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Shure

Shure Beta 181

Ultra-compact side-address small-diaphragm electret condenser instrument mic: an XLR preamp with interchangeable cardioid, supercardioid, omni and bidirectional capsules

Type
Condenser (electret)
Pattern
Cardioid / supercardioid / omni / figure-8
Sensitivity
−46.5 dBV/Pa
Self-noise
20.5 dB(A)
Max SPL
149 dB SPL
Impedance
110 Ω
Rated range
20 – 20k Hz

Frequency response

Angle
Distance

Frequency response: from the spec sheet, p. 2. "Beta 181/C (Cardioid)", "Frequency Response"; relative dB. Distance, room and smoothing 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 spec sheet, p. 2. "Beta 181/C (Cardioid)", "Polar Pattern"; two circles (250 Hz to 1 kHz, 2500 Hz to 10 kHz), 0° at the bottom, 5 dB per ring. Distance not stated.

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All specs

From the user guide
Capsulesmall diaphragm, interchangeable capsules on a compact XLR preamp, locked by a knurled ring. General description and "Changing Capsules" (p. 5).p. 3
Sensitivity−46.5 dBV/Pa (4.7 mV/Pa), cardioid; open circuit voltage, 1 kHz, typical; also −49.5 dBV/Pa, supercardioid; also −52 dBV/Pa, omni; also −51 dBV/Pa, bidirectional. "–46.5 dBV/Pa (4.7 mV)", supercardioid "(3.4 mV)", omni "(2.5 mV)", bidirectional "(2.8 mV)". The 2015 sheet gives no sensitivity.p. 6
Self-noise20.5 dB(A), cardioid; equivalent SPL, A-weighted, typical; also 22.5 dB(A), supercardioid; also 23.5 dB(A), omni; also 23 dB(A), bidirectionalp. 7
Max SPL149 dB SPL, cardioid; 1 kHz, 1% THD, 1000 ohm load; also 151.5 dB SPL, cardioid, 2500 ohm load; also 152 dB SPL, supercardioid, 1000 ohm; also 154.5 dB SPL, supercardioid, 2500 ohm; also 154 dB SPL, omni, 1000 ohm; also 157 dB SPL, omni, 2500 ohm; also 153.5 dB SPL, bidirectional, 1000 ohm; also 156 dB SPL, bidirectional, 2500 ohm. THD of the preamplifier when fed the cartridge output at that SPL (footnote 2). Pages 6-7; the sheet gives the 1000 ohm figures.p. 6
Signal-to-noise ratio73.5 dB, cardioid; re 94 dB SPL, A-weighted; also 71.5 dB, supercardioid; also 70.5 dB, omni; also 71 dB, bidirectional. The 2015 sheet gives 72.5 dB for the supercardioid; 94 - 22.5 = 71.5, so the guide is right.p. 7
Dynamic range128.5 dB, cardioid; 1 kHz, 1000 ohm load; also 131 dB, cardioid, 2500 ohm; also 129.5 dB, supercardioid, 1000 ohm; also 132 dB, supercardioid, 2500 ohm; also 130.5 dB, omni, 1000 ohm; also 133.5 dB, omni, 2500 ohm; also 130.5 dB, bidirectional, 1000 ohm; also 133 dB, bidirectional, 2500 ohm
Output impedance110 ohm, output impedance. "110 Ω".p. 6
Rated load impedance1000 ohm, recommended minimum. "Shure recommends a minimum input load impedance of 1000 Ω."
Rated frequency range20 Hz to 20 kHz
Poweringphantom, 11-52 V DC (IEC-61938); best at 48 V. "11–52 V DC phantom power (IEC-61938)", p. 8; all specs measured at 48 V.p. 8
Current draw2.4 mA, maximum. "2.4 mA, maximum". The 2015 sheet says "1.2 mA".
Weight145 g. "145 g (5.1 oz.)".
Dimensions124.46 × 34.54 × 20.32 mm. Dimension drawing (Beta 181/C): length 124.46 mm (4.90 in.), capsule head 34.54 mm (1.36 in.), body 20.32 mm (0.80 in.) across.
Supplied accessoriesA57F stand adapter (mic clip); A181C carrying case (holds up to four capsules); A181WS foam windscreenp. 9
Clipping level10.5 dBV (2500 ohm load), 7.5 dBV (1000 ohm load), 1 kHz, 1% THDp. 7
Common mode rejection≥55 dB, 20 Hz to 20 kHzp. 8
PolarityPositive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3; sound from the back of the bidirectional capsule is out of polarity
Performance characteristicsTransformer output; no crossover distortionp. 3
GrilleHardened steel mesh
Replacement partsRPM181/C, RPM181/S, RPM181/O, RPM181/BI capsules; RPM181/PRE XLR preampp. 10
Optional accessoriesA75M universal mount; A53M isolation mount/swivel adapter; C25E cable
Rejection (Shure)Off-axis null at 180° (cardioid), 120° (supercardioid), 90° (bidirectional)p. 5
Applications (Shure)Cardioid: drum overheads, piano, acoustic instruments, M/S with a /BI; supercardioid: snare, close-miking; omni: room, string ensembles, mono overhead; bidirectional: Blumlein pair, mono overhead, between two sourcesp. 4
From the spec sheet
ConnectorXLR-3 male, on the preamp. "compact XLR preamplifier with integrated XLR connections".p. 1
ModelsBeta 181/C, /S, /O, /BI (each one capsule and one preamp); BETA181/KIT with all four capsules

Documents

Copies kept by Mic Archive, because manufacturers move and drop their documents. Each is © Shure, unchanged, with its original address.

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