SM 23

Common name: Neumann SM 23

Production Status: Discontinued / Vintage

The SM 23 is a special version of the SM 2 manufactured from 1961 to 1966. The major difference lays in the fact that the power supply is completely separated for the two microphone circuits. Using a special matching cable the microphone system can be powered through a completely separated PSU’s for redundancy. The SM 2 is the first microphone for coincidental stereo (X-Y, M-S, Blumlein) manufactured by Neumann from 1957 to 1966. It derives from the KM 56 and was in produced from 1957 to 1966. The 30 mm body houses two microphones inside with two Telefunken AC 701 k tubes, two output transformers and with all the other components. Two KK 56 capsules are installed inside the compact grille, one fixed and one turn-able. The SM 2 has remotely switchable polar pattern for ease of placement and use in auditorium recording applications. Omnidirectional, cardiod and bidirectional patterns are switchable separately for each microphone capsule. The sound performance is very close to the KM 56.  Microphone electronic circuit improvements during its production resulted in a SM 2b and SM 2c version.

Electrical Characteristics

Frequency Response
40Hz - 16 kHz
Output Sensitivity
1 mV/Pa
Max SPL
121
Max SPL, THD:
0.5
Self Noise (CCIR)
dB
Self Noise (DIN/IEC)
28 dB-A
Output Impedance
50 or 200Ω
Recommended Load
0.25 or 1kΩ
Powering
Proprietary unit
Supply Current
mA
Alternative Powering
Tube Model
Telefunken AC 701

Switchable Options

Pad
Filter/EQ

Physical Characteristics

Connector
Tuchel 3617 (12-pin)
Connector notes
Available Colours
Satin nickel
Weight
270 g
Length
210 mm
Min diameter width
Max diameter
30 mm
Depth

Accessories

Included
Optional
Z 10 adapter cable (from one 12-pole to two 8-pole connectors). Z 11 adapter cable (from one 12-pole to two 7-pole connectors). Z 42 elastic suspension. Z 43 windshield. SU 2t portable matrixing converter. NSMa23 dual power supply unit. Two NN 48b portable, NSK rack , N 52t studio plug-in or BB50 battery power supplies can also be used to power the SM 23..