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Neumann

Neumann KM 131

Small-diaphragm condenser, omni (free-field equalised pressure capsule): the AK 31 active capsule on the KM 100 output stage; discontinued

Type
Condenser
Pattern
Omni
Sensitivity
−38.4 dBV/Pa
Self-noise
16 dB(A)
Max SPL
140 dB SPL
Impedance
50 Ω
Rated range
20 – 20k Hz

Frequency response

Angle
Distance

Frequency response: from the manual, p. 7. Free field, IEC 60268-4 ("gemessen im freien Schallfeld nach IEC 60268-4 / measured in free-field conditions", printed under the first graph of the page; the 2012 brochure adds "tolerance ± 2 dB"). Distance not stated.

Dashed: outside the rated range, or simulated (other angles and distances). Hover or tap the graphs for values.

Polar pattern

Polar pattern: from the manual, p. 7. Free field (as the response). Each curve is drawn on one side only (125 Hz to 1 kHz left, 2 to 16 kHz right); the pattern is taken as symmetric.

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All specs

From the manual
CapsuleAK 31 active capsule: free-field equalised pressure transducer (the impedance converter sits in the capsule housing). "AK 31 is a free-field equalized pressure transducer. The sensitivity in the free sound field is flat up to 20 kHz. In the diffuse sound field there is a roll-off above 5 kHz."p. 3
Sensitivity−38.4 dBV/Pa (12 mV/Pa), 1 kHz into 1 kohm rated load. Stated as 12 mV/Pa; converted: 20·log10(0.012) = -38.4. The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).p. 5
Self-noise16 dB(A), IEC 60268-1, A-weighting IEC 61672-1, RMS. "16 dB-A". The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).
Self-noise (CCIR 468)25 dB, CCIR 468-3, quasi peak. The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).
Max SPL140 dB SPL, less than 0.5% THD; also 150 dB SPL, with preattenuation. "THD of microphone amplifier at an input voltage equivalent to the capsule output at the specified SPL." The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).
Signal-to-noise ratio78 dB, re 94 dB SPL, A-weighted; also 69 dB, re 94 dB SPL, CCIR 468-3. The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).
Dynamic range124 dB, microphone amplifier, A-weighted. The table on p. 5 lists KM 120, 130, 131, 143, 140, 145 and 150; this is the KM 131 column (the 2012 brochure, p. 11, gives the same).
Output impedance50 ohm, rated impedance
Rated frequency range20 Hz to 20 kHz. The 2012 brochure (p. 10) adds "measured in free-field conditions (IEC 60268-4), tolerance ± 2 dB" for the graphs.
Current draw2 mA
Pad−10 dB. Recessed slide switch on the KM 100 output stage; "Attenuation is achieved by reducing the capsule voltage to one third of nominal."p. 4
ConnectorXLR-3 male. On the KM 100 output stage; matching connector XLR3F (brochure p. 11).p. 2
Weight80 gp. 5
Dimensions22 × 92 mm. "92 x 22 mm" (L x ø): diameter × length, capsule on the output stage. The active capsule alone is about 35 mm long (p. 2).
Finishmatt black. "blk" for the AK 31 and the KM 100 output stage.p. 3
BuildTwo parts that unscrew: the AK 31 active capsule (Cat. No. 69002) and the KM 100 output stage (Cat. No. 07395); the capsule can be used up to 50 m from the output stage on a 3 mm cable (LC 3 KA)p. 2
Polarity (manual)Pin 2 hot in the pin table (p. 2); the note on unbalanced operation (p. 4) says pin 3 is hot with the KM 100 output stage
From the catalog
Rated load impedance1000 ohm, rated load impedancep. 11
Poweringphantom P48, 48 V ± 4 V (IEC 61938). The manual (p. 5) gives P48, IEC 61938, without the tolerance.
Max. output voltage10 dBu
SBK 130 A sphereOptional sound diffraction sphere (Cat. No. 008612) that slips over the KM 130/KM 131: up to 2.5 dB lift between 2 and 10 kHz from the front, up to 2.5 dB cut above 5 kHz from the rear; 40 mm diameter, about 30 gp. 4
Use (Neumann)Close miking of instruments where extraneous sound needn't be rejected, in a balanced acoustic: acoustic guitar, wind, strings, percussion, drums; spot micp. 9

Documents

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