattern	Cardioid
Impedance	150 O (actual)
Sensitivity (at 1 kHz, open circuit voltage)	-41 dBV/Pa; 1 Pascal=94 dB SPL
Maximum SPL (1 kHz, < 1% THD)	1000 O load: 139 dB (154 dB, Pad on); 2500 O load: 144 dB (159 dB, Pad on)
Signal-to-Noise Ratio (referenced at 94 dB SPL at 1 kHz)	75 dB; S/N ratio is difference between 94 dB SPL and equivalent SPL of self noise, A-weighted
Dynamic Range (at 1 kHz)	1000 O load: 122 dB; 2500 O load: 128 dB
Common Mode Rejection (20 Hz to 20 kHz)	> 50 dB
Clipping Level (20Hz-20 kHz at 1% THD)	1000 O load= 3 dBV; 2500 O load= 9 dBV; THD of microphone preamplifier when applied input signal is equivalent to cartridge output at specified SPL
Self Noise (typical, equivalent SPL, A-weighted)	19 dB
Polarity	Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3
Weight	Net= 195 g (8.9 oz.)
Switch	Attenuator= -15 dB
Dimensions	162 mm (6.375 in.) L x 24 mm (0.950 in.)
Connector	Three-pin professional audio (XLR), male
Power Requirements	48 Vdc phantom, 5.2 mA polar pattern to reduce the pickup of unwanted sounds