SM31FH Fitness Headset Microphone

The Shure SM31FH is a water-resistant headset microphone for use with a wireless bodypack transmitter. It is ideal for fitness instructors and in situations where the microphone may be exposed to moisture.

Wearing the Microphone

  1. Install the windscreen on the microphone boom.
  2. Place the headband around the back of the head, with the boom on the left side.
  3. Place the microphone at the corner of the mouth. To decrease pops and plosives, avoid placing the microphone directly in front of the mouth

Maintenance and Cleaning

  • If the microphone is exposed to perspiration, remove the windscreen and gently wipe the microphone underneath with a damp, non-abrasive cloth. Allow the microphone to air dry before replacing the windscreen and storing.
  • The windscreen can be washed with a mild antiseptic, and should be fully rinsed and dried before reinstalling on the microphone. Do not use alcohol-based disinfectants.



Electret Condenser

Frequency Response

45 Hz to 20,000 Hz

Polar Pattern

Unidirectional (Cardioid)

Output Impedance

@ 1 kHz

600 Ω

Audio Output Level

-50.0 dBV/Pa

Signal-To-Noise Ratio [1]

@ 1 kHz

66 dB

Maximum SPL [1]

1000 Ω load, 1  kHz@ 3%THD

145.0 dB

Dynamic Range [1]

@ 1 kHz, 1000 Ω load

117.0 dB

Equivalent Output Noise [1]

typical, A-Weighted

28 dB

Power Requirements

+5 V DC (nominal), 10 V maximum (DC bias)


Positive pressure on diaphragm produces positive voltage on pin 3 with respect to pin 1


1.1 m (45 in.)



Net Weight

60 g (2.11 oz.)

[1] Measurements taken using RPM626 preamp set @ 0 dB using 8k bias resistor.

*All specifications measured with a 48 Vdc phantom power supply. The microphone operates at lower voltages, but with slightly decreased headroom and sensitivity.


Note: Testing is based on the use of supplied and recommended cable types. The use of other than shielded (screened) cable types may degrade EMC performance.

The CE Declaration of Conformity can be obtained from:

Authorized European representative:

Shure Europe GmbH

Headquarters Europe, Middle East & Africa

Department: EMEA Approval

Jakob-Dieffenbacher-Str. 12

75031 Eppingen, Germany

Phone: +49-7262-92 49 0

Fax: +49-7262-92 49 11 4