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Which microphone for guitar recording?

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Are you looking for a high-performance microphone dedicated to recording an instrument such as an acoustic guitar or an electric guitar? Be aware that there are three types of microphones for guitar recording including condenser mics, dynamic mics and ribbon mics. This guide can help you choose the right mic for guitar recording. We have selected for you the best dedicated microphones for guitar sound recording.

Which microphone for guitar recording?

🎤 by Kevin Jung

Summary of the article 👇

Recording an acoustic guitar at home or in the studio requires the use of a microphone separate from the instrument . This principle applies both to a folk guitar like the Taylor GS Mini Mahogany and a classical guitar like the Yamaha C40II.

The harmonic subtlety of an acoustic guitar cannot, however, be captured with any microphone. You must choose a microphone adapted to the needs of a guitar recording, and several parameters must be considered in this process. Discover in this guide the best microphone for guitar recording.

How to choose the microphone according to the sound reproduction technology?

There are three types of microphones for guitar recording . These are condenser microphones or condenser microphones , dynamic microphones and ribbon microphones. These three types of microphones differ in the way they convert the mechanical energy of sound into an electrical signal.

Dynamic transducer microphones

Dynamic transducer mics work like speakers, but in reverse. This is due to the components behind the sound reproduction for this type of microphone. It consists of a magnet , a diaphragm and a voice coil . The coil is attached to the back of the diaphragm.

The voice coil and magnet combine to create a magnetic field. The sound waves strike the diaphragm to make it vibrate. The vibration generated is transmitted to the voice coil. The latter then begins to vibrate on the magnet to create a voltage by induction. The applied voltage changes in step with the vibrations of the membrane to define the electrical signal . This phenomenon is also known as electromagnetism .

The dynamic microphone is often used live as a handheld microphone . It is also very popular with guitarists for home studio or recording studio recording. It must be said that this dynamic microphone is as versatile as the condenser microphone in its uses. It is suitable for picking up bass drums or other instruments with high sound pressure.

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Dynamic microphones are primarily appreciated for their robustness . They can continue to function well even after suffering several drops. This type of microphone is also more weather resistant compared to a condenser microphone. It can therefore be used as a studio microphone , but also as an outdoor microphone .

There are also no moving parts in the design of dynamic microphones. These can thus support different recordings at high volumes while remaining faithful to the sound sources. It is also for this particular reason that a dynamic transducer studio microphone is the most common choice of microphone for guitar recording.

Guitar recording involves the microphone being placed in front of the amplifier that the guitar is plugged into. The volume generated by this amplifier is quite high. The guitar's harmonics may be lost if the microphone cannot record at such a volume.

The best dynamic microphone for guitar recording: AKG P5S

A dynamic microphone is not the first choice for recording a classical guitar like the Yamaha Etude C40 A 4/4 . The AKG P5S may, however, be an exception to this rule given the simplicity it provides for guitar recording. Its technology is conducive to eliminating ambient noise to ensure a clean recording.

The AKG P5S also offers a very wide frequency response from 40 Hz to 20 kHz . You can capture all the harmonic subtleties of an acoustic guitar with this microphone. However, this performance is offered at a more affordable price than that of a condenser microphone.

Condenser microphones

A condenser microphone uses a component called a capacitor to store electrical energy between two plates in an electric field. One of these plates has a positive charge while the other has a negative charge . Creating the initial electric field between the two plates requires a source of electricity. The condenser studio microphone notably obtains the electrical current it needs to operate in the form of phantom power .

Condenser microphones
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Phantom power is a DC voltage of approximately 48 V that must be supplied to the microphone to operate it. It is traditionally delivered to the microphone using a preamplifier or mixing board. This DC voltage is often obtained today with an audio interface or an external sound card.

The lightweight plate on the front of a conventional condenser or condenser microphone vibrates when a sound wave hits it. The distance between the two plates changes depending on these vibrations. This change affects the amount of electrical energy stored between the two plates.

The conserved electrical energy increases as the plates get closer together and decreases as they move further apart. An overload can occur when this energy is not well controlled. This is why most condenser microphones come with a switchable attenuator for the bass. This function is supplemented in many cases by attenuation buffers.

Sensor size of condenser microphones

Condenser microphones can be equipped with small or large . What these two types of capsules have in common is their concept. They consist of a metal plate with a parallel arrangement to a very thin plastic diaphragm.

A microscopic-sized metallic layer covers the surface of the diaphragm. The capsule is also so as to leave space for the passage of air between the plate and the diaphragm . This replicates the effect of a capacitor when bias voltage is applied.

The space left for the passage of air changes as the sound waves move along the diaphragm. The capacitance varies accordingly to alternate the bias voltage . A built-in preamp receives the signal to increase the output level and adjust the impedance. This pre-amp can be designed as a valve or transistor model.

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Sensitivity is the strong point of condenser microphones. Their range of frequency responses is more complete than that of dynamic mics . They are also faster in transient response. These microphones thus prove to be more efficient in capturing harmonics , but also the lowest bass . It is easy to achieve natural and realistic sound with such mics.

The problem with condenser mics is that they are quite fragile and can be expensive to repair. The more affordable models also tend to have abnormal treble brightness. It is also recommended to use a suspension bracket with this type of microphone to reduce rumble during recordings. This provision is all the more necessary if your recording studio is installed in an area close to road traffic.

A condenser microphone with a small capsule is the best option if you are aiming for high-fidelity reproduction of sound . Large capsule models have the characteristics of a dynamic instrument in themselves. This means they can add more elements unique to their sonic characteristics to the recording. They also appear warmer in the midrange and more complete in both low and high frequencies.

Impedance conversion technology

Condenser microphones can use two technologies in particular in impedance conversion for signal output. These are vacuum tubes on the one hand and field effect transistors or FETs on the other hand. These conversion modules can also act as amplifiers in the operation of active microphones.

A microphone with vacuum tubes like the Telefunken TF-47 needs to be connected to an external power supply to work. They have more self-noise and produce a very warm with typical tube saturation and quality attenuation. The microphone output is always coupled to a transformer . Tube technology, however, increases the fragility of the microphone.

FET microphones, on the other hand, operate from phantom power or DC bias voltage . They have less self-noise and produce a fairly cold, but more precise sound. This is also why they are often described as high-fidelity microphones or HF microphones. An HF microphone with FET technology can sometimes have a transformer coupled to its output. It nevertheless has the advantage of being more robust and durable than a tube microphone.

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The best condenser microphones for recording guitar: Shure SM81

The Shure SM81 is a condenser microphone designed specifically for recording acoustic guitar. This includes a classical guitar like the YAMAHA ETUDE CS40 3/4 or an acoustic guitar like the Harley Benton CLP-15E Java Exotic. The Shure SM81 is also as robust as it is efficient, although its slim silhouette might suggest the opposite.

It is constructed of durable vinyl coated steel for optimal operation in varying humidity and temperature conditions. The frequency response is very flat, which results in good reproduction of the sound source . The Shure SM81 also has low self-noise and provides minimal coloration to the audio signal even when moving off-axis.

Ribbon microphones

The ribbon microphone was the first form of high-quality microphone to be used for music recording. They began to be used in the Jazz Age and gained popularity in the 1950s and 1960s with rock 'n' roll. They then became obsolete in the 1970s, but have regained popularity in recent decades.

The operation of ribbon microphones is very similar to that of dynamic microphones . The difference is that the voice coil and the diaphragm are replaced by a metal ribbon with a wavy and very thin shape. The latter is suspended in a magnetic field. The ribbon moves according to the sound waves that hit it. An alternating current is generated accordingly according to the principle of electromagnetism.

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The ribbon inside the microphone has the advantage of being light and moving with great freedom. There is therefore no real obstacle from a physical point of view to the response provided by the microphone. This results in a smooth, natural sound when recording with a ribbon microphone .

It should be noted, however, that ribbon microphones are more delicate than dynamic microphones. The passage of wind can damage them in the same way as high volumes. The output level of a ribbon microphone also tends to be very low.

It is therefore necessary to high gain, low noise mic preamp An exception is nevertheless allowed for active ribbon microphones which operate with phantom power.

The degree of treble rolloff is more pronounced with ribbon mics. The latter nevertheless tend to respond well to equalization. This makes it easier to restore the missing sparkle in recording cymbals, pianos or a clarinet. This type of microphone can also amplify the dynamics of the sound in an instrument with more fidelity and neutrality.

Ribbons are not the ideal option if you want to accentuate an acoustic instrument in a dense mix. They nevertheless deliver a very realistic sound in solo vocals and the most refined mixes. This is why ribbon models are often recommended as a microphone for singing, although they can be used with musical instruments.

The best Ribbon Microphone for recording your guitar: Avantone CR-14

The Avantone CR-14 is a passive microphone with a dual ribbon design. It stands out from other ribbon microphones for the vintage and contemporary it brings to a recording. This makes it a prime microphone for recording the sound of a guitar like the Lag Travel Signature Vianney electroacoustic.

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The Avantone CR-14 can go down to 30 Hz in its frequency response for a maximum value of 16 kHz . It is therefore quite responsive for reproducing the nuances of your acoustic guitar. This microphone also operates on an impedance of 600 Ohms , which ensures good signal transmission, even over a distance of 5 meters.

How to choose the microphone based on directionality?

Directivity indicates the direction in which a microphone can pick up sounds from a sound source and its sensitivity to the sounds generated. In particular, the microphone may be more sensitive to sounds generated in a specific direction than in another depending on the directivity. A microphone is a lot like human hearing in this respect. The sound generated from the front is often perceived with more force than that which comes from the back due to the shape of the pinna of the ear.

A figure called a polar diagram is used to represent the directivity of a microphone. The circle in the center of the diagram is the microphone. The other circles around the microphone represent the acoustic space in a 360 degree angle . The angles of 0 , 90 , 180 and 270 degrees correspond to the front, right, rear and left of the microphone, respectively.

An attenuation value indicated in decibels is also assigned to each circle in the polar diagram. The color curve in the diagram defines the sensitivity of the microphone taking into account two parameters. This is the angle between a particular sound source and the front of the recording equipment.

Microphones can be classified into two main categories regarding their representation in the polar diagram, namely:

  • Omnidirectional microphones
  • Directional microphones
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An omnidirectional microphone picks up sound with the same sensitivity from all directions . This type of microphone works on the basis of an acoustic pressure sensor . The sound wave only hits the membrane on one side. The other part of the membrane experiences constant atmospheric pressure, and begins to vibrate according to pressure variations.

A directional mic, on the other hand, is more sensitive to sounds generated in a specific direction than in other directions. This is due to the idea that this type of microphone works from a pressure gradient sensor . This is a type of membrane that can be hit by sound waves from both sides. The overpressures are the same from one side to the other. The membrane does not start to vibrate when a sound wave passes through it.

The bidirectional or figure-8 pattern microphone is the primary form of microphone with a pressure gradient sensor. Its technology can then be modified to create other types of polar patterns called "cardioid", "hyper-cardioid" and "super-cardioid".

Bidirectional microphones pick up sound with the same sensitivity from the front of the diaphragm as from the back. However, they are insensitive to sounds generated from the sides of the microphone. This corresponds to an angle of 90 degrees in the polar diagram representation. The vast majority of ribbon microphones use an 8 polar pattern . This directionality can nevertheless be chosen on certain models of condenser microphones with a large diaphragm .

A cardioid microphone can pick up voice and instrument sounds as they arrive through the front of the diaphragm . This type of microphone has the advantage of establishing reduced sensitivity to background noise and reflections of sound in space.

Hypercardioid or supercardioid polar pattern is available on microphones with an interference tube . The boom mic is a good example. The hypercardioid pattern tends to reject most sound sources to the back of the mic and to the sides. Microphones with this directivity are mainly used for sound effects and the creation of various sound effects . This is due to their ability to more easily isolate sound coming from a particular object or source.

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Hypercardioid microphones are much more precise than supercardioid directivity models in isolating sound from parasitic noise . They are mainly used during filming for recording dialogue on set.

You can also use them to record point sources as long as they are very isolated. High distortion also occurs as the microphone moves away from the pickup area , which is quite narrow.

The hypercardioid directivity also offers the possibility of capturing sounds at a great distance . Their technology is comparable to that of a zoom lens for cameras. This is why this type of microphone is often used for sound recording in a documentary , and especially on an animal theme.

It is important to note that microphones with a cardioid or figure-8 polar pattern are often subject to proximity effect. This is a phenomenon where the bass is progressively more pronounced the closer the mic is to a sound source. Such an effect can be advantageous or inconvenient depending on the recording technique that the sound engineer wishes to adopt.

The proximity effect is more interesting for a singer than it can be for a guitarist. They tend to make the voice sound more warm and intimate than it really is. Podcast creators and gamers may also appreciate this effect for the character it can add to the voice. It is also very common to have this kind of effect on a radio microphone.

Best mic for multi-pattern guitar recording: Audio-Technica AT4050

The Audio-Technica AT4050 immediately stands out with its large diaphragm condenser sprayed with gold and its brass acoustic element. It can thus deliver optimal performance, whatever the temperature while delivering great sensitivity to sound sources . The AT4050 can thus reveal all the subtlety of an acoustic guitar like the Core Earth 70 OP when recording sound.

The most distinctive aspect of the AT4050 microphone nevertheless remains its multiple directionality. You can choose between cardioid, omnidirectional and figure-8 polar patterns using the switch built into the microphone . The AT4050 is also very responsive with its frequency response of 20 Hz to 18 kHz and its maximum sound pressure level of 159 dB SPL .

Guitar recording with Audio Technica AT4050
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How to choose between a stereo and mono microphone?

A microphone is described as “ monaural ” when it can only deliver sound from a single capsule. However, it should not be understood that a mono microphone can only capture one sound at a time from a given object. A phono microphone will mainly process all the sounds captured by its polar pattern with a single channel . The captured sounds are then transformed into mono sound.

Phono microphones can therefore capture as many sounds as you want from a sound source. All these sounds will nevertheless be processed to reproduce a mono effect when mixing . Phone or camera microphones often have mono technology.

A stereo microphone is equipped with two capsules for processing the sounds captured. The latter will more specifically be processed through two distinct channels in the microphone. In particular, there are two techniques for processing sound with stereo microphones.

The first is called the X/Y method and consists of reproducing the operation of two directional microphones with cardioid polar pattern. The capsules of these two microphones are arranged so as to come as close as possible at an angle of 90 to 135 degrees .

The microphones are also oriented to the left and right respectively. The signal from one of the microphones will then go to the left recording track. The one on the other microphone will be dedicated to the right track.

The SYNCO V10 is a good example of a microphone based on the X/Y technique . This model is equipped with a small diaphragm for recording musical instruments and vocals. It is nevertheless distinguished by its X/Y adjustment, which gives it the ability to establish a picture live . This is why this model is very popular for outdoor recordings.

How to choose between a stereo and mono microphone?
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The other method adopted in the operation of a stereo microphone is the A/B technique . Two omnidirectional microphones are required for this technique. The latter are positioned 30 cm from the sound source , with a distance of 60 cm between their respective capsules. The distance between the sound source and the capsules themselves can be changed depending on the type of recording to be obtained. It is quite rare to find a stereo mic that can reproduce this technique.

The mono mic processes sounds through a single channel, without any soundstage difference between recorded sounds. Such a microphone can be moved freely to capture the perfect sound . Such freedom is not permitted in the case of stereo microphones. The sound of the recording will indeed change depending on where the microphone is placed. It is therefore essential to place the stereo microphone in a location where the sound source is optimally captured.

However, stereo microphones have the advantage over stereo microphones in phase interference. Sound waves tend to interfere with each other when sound is generated in multiple locations. This same problem applies to a mono signal broadcast on a stereo system. The two signals are in fact generated identically by the microphone.

This problem occurs for recordings made with a stereo microphone. Each channel of the stereo system will in fact reproduce a distinctly processed sound from the microphone. However, this should not be taken to mean that mono microphones are uninteresting compared to stereo microphones. These two types of microphones can have their respective uses.

When choosing a microphone for guitar recording, a stereo microphone like the Shure SM81 is most suitable, because the music is more lively with two channels . A mono microphone is more flexible in placement. It is the right choice of microphone for situations that do not require the reproduction of a soundstage. They can in particular be used for a podcast , an interview or a vlogging .

What to choose between a stereo and mono microphone?
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The best stereo microphone for recording an acoustic guitar: Samson C02

The Samson C02 is a compelling choice for those looking for a stereo microphone suitable for recording an acoustic guitar . This microphone is designed in a very small format, which makes it easy to use for setting up a stereo recording.

Its small size should not mislead you as to its performance. It is in fact equipped with a tube condenser for the elimination of ambient noise during recordings. However, many condenser microphones with a large diaphragm do not offer the same efficiency. So you can capture the full essence of a guitar like the Taylor 214ce with this microphone.

What connectivity technology does the microphone use?

Microphones can be classified into two main categories depending on the connection method. These are wired microphones on the one hand and wireless microphones on the other. Wired microphones can in turn be classified into models with analog or digital connection.

Wired models are a priori the most suitable for choosing a microphone for guitar recording. A wireless microphone can nevertheless deliver good performance in this task depending on its build quality.

Analog connection types for microphones

There are three main types of analog connection for microphones, namely XLR , TRS and TS . XLR connections have a male head for input and a female head for output. They can be available in several variants depending on the number of pins for the connectors.

A basic XLR connection thus offers 3 pins, but there are also 7 pin models. There are also mini-XLR connections , which also have 3 pins, but come in smaller dimensions. The TRS function as inputs and outputs. TS connections only offer two contact points for connecting the microphone.

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The best analog connection microphone for recording guitar: Rode NT1-A

The Rode NT1-A microphone has strong rivals for the title of best XLR connection microphone . This includes the Shure SM58 and the AKG P420. The NT1-A nevertheless surpasses these two microphones in the quality of sound it delivers when recording an acoustic guitar like the Yamaha FG800.

power of 24 to 48 volts is required for operation of the Rode NT1-A. This can be delivered by the audio interface or the microphone preamp to which the NT1-A is connected. The microphone nevertheless comes with several accessories for greater ease of use. This includes an external pop filter, shock mount and 6 meter XLR cable.

Digital connection modes for a wired microphone

Digital connections for wired microphones can take three forms. The first is that of interface cables, namely USB, FireWire and Thunderbolt. A modern microphone with a digital connection is in many cases designed or Thunderbolt microphone

A USB-C to USB-A cable, like the one offered by DPA, is often necessary to connect a USB microphone to an audio interface. However, there are USB microphones based on a lightning cable for iPhone or iPad (the IK Multimedia IRig Mic HD 2 USB microphone for example).

The USB-C head of the cable will plug into the microphone's USB port if necessary. The Lightning head of this cable will be plugged into the micro-USB port of the phone or touchscreen tablet.

The other type of digital connection you can get for a microphone is MIDI or “Musical Instrument Digital Interface”. This type of connection is especially useful when you want to connect the microphone to a sequencer or synthesizer .

Finally there are microphones based on a Cat5e connection . This is the same type of cable used in the field of telephony. Using a Cat5e connection significantly reduces the noise level in the signal in addition to increasing transmission capacity. Such a connection is nevertheless quite rare for a home studio and is especially suitable for the most prestigious studios.

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Best USB Microphone for Guitar Recording: Rode NT-USB

There is more than one model that can be mentioned when it comes to a good USB microphone for acoustic guitar . This includes the Blue Yeti USB and the Shure Motiv MV5 mic . However, the Rode NT-USB remains the most popular choice when it comes to USB guitar mics, and for good reason.

The Rode NT-USB microphone gives character to recordings without adding too much color thanks to its cardioid polar pattern condenser . It can be used with a PC, a Mac or an iOS smartphone. Its sturdy metal body is equipped with a 1/8 headphone jack and two control buttons. One is for mixing sources while the other controls headphone volume. This microphone also offers a frequency response of 20 Hz to 20 kHz for an SPL of 110 dB .

Connectivity Technologies for a Wireless Microphone

Wireless microphones work based on a wireless receiver that processes the signal generated at their outputs. The receiver receives the signal and processes it before outputting it in the form of a balanced XLR signal. There are mainly two types of wireless microphones , namely the handheld microphone and the clip-on or “Lavalier” microphone .

Handheld microphones are a wireless variant of dynamic microphones intended for stage use. They are very popular for live performances due to their propensity to avoid handling noise .

Lavalier microphones are widely used for interviews and other types of mobile recording due to their small size. The Rode SmartLav 4 is among the best clip-on mic models when it comes to mobile recording.

Bandwidth is an important consideration when selecting a wireless microphone. On this point, a distinction should be made between VHF and UHF microphones. VHF mics operate over a bandwidth of 30 Hz to 300 MHz compared to 300 MHz to 3000 MHz for UHF mics.

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UHF microphones have the advantage of being less subject to interference than VHF microphones. Most wireless microphones mostly operate on the UHF band. The same goes for wireless headphones and other non-wired monitoring equipment.

The advantage provided by a UHF microphone, however, is only felt when the microphone is used in an environment with several wireless devices. A VHF microphone is therefore sufficient when there are few wireless devices in the recording environment.

Best Microphone for Wireless Guitar Recording: Shure PGXD24

The Shure BLX24 is the wireless equivalent of the Shure SM58 microphone in terms of performance and convenience when choosing a mic for guitar recording. This microphone also works from an SM58 wireless transmitter with a maximum range of 100 meters . The transmitter in turn operates at a frequency band of 823 Hz to 832 MHz for a transmission range of 50 Hz to 15 kHz .

You can therefore have great freedom in positioning the microphone without fear of interference during recordings. The microphone has also been designed for optimal isolation from sound sources and low sensitivity to noise. There is no risk of adding unwanted sounds to the recording of a guitar like the Taylor 110e.

What technical specifications should be considered when choosing the microphone?

Technical specifications should be considered carefully when choosing any studio equipment. A microphone intended for guitar recording is no exception. You should especially pay attention to the frequency response, impedance and maximum sound pressure level. Added to this is the sensitivity of the microphone and the presence of a high-pass filter.

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Microphone frequency response

Frequency response is the extent of frequencies that a microphone can pick up within the human audible frequency range. This range is set to values ​​from 20 Hz for low frequencies to 20 kHz for highest frequencies.

An acoustic guitar covers almost the entire spectrum of frequencies audible to humans, namely from 20 Hz to 20 kHz . The sound of the pick and high harmonics on steel strings can cross the ultrasonic threshold. Nylon strings can reach the upper octave of human hearing, namely between 10KHz and 20KHz .

The lowest fundamental value in the spectrum of an acoustic guitar is a priori 80 Hz . The same goes for an electric guitar like the Fender Player Series Strat MN PWT . However, starting and stopping notes combined with the sound of the sound box can cause the instrument to go below 20 Hz . A frequency response of 20 Hz to 20 kHz is therefore the recommended value for recording a guitar.

Microphone impedance value

Impedance can be defined as the resistance to alternating current in an electrical circuit when a voltage is applied. The unit of measurement for impedance is the same as that for resistance, namely the Ohm. Alternating current in a microphone takes the form of an audio signal. The impedance of a microphone thus describes the resistance of the microphone to this signal when a voltage is applied.

Resistance occurs most especially at the microphone output. In this case we are talking about an output impedance . The microphone creates an electrical circuit with the preamp or audio device it is connected to. The device in question sets the input value for the audio signal to be transmitted to the microphone. This audio device is also said to define the input impedance of the audio signal .

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Mic signal transmission for guitar recording is optimal when the output impedance is a fraction of the input impedance. Low impedance microphones like the Neumann brand TLM49 , namely between 600 ohms or less , perform the best in terms of sound quality. This is true even when using cabling longer than 5 meters for signal transmission.

Maximum sound pressure levels

Maximum sound pressure or SPL is often misrepresented as the maximum volume a microphone can handle before failing. However, there are no practical limits to the volume a microphone can handle.

The maximum sound pressure level is actually the level at which the signal distorts at the output of a microphone. This level is measured in decibels. The signal is distorted when the total harmonic distortion or THD has exceeded a specific threshold.

Total harmonic distortion defines the ratio between the sum of the harmonic powers and the power of the fundamental range . The THD value is indicated as a percentage. The SPL value of a microphone should be set relative to a THD as low as 0.5% .

Dishonest manufacturers set SPL values ​​at a higher THD. They may even go as far as not listing the THD in the mic specs. The microphone then appears to have a higher maximum sound pressure value than it really is. It is therefore essential to consider the value of SPL in the same way as that of THD when evaluating a microphone.

The tolerance threshold for human hearing is defined at a maximum sound pressure of 140 dB . The jet engine of a fighter jet can generate an SPL of 125 dB at a distance of 100 meters . It seems surprising then that modern condenser microphones can achieve an SPL of around 130 dB at a THD of 0.5% .

The truth is that the SPL of a microphone is not measured the same way as that of human hearing. SPL is also not as important for passive technology microphones as it may be for active mics.

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Passive microphones (like the MXL R144 ) are not very sensitive to distortion. The maximum sound pressure is not indicated in the technical specifications of many moving coil microphones. It is indeed unlikely that a dynamic microphone with passive technology could record a sound source strong enough to distort it.

The electronic components of a passive microphone are also more durable and more resistant to overload . The signal from a passive microphone is only distorted if the SPL is increased to the point of physically damaging the capsule diaphragm. The latter can no longer vibrate to create an electrical signal. However, such a scenario is very rare in practice.

The noisiest environment to place a passive microphone would be inside a bass drum. However, it is unlikely that the sound will exceed 155 dB , even with the heaviest one. So you don't have to worry about SPL in the case of passive microphones. This includes the vast majority of dynamic description microphones.

The situation is different for active technology microphones such as ribbon and condenser microphones. The SPL value is always indicated for active microphones. However, the diaphragm of an active microphone does not risk deforming by exceeding the SPL value.

The deformation suffered by an active microphone is linked to an electrical overload. The active circuit is especially overloaded by the signal coming from the capacitor capsule. Many manufacturers tend to directly inject a 1 kHz tone into the condenser circuit to simulate microphone distortion. The diaphragm is completely bypassed in this context.

A voltage value is obtained by increasing the pure signal voltage to a THD of 0.5% . It is then easier to calculate the voltage applied to a theoretical sound pressure level measured in dB SPL.

At least this is the case if the nominal sensitivity of the microphone is established. Condenser microphones can notably support high SPL when equipped with an attenuation switch . The latter is often designed as a switchable function.

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It is overall more relevant to consider the SPL value when purchasing a condenser or ribbon microphone. It's also important to consider SPL when recording sound from a kick drum or guitar amplifier. This makes it a parameter that should not be overlooked when choosing the microphone for an acoustic guitar recording. This through a microphone positioned in front of an amplifier .

Microphone output sensitivity

Not all microphones can have the same sensitivity to the same sound source. This is due to the difference in output levels between these different microphones. It is this difference which is illustrated by the notion of sensitivity of a microphone. This involves measuring the ability of a microphone to create electrical voltage by converting acoustic pressure.

The microphone signal is in fact amplified by the preamplifier before entering the mixing console. High sensitivity means that the microphone can produce a level suitable for that mix track without requiring a lot of preamplification . The sensitivity of a microphone can be measured in millivolts ( mV ) by Pascal in most European countries. This means that 1 Pascal corresponds to a sound pressure of 94 dB SPL .

Condenser microphones often have higher sensitivity than dynamic microphones. The most common values ​​for this type of microphone are 8 to 32 mV/Pa . Dynamic microphones have a sensitivity of 1 to 4 mV/Pa .

It is especially important to consider microphone sensitivity in the case of dynamic and ribbon microphones. This specification is less relevant for condenser microphones as they can still establish a sensitivity above about 8 mV/Pa .

However, it is wrong to think that a poor level of self-noise can be compensated by high sensitivity. Manufacturers like Neumann state that the gain sensitivity of the mic should define the gain adjustment in noise measurement .

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However, it is advantageous to use a high sensitivity microphone if used with an inexpensive preamp. These tend to produce a dull sound even when the gain is set above 50 dB . Such a level of gain is rarely necessary for a high sensitivity mic.

Presence of a high pass filter

A high pass filter or HPF is an element of the electronic circuit of a microphone. It sets a specific point from which signal frequencies can pass. The point set for the passage of frequencies is also called the cut-off point .

Signal frequencies that are below this cutoff point are attenuated by the high-pass filter at the microphone output. These attenuations cause a change in the frequency response of the microphone.

High-pass filters may also be referred to as " low-cut filters " or " low-cut filters" . These alternative designations refer to the primary function of the high-pass filter. This involves removing low frequencies to promote the passage of high frequencies.

The high-pass filter function is especially useful for recording instruments that are not very focused on low frequencies. Acoustic guitar recording as a good example. This feature is also usually designed to be switchable. This means that it can be activated or deactivated at any time depending on the needs of the recording.

In summary

The following points should be considered when choosing a microphone for guitar recording:

  • Sound reproduction technology: condenser, dynamic or ribbon.
  • Microphone directivity: omnidirectional, directional
  • Sound processing channels: mono or stereo microphone
  • Connectivity mode: wired or wireless microphone
  • Technical specifications: impedance, sensitivity, maximum sound pressure level, presence of a high-pass filter.