Shure SM81

The Shure SM81 is a professional small-diaphragm condenser microphone with a cardioid polar pattern, specifically designed for accurate and natural recording of acoustic instruments. Thanks to its virtually flat frequency response, low self-noise, and high sound pressure handling, the SM81 has been a trusted choice for studio recordings, live performances, and broadcast applications for many years. Its detailed and balanced sound character really shines, especially with acoustic guitar, piano, percussion, and drum overheads.

Authentic sound reproduction with a wide frequency range
The Shure SM81 has a frequency range of 20 Hz to 20 kHz and is designed to capture the original sound of an instrument as faithfully as possible. The flat frequency response ensures a balanced reproduction of low, mid, and high frequencies, without overly emphasizing certain parts of the spectrum. This makes the microphone particularly well-suited for instruments where tonal detail, dynamics, and natural overtones are important. Think of the clear string sound of an acoustic guitar, the rich tone of a piano, or the subtle nuances of cymbals and other percussion instruments. The SM81 features a cardioid polar pattern. This allows it to pick up sound primarily from the front, while suppressing sound from the rear. Furthermore, the polar pattern remains consistent across a wide frequency range, so that sound entering from off-axis experiences relatively little coloration. This helps minimize unwanted crosstalk and ensures a controlled recording, both in the studio and on stage.

Adjustable low-cut filter for optimal control over low frequencies
A key feature of the Shure SM81 is its built-in, three-position adjustable low-cut filter. This allows the microphone to be tailored to the sound source and acoustic conditions. The first setting provides a flat frequency response, preserving the full low-end. The second setting activates a gradual roll-off of 6 dB per octave. The third setting provides a steeper roll-off of 18 dB per octave, which allows for more effective suppression of unwanted low frequencies. These settings are particularly useful when miking acoustic instruments. For example, the filter can help reduce contact noises, stage vibrations, and low-frequency ambient noise. It can also compensate for the proximity effect: the natural amplification of low frequencies that occurs when a cardioid microphone is placed close to a sound source.

High Sound Pressure Level Handling with Switchable -10 dB Pad
In addition to accurately reproducing subtle instrumental details, the Shure SM81 can also handle high sound pressure levels. The microphone features a built-in, switchable 10 dB pad, which attenuates the input signal internally. With a load of 1 kOhm, the maximum sound pressure level is 136 dB SPL without the pad engaged. With the -10 dB pad engaged, this can increase to approximately 146 dB SPL. This makes the SM81 suitable for louder sound sources, such as drum overheads, powerful percussion, and instruments recorded at close range. The attenuation switch can be locked in place using the included locking mechanism. This prevents the setting from changing unintentionally during a recording or performance.

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Low self-noise and professional signal quality
With aself-noise level of just 16 dB(A) and a signal-to-noise ratio of 78 dB, the SM81 delivers a clean signal, even when recording quieter passages. The microphone combines these features with a sensitivity of -45 dBV/Pa (5.6 mV/Pa) and a balanced XLR output. Its low susceptibility to radio-frequency interference helps minimize unwanted interference. In addition, the microphone is designed to maintain low distortion across a range of load impedances. The SM81 operates on phantom power and can be connected to professional mixing consoles, microphone preamps, and audio interfaces with a suitable XLR microphone input. Shure recommends 48V phantom power for optimal performance, although the microphone also operates with a supply voltage of 11 to 52V DC. At lower supply voltages, sensitivity and available headroom may decrease slightly.

Suitable for studio, stage, and broadcast
The Shure SM81 is designed for a wide range of professional recording and amplification applications where accurate sound capture is essential. For acoustic guitar, the microphone provides a detailed capture of string attack, resonance, and overtones. For piano recordings, the wide frequency response allows for the capture of both the low registers and the bright overtones. For drums, the SM81 can be used as an overhead microphone, where its natural reproduction of cymbals and high sound pressure level handling are key advantages. The SM81 is also a suitable choice for string instruments, acoustic ensembles, and percussion. Thanks to its consistent cardioid polar pattern, the microphone can also be used effectively in situations where multiple instruments are being recorded or amplified simultaneously. The SM81 is not intended exclusively for studio recordings. Its rugged construction, controlled directional response, and low susceptibility to interference also make it suitable for live sound and professional broadcast productions.

Robust Steel Housing and Reliable Construction
The Shure SM81 features a sturdy steel housing with a metallic vinyl coating and stainless steel protective grilles. The construction is designed for intensive professional use and continues to function under a wide range of conditions. The microphone is suitable for use at temperatures ranging from approximately -7 °C to 49 °C and relative humidity up to 95%. This makes it suitable for outdoor productions as well, provided it is adequately protected from direct precipitation and other harmful influences. Measuring 21.2 cm in length, 23.5 mm in diameter, and weighing 230 grams, the SM81 features a slim, cylindrical body. This allows the microphone to be precisely positioned near instruments and in microphone setups with limited space.

Included Accessories
The Shure SM81-LC comes with an A57F microphone clip for mounting on a stand, a foam windscreen, a lock for the -10 dB attenuation switch, and a zippered carrying pouch. The windscreen helps reduce wind noise and airflow, while the storage pouch provides protection during storage and transport. Optional accessories are also available for specific applications, including the Shure A81WS large windscreen, the A81G grille with wind protection, the A27M stereo microphone adapter, and a shock mount for additional isolation from mechanical vibrations.

Shure SM81 features:

• professional small-diaphragm condenser microphone for instruments
• suitable for acoustic guitar, piano, string instruments, percussion, and drum overheads
• Applications: studio recording, live sound, and broadcast
• Model: SM81-LC
• Microphone type: electret condenser
• polar pattern: cardioid
• Frequency range: 20 Hz – 20 kHz
• Virtually flat frequency response for accurate sound reproduction
• Consistent directional pattern with minimal coloration off-axis
• Adjustable low-cut filter with three settings
• Low-cut settings: flat, 6 dB/oct, and 18 dB/oct
• Switchable attenuation: 0 dB / -10 dB
• lockable attenuation switch
• Maximum sound pressure level: 136 dB SPL at 1 kOhm load, without attenuation
• Maximum sound pressure level with -10 dB pad: 146 dB SPL at 1 kOhm load
• Self-noise: 16 dB(A)
• Signal-to-noise ratio: 78 dB at 94 dB SPL
• Sensitivity: -45 dBV/Pa (5.6 mV/Pa) at 1 kHz
• Nominal output impedance: 150 ohms
• Recommended minimum load impedance: 800 ohms
• Balanced 3-pin XLR output (male)
• Power supply: 11 to 52 V DC phantom power
• Recommended power supply: 48 V phantom power
• Low susceptibility to radio frequency interference
• Steel housing with metallic vinyl coating
• Stainless steel protective grilles
• Dimensions: 21.2 cm long, 23.5 mm in diameter
• Weight: 230 grams
  
  

Included: Shure A57F microphone clip, foam windscreen (49A111), -10 dB pad lock (34A830), and zippered carrying case (95A2313)

Optional accessories: A81WS windscreen, A81G grille, A27M stereo adapter, and compatible shock mounts