Shure KSM137/SL Cardioid Microphone

The KSM137 is an end-address condenser microphone with a single cardioid polar pattern. Designed for studio use, yet rugged enough for live applications, the KSM137 can withstand extremely high sound pressure levels (SPL). Its low self-noise and extended frequency response make it ideal for recording instruments. 

Versatile, durable, and precise, the KSM137 is an outstanding microphone for instruments ranging from percussion to wind, strings to brass, and piano to guitar.

Highly consistent cardioid polar pattern

Ultra-thin, 2.5 micron, 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

Subsonic filter eliminates low frequency rumble (less than 17 Hz) caused by mechanical vibration

Switchable 15 dB pad for handling extremely high sound pressure levels (SPLs)

3-position switchable pad (0 dB, 15 dB, and 25 dB) for handling extremely high sound pressure levels (SPLs)

3-position switchable low-frequency filter reduces background noise and counteracts proximity effect

 

Performance Characteristics 

Extended frequency response

Exceptional reproduction of low-frequency sounds

Can withstand high sound pressure levels (SPL)

Superior common mode rejection and suppression of radio frequency interference  

Common Applications 

Acoustic instruments -- such as piano, guitar, drums, percussion, strings

Wind instruments -- brass and woodwind

Low frequency instruments -- such as double bass, electric bass, kick drum

Overhead miking -- drums or percussion

Ensembles -- choral or orchestral

Room ambiance pick-up -- guitar amplifier or drums

Cartridge Type

Permanently Biased Condenser

Frequency Response

20 to 20,000 Hz

Directional Polar Pattern

Cardioid

Output Impedance

150 ohms (actual)

Attenuation Switch

0 dB, 15 dB, or 25 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 (IEC-268-15/DIN 45 596), positive pins 2 and 3

Current Drain

4.65 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

20 mm (0.8 in.) diameter, 122 mm (4.8 in.) long

100 grams (3.5 oz.)

Sensitivity (typical, at 1000 Hz; 1 Pa = 94 dB SPL)

-37 dBV/Pa

Self-noise (typical, equivalent SPL; A-weighted, IEC 651)

14 dB

Maximum SPL at 1 kHz

5000 ohm load (Attenuator on): 145 (160, 170) dB

2500 ohm load (Attenuator on): 139 (154, 164) dB

1000 ohm load (Attenuator on): 134 (149, 159) dB

Output Clipping Level*

5000 ohm load: 15 dBV

2500 ohm load: 9 dBV

1000 ohm load: 3 dBV

*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

Dynamic Range

5000 ohm load: 131 dB

2500 ohm load: 125 dB

1000 ohm load: 120 dB

Signal to Noise Ratio**

80 dB

**S/N ratio is difference between 94 dB SPL and equivalent SPL of self noise A-weighted.