Shure SM81

Shure SM microphone models stringent and high-tech . These so-called “legendary” microphones have endured decades of rigorous use by audio professionals in various fields: audio engineering, sound reinforcement, music production, broadcasting, etc.

The Shure SM81 is no exception since this high-end condenser microphone benefits from a perfectly robust design to better respond to outdoor use in varied temperature and humidity conditions.

This studio microphone with cardioid polar pattern also offers perfect off-axis sound rejection and its response curve is sufficiently flat to reproduce the sound faithfully, precisely, accurately and correctly. Its low noise level and relatively low mic sensitivity to interference make it a perfect transducer for stage applications and recording studio uses.

So is the Shure SM81 really a wise microphone purchase for your home studio and sound reinforcement project ? Below, our complete test and review to judge the full potential of this pro electrostatic microphone!

Shure SM81 Microphone Overview

Quite stylish in vintage appearance, the Shure SM81 has a beautiful design and its finish is subtly neat . On the front of the microphone, we find the Shure brand logo below which is indicated the Shure SM81 model and the type of microphone, which in the case of the SM81 works with a condenser.

Below these inscriptions, we also access a switch (or switch) which allows low-cut filtering to be carried out in three positions: neutral , at -6 dB/octave or at -18 dB/octave . The Shure SM81 also has a -10 dB . This metallic gray stereo and electret microphone also has fairly compact dimensions of 30.23 x 15.49 x 7.62 cm .

Its fairly long shape, not very thick and more or less wide, adapts to all hand shapes. This professional microphone can be held by a left-handed person as well as by a right-handed person. Its low weight of around 240 g also makes it much more ergonomic for use both on its microphone stand and held by hand. On stage, the Shure SM81 therefore remains as practical and efficient to use as any type of lavalier microphone, wireless lavalier microphone and gooseneck microphone.

With a very low noise level , the Shure SM81 remains very insensitive to handling noise. This is what makes it very effective and practical to use on stage . The Shure SM81 allows you to record voice, whether singing or speaking: speeches, voice-overs, podcasts, etc. This condenser and electret studio microphone also provides a wide frequency response . This allows the sound to be reproduced as faithfully as possible.

In pre-production, the sound is already refined, the audio quality of the voice recording or that of the sound recording of acoustic instruments will be optimized after the final audio processing. This sound quality can be further refined, and improved when playing the sound recorded in waw (uncompressed) or mp3 (compressed) format on your computer, on your Smartphone or on your tablet using the equalizer of a Dap or (Digital audio player such as VLC or iTunes among many others).

The Shure SM81 has also been designed to meet various recording needs for acoustic instruments such as acoustic guitar, grand piano and cymbals. On the other hand, for the audio recording of percussion and guitar amps, it is recommended to choose a dynamic moving coil microphone or a or Rode NT USB type microphone

If you want to find a better alternative to the Shure SM81 to better save money, we advise you to opt for a large diaphragm condenser microphone from Neumann, Sennheiser or SE Electronics.

The Shure SM81 comes with a number of accessories including:

• An A57F microphone clip
• A windscreen 49A111
• A 10 dB 34A830 attenuator lock
• A transport and storage case 95A2313

Other optional accessories are available to take full advantage of the sound quality and audio performance of the Shure SM81 microphone:

• A81G noise filter grille
• Reinforced shock protection for microphones with conical bodies (half-rack version) A55HM
• Reinforced windscreen SM81 A81WS
• A27M Stereo Microphone Adapter
• Microphone tripod stand (4.3 m) S15A
• TRIPLE-FLEX 25 cable, C25F chrome XLR connectors

Note that Shure also provides a set of replacement R104 capsules and grilles .

Shure SM81: a microphone designed for audio professionals?

The Shure SM81 perfectly meets the needs of musicians, singers, presenters and studio professionals looking for a high-performance microphone . Thus, the Shure SM81 remains ideal for sound recording on stage and in home studios.

This professional condenser microphone also has a uniform response curve (and therefore relatively flat) allowing precise reproduction of the sound source captured, whether it is a voice or the sound of an acoustic instrument, particularly the guitar. , piano and cymbals.

The pro microphone is equipped with a low-cut filter that can be switched to three setting choices, allowing the sound to be purified as best as possible in the bass. The Shure SM81 professional microphone even has a -10 dB attenuator pad that can be locked to allow voice pickup and sound pickup that is flexible, balanced and refined.

Its cardioid polar pattern also allows this high-end stereo condenser microphone to isolate the sound source as well as possible and eliminate background noise. The Shure SM81 remains suitable to meet the needs of audio professionals as this condenser microphone:

• Offers a uniform response curve of the audio bandwidth for optimal accurate and correct reproduction of the sound source thus captured. The frequency response is between 20 Hz and 20 kHz .
• Generates very low self-noise while its output level is relatively high.
• Remains very little affected by varying load impedances.
• Provides a cardioid polar pattern with a uniform frequency and a symmetrical axis, for maximum rejection of off-axis sounds. The Shure SM81 therefore remains as efficient as a shotgun microphone insofar as it displays a clearly pronounced directionality in its axis. This above all allows precise, optimal and long-range audio capture, even in the middle of several noisy sound sources. This specific characteristic gives this microphone the great capacity to amplify the sound dynamics of recordings naturally, whether on stage or in a studio.
• Remains very insensitive to radio wave interference (unlike most condenser microphones).
• Features a switchable low cut filter with three positions: neutral , -6 dB/octave or -18 dB/octave for maximum pre-filtering of the sound signal to be recorded and processed.
• lockable -10 dB attenuator to better clean the sound to be recorded, broadcast or processed.
• Operates using phantom power ( DIN 45 596 voltage of 12 V or 48V ) for optimal conversion of the sound signal into an electrical signal without generating any loss, drop or distortion.
• Benefits from a robust steel construction, a guarantee of durability, but above all to allow outdoor use in very varied temperature and humidity conditions.

By the way, you can also check out our test guide and review on the t.bone RB 500 ribbon microphone . This guide shows you the presentation of the bidirectional directivity of this microphone, its multiple applications, its sound quality, technical characteristics, and without forgetting our opinion on the microphone.

Shure SM81: a legendary microphone with a robust design

Let us first note that Shure SM81 is an electret condenser microphone just like the Sony C100 microphone . Robust in design, this singing and karaoke microphone can operate in a wide range of temperature and humidity conditions . The Shure SM81 benefits from a fairly durable steel construction with a metallic and vinyl paint finish.

Its head is protected by stainless steel grilles. Although everything has already been thought of to provide the Shure SM81 with optimal protection (windscreen, armored carrying case, etc.), the manufacturer has still taken care to reinforce the solidity of the Shure SM81.

Thus, this electret condenser microphone is capable of operating in fairly extreme operating temperature conditions of -6.7° to 49°C . Note also that the Shure SM81 can be stored safely, without risk of damage, in its reinforced protective case at a storage temperature of between -29° and 74°C .

All in a relative humidity condition of 0 to 95% . You will only need to ensure that the Shure SM81 operates with 48Vdc ( IEC-61938 ) in order to maintain its durability.

Shure SM81: optimal, unidirectional sound capture

The Shure SM81 displays a cardioid polar pattern . This unidirectional directivity provides optimal audio capture when the audio source is placed at 0°, that is to say facing the microphone. This cardioid microphone isolates the voice or sound of a captured instrument from other audio sources and also from surrounding noise.

Due to its rather particular characteristic which only captures a single sound source, the Shure SM81 also helps to make the most of the proximity effect. Thus, this cardioid microphone gradually increases low frequencies by 6 to 10 dB below 100 Hz when the studio microphone is placed less than a centimeter from the audio source ( 6 mm to be more exact).

This phenomenon, which is commonly referred to as the “proximity effect”, makes it possible to give more roundness and warmth to sounds and voices in the bass. The distance of the Shure SM81 microphone to less than 10 centimeters from the sound source also makes it possible to enhance the effect of the captured voice or that of the sound of a natural acoustic instrument.

This cardioid condenser microphone for recording vocals in the studio and on stage remains as efficient as a dynamic moving coil microphone (like the Sennheiser E835 for example) thanks to its symmetrical XLR connectivity eliminating any ground loop effect. .

Aside from its qualities and specificities meeting the requirements of audio professionals, this cardioid condenser microphone differs from bidirectional and omnidirectional microphones. Bidirectional mics pick up sounds from two sound sources in two different directions.

Although these microphones isolate voices and sounds as best as possible, the capture remains distributed and focused in two angles. Which is not the case with a high-performance unidirectional microphone like the Shure SM81. The same applies to a dynamic, or even electrostatic, microphone with omnidirectional directivity.

All microphones offering this directionality (i.e. any type of omnidirectional mic or surround mic) pick up sound evenly in all directions, but in a consistent manner. These types of microphones do not isolate and define the voice well.

Omnidirectional mics are best suited for vocal pickup of a group singing or audio pickup of a small philharmonic group. The Shure SM81 for its part is the perfect choice of microphone for a solo singer , a guitarist or a pianist who plays and/or sings solo.

A flat response curve for accurate and precise audio reproduction

The Shure SM81 offers a wide frequency response with very low background noise thanks to its polar pattern (or polar pattern) with cardioid directivity. This unidirectional vocal microphone features a flat response curve , low self-noise and a high output clipping level.

The Shure SM81 imparts very low distortion over a range of load impedances. It also remains very insensitive to RF. Its wide frequency response makes the Shure SM81 quite sensitive to wind, hiss and drafts caused by indoor ventilation, air conditioning and air conditioning systems. And likewise, we should avoid placing this microphone near most common household appliances (microwave oven and other kitchen appliances).

It is also necessary to wear the foam windscreen provided. This will reduce the effects of noise caused by outside wind, but also eliminate sibilants and plosives when speaking, singing or playing an acoustic instrument while singing or singing. speaking in front of the Shure SM81.

To fine-tune the setting, we will configure the low-cut filter by opting for one of the three adjustment modes accessible from this microphone. It can be used in particular to reduce parasitic noise in low frequencies and avoid saturation in bass sounds.

The A81G pop filter grille (optional) helps to attenuate breath noise , sibilants and plosives (when the microphone is placed near the mouth for example). We can further optimize the use of the Shure SM81 microphone outdoors by opting for the large A81WS foam windscreen (also supplied as an option).

Zoom on the sound quality of the Shure SM81 microphone

The Shure SM81 is a condenser-type microphone with a frequency response of 20 Hz to 20 kHz . The Shure SM81 displays a cardioid or unidirectional polar pattern with 6 dB 15 dB of backward cancellation . The (advertised) output impedance rating for the Shure SM81 microphone is 150 Watts for connection to microphone inputs of 150 Ohms or greater on audio amplifiers and preamplifiers.

In open circuit, this studio microphone displays a voltage of -65 dB (0.56 mV) ( 0 dB = 1 Volt per microbar ). The Shure SM81 microphone features a three-position low-cut filter selector as well as a lockable 10 dB attenuator switchable between " 0 " and " -10 ".

A Shure SM81 type microphone is capable of receiving duplex phantom power with an output between 11 and 52 Volts DC or through an audio mixer, an audio mixing console, an audio equalizer or an audio interface capable of providing a phantom power voltage of between 11 and 52 Volts DC

The Shure SM81 is an electret condenser microphone. This means that unlike a dynamic microphone, it requires phantom power to operate. This will feed the sound dynamics of the audio signal which will emerge in the form of an electrical signal. A Shure SM81 type microphone requires duplex phantom power .

Such a power source can be supplied to this type of microphone via the microphone input (provided with LEDs and 48 Volt phantom power switch) of a preamplifier (or other amplifiers), a vocal equalizer , audio mixer, mixer or mixing console.

Otherwise, you will absolutely have to use an external power source of the PS1A type dedicated to the Shure SM81. Duplex phantom power sources provide a voltage between 11 and 52 Volts.

To avoid any risk of intermittent short circuits between broken shielding cables and symmetrical conductors, take great care to only use high quality cables. We will also avoid causing the ground loop effect by taking care to keep the Shure SM81 microphone away from other metal objects.

The recommended grounding technique remains similar to that used for audio devices. If we want to optimize the sound quality of audio signals with as little distortion as possible, we must use a load impedance greater than or equal to 800 Watts for this type of microphone.

Note, however, that the Shure SM81 is actually usable with a minimum load impedance of 150 W , but this reduction will result in a significant drop in the output clipping threshold. However, the power supply itself can add a greater or lesser load to the microphones.

The Shure SM81 is equipped with a low-cut filter adjustable to three positions. The selector is integrated into the body of the microphone, but slightly recessed to avoid involuntary operation which could cause annoying handling noise.

We can thus choose between a flat response, a low frequency attenuation of 6 dB per octave below 100 Hz or a reduction of 18 dB per octave in the bass below 80 Hz . A uniform response, i.e. a flat setting, will produce a more natural sound reproduction.

A low frequency cutoff reduces 18 dB per octave below 80 Hz and helps eliminate floor vibrations and bass sounds such as the whir of a fan, air conditioner or air conditioning system. We can even make this adjustment to compensate for proximity effect saturation or to attenuate bass which may prove too heavy and dull.

Then, you can always readjust the microphone volume gradually via the interface of a preamp, a mixing table or an external audio equalizer equipped with an output for audio monitoring headphones.

When the Shure SM81 is set to attenuate low frequencies below 100 Hz by 6 dB per octave . This will have the effect of compensating for the proximity effect or attenuating the bass which could weigh down or dull the sound.

When the Shure SM81 is placed close to a singer or an acoustic instrument, it generates a beautiful proximity effect which helps beautify the sound in the Bass . Let us just note that the low cut filter always remains useful to avoid any saturation due to a possible overload of sound frequency in the capture of a tone located at the bottom of the audio spectrum.

Aside from the low cut filtering switchable in three positions, the Shure SM81 also has a lockable attenuator from 0 to -10 dB . This switch prevents excessively high sound pressure levels (SPL) from overloading the internal electronic components of the Shure SM81.

Adjusted and locked to the " +10 " position, the Shure SM81's built-in attenuator reduces microphone output by 10 dB while increasing the maximum sound pressure level before clipping by 10 dB . The attenuator ring can thus be locked in position “0” or position “-10”.

The output gain of the Shure SM81 exceeds output gain of most dynamic microphones approximately 15 dB At moderately high SPL levels, this relatively large output power might require attenuation to enable optimal audio balancing at the signal output.

If the preamp, amplifier, audio mixer, vocal equalizer or mixing desk does not have an attenuator, a resistance attenuator can be inserted between the microphone and the input of the audio interface used.

The Shure A15AS attenuator 15 , 20 or 25 dB ) has been specially designed to work with Shure SM series condenser and condenser microphones.

Regarding the dynamic description of the Shure SM81 (that is to say the dynamic characteristics of this professional microphone), note that its condenser capsule is followed by a captive attenuator device (unlike integrated capsules to other large diaphragm condenser microphones).

This attenuator is controlled by a selector which allows you to set an attenuation of 10 dB at the microphone output. The sound signal is first transmitted to an impedance converter with field effect transistors (Fet: Field effect transistor).

At its output, this field effect transistor ( Fet ) engages an active low-cut filter which is controlled by a selector according to three adjustment modes. The filter output is combined with a transformer to provide a balanced output to the noise filter .

An active DC power supply circuit regulates the voltage of the phantom power supply to operate the Shure SM81 over a very wide voltage range. A protection against polarity inversions helps to alleviate problems caused by poor wiring.

The technical characteristics of the Shure SM81 microphone

• Type: condenser microphone (electret polarization)
• Brand: Shure
• Model: Shure SM81
• Frequency response: 20 Hz to 20 kHz
• Directivity curve: cardio polar diagram (unidirectional) – uniform in frequency, symmetrical about the axis.
• Output impedance: Nominal value: 150 Ohms ( 85 W real) / Minimum recommended load impedance: 800 Watts (possible use with loads of a minimum of 150 Watts with reduced clipping threshold)
• Output configuration and connector: balanced output via transformer; XLR type male connector
• Output level (at 1000 Hz): Open circuit voltage: -45 dBV/Pascal ( 5.6 mV ) (1 Pascal = 94 dB SPL ); -65 dBV/mbar ( 0.56 mV ) (1mbar = 74 dB SPL )
• Clipping level (at 1000 Hz): On 800 W load: -4 dBV (0.63 V) / On 150 W load: -15 dBV (0.18 V)
• Total harmonic distortion: Less than 0.5% ( 131 dB SPL at 250 Hz on 800 W )
• Maximum SPL level (at 1000 Hz): On 800 W load: 136 dB (attenuator at 0) 146 dB (attenuator at –10) / On 150 W load: 128 dB (attenuator at 0) 138 dB (attenuator at –10)
• Hum pickup: -3 dB SPL equivalent in a 1 mOe field (60 Hz)
• Self-noise: 16 dB typical , A-weighted / 19 dB typical , weighted according to DIN 45 405
• Signal-to-noise ratio: 78 dB (IEC 651)* at 94 dB SPL
• Overvoltage and phase inversion protection: External voltage max. applied to pins 2 and 3 relative to pin 1: +52 V DC . / Protection against reverse polarity: 200 mA max .
• Capsule capacity: 54 pF
• Low cut filter selector positions: Flat response, –6 dB/octave below 100 Hz , -18 dB/octave below 80 Hz
• Attenuation selector positions (lockable): 0 or –10 dB
• Power supply: Supply voltage: 11 to 52 V DC , positive pins 2 and 3 / Current consumption: 1.2 mA max .
• Environment: Storage temperature: – 29° to 74° C ( –20° to 165° F ) / For use temperature: – 6.7° to 49° C ( 20° to 120° F )
• Body: Steel construction with vinyl metallic paint finish and stainless steel grill
• Dimensions: 30.23 x 15.49 x 7.62 cm
• Net weight: 230g

Our opinion on the Shure SM81 microphone

Buying one or more Shure SM81 condenser microphones at the best value for money remains ideal for optimizing the audio quality of vocal and instrumental recordings in the studio and home studio. But beyond this framework, the Shure SM81 remains perfect for recording vocals and miking acoustic instruments on stage.

This studio microphone benefits from a robust steel construction and has a stainless steel metal grille. The microphone has been designed to be able to withstand fairly harsh temperature conditions of -29° to 74°C (if the Shure SM81 is stored in its armored case) and -6.7° to 49°C when counting the 'to use.

The Shure SM81 is one of the few condenser and condenser microphones capable of withstanding such temperature conditions. From a purely functional point of view, everything has been designed to allow this microphone to broadcast and record sound in the most precise, detailed and correct way possible: flat response curve for faithful and optimal sound reproduction, cardio directivity high-tech for optimal rejection of off-axis sounds, low noise level and high output clipping level…

Add to this the possibility of switching the low cut filtering according to three adjustment modes and the fact of being able to preset the attenuator by locking the corresponding switch (either at zero or -10 dB) directly from the Shure SM81 microphone.

Its very low sensitivity to parasitic noise in the high frequencies makes it a perfect choice of microphone for stage and home studio applications including the miking of acoustic instruments such as the acoustic guitar, the grand piano and cymbals in particular. . Operating under duplex phantom power, the Shure SM81 generates approximately 15 dB of additional gain over conventional dynamic and moving coil microphones.

For anyone who wishes to acquire one or more studio microphones to complete their audio recording and sound equipment, we can only recommend the purchase of one or more condenser microphones at the best quality/price ratio. type Shure SM81.

Shure SM81 Demo

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