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Contents

• Introduction
• Types of Microphone
  • Dynamic or Condenser
  • Omni- or Uni-directional
  • Low- or High-impedance
  • Boundary or Conventional
  • Wired or Radio
  • Hand-held or Hands-free
• Microphone Noise Levels
  • Sources of Noise
  • Types of Noise Specification
  • Noise Weightings
• Use of Microphones
• Care of Microphones
• Microphone Selector − microphones ordered by application and price
  • Microphone Details − 294 microphones listed

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Introduction

A microphone ('mic' for short, pronounced "mike") is a device for converting audible sound into a signal. To accomplish this task with the optimum efficiency and quality of result requires a type of mic that is appropriate to the particular situation, so there are many different types of mics − some designed for very specific applications and others that are more general purpose.

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"When you have exhausted all possibilities, remember this: you haven't." − Thomas Edison.

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Types of Microphone

Mics can be categorised in several different ways. The most important of these categories are described below.

Dynamic or Condenser

All types of microphone incorporate some form of diaphragm − this is a small thin surface which vibrates in sympathy with the sound pressure waves reaching the microphone. However, dynamic and condenser mics vary in how these vibrations are used to produce an electrical signal.

• In a dynamic mic, sound is converted to an electrical signal by the vibrations of the diaphragm causing the vibration of a coil in a magnetic field − effectively an electrical generator on a very small scale. (This is the exact opposite of the operation of a speaker driver.) As this produces sufficient signal level for direct connection to a PA system, no amplification of the signal is required within the mic. Dynamic mics are most useful for close-proximity applications (i.e. 0 to 15 cm) such as lead vocals, guitar amplifiers, etc. The sensitivity of low impedance dynamic mics is typically in the region of 1 to 3 mV/Pa. (Impedance is explained later on this page.)
• In a condenser mic (also called a capacitor mic), sound is converted to an electrical signal by the vibrations of the diaphragm causing changes in the capacitance of a charged capacitor. This is achieved by the diaphragm itself being one of the plates of the capacitor. As this produces a very small signal level, some initial amplification of the signal is required within the mic itself. This internal amplifier may be powered either by an internal battery or by power supplied from the mixer (usually at 48 volts d.c.). The latter arrangement is called phantom powering and is only possible when using a balanced connection between the mic and the PA system. (For mic connection types see Low-impedance or High-impedance.) Unfortunately the amplifier inevitably introduces some noise into the mic signal − see the Microphone Noise Levels section below. Condenser mics are most useful for larger distances between the sound source and the mic (i.e. 15 cm upwards), such are encountered with lecterns and with overhead miking of drum kits, choirs, theatre stages etc. They can be more prone than dynamic mics to making a "popping" sound when used close-up with a "breathy" sound source such as a voice or a wind instrument, though this problem can be reduced with a windshield. They are generally more fragile than dynamic mics, so are rarely employed for rough stage use or in very high SPL applications. They are however capable of a higher quality sound than dynamic mics, and the best versions are therefore extensively used in studio recording work. The sensitivity of low impedance condenser mics is typically in the region of 3 to 20 mV/Pa.

Omni-directional or Uni-directional

• Omni-directional mics pick up sound with equal sensitivity from all directions. This is not normally useful for PA work, because in PA work each mic is targetted at a single sound source (so that the amplification given to that sound can be controlled separately from others, and so that pick-up of unwanted sounds can be minimised). Their application is generally limited to recording work (particularly of ambient sounds) and to sound-level measurement.
• Uni-directional mics pick up sound with greater sensitivity from the front than from other directions. There are several variations on this theme. Each of the following types is illustrated with a polar response diagram, in which increased sensitivity in a particular direction is indicated by the line on the diagram being closer to the outer circle. Imagine the microphone diaphragm being located at the centre of the circle, with the most sensitive end (or side) of the microphone facing towards the top of the circle. So, the upper-most point of the line on each diagram indicates the sensitivity at the front of the microphone, or at '0 degrees' − i.e. the on-axis response, and the lower-most point indicates the sensitivity at the back, or at '180 degrees'. (The diagrams below are simplified to illustrate typical mid-frequency responses; in practice the polar responses vary with frequency, so check the manufacturer's specifications.)

  Sub-cardioid mics have a very gradually reducing sensitivity from the front to the back, maintaining some sensitivity at the back.
  Cardioid mics have a gradually reducing sensitivity from the front to the back, with very little sensitivity at the back.
  Super-cardioid mics reduce their sensitivity from the front to the sides at a faster rate than cardioid types, reaching a minimum sensitivity at an angle of around 120-140°, measured from the front. The sensitivity then increases again towards the back, but the sensitivity at the back is still very much less than at the front.
  Hyper-cardioid mics provide even less sensitivity at the sides than do super-cardioid types, at the expense of a little more sensitivity at the back. Therefore, a monitor speaker should never be placed directly behind this type of mic. Their minimum sensitivity is at an angle of around 100-120°, measured from the front.
  'Rifle' or 'shotgun' mics are the most directional type, so-called because of their long rifle-like barrels. They are generally used only for long-distance miking (more than 2 metres from the source), e.g. for theatrical work, and should be located such that the back of the mic is not exposed to unwanted sounds.

• Bi-directional types

  Although not featured in the title of this sub-section (as they are rarely used in live PA work), bi-directional mics get a mention here for completeness. They pick up sound with equal sensitivity from two opposite directions, shown in the diagram as the front and back; in practice however, as these are usually side-addressed types, the sensitive directions are most commonly on two of its sides.

Low-impedance or High-impedance

• Low-impedance mics have an impedance of from around 50 to 600 ohms and may only be connected to low-impedance mic inputs. They come in two varieties, each of which should only be connected to the corresponding variety of low-impedance mic input:
  • Unbalanced, where one of the two signal-carrying conductors of the interconnection between the mic and the system is also the signal earth conductor of the interconnection, usually provided by the screen of the cable(s). With this arrangement, the cables are prone to pick-up of interference from stray magnetic fields, earth loops and radio signals, and so these types of mic are suitable only for use with moderate lengths of cable (up to around 10 metres). They are relatively uncommon.
  • Balanced, where the two signal-carrying conductors of the interconnection are separate conductors from the signal earth (cable screen) of the interconnection. This arrangement is highly immune to pick-up of interference, and so may be used with very long lengths of cable (up to 200 metres), provided it is of good quality. Also, balanced connections allow the use of phantom powering. Nearly all professional and semi-professional mics are of this type. See the diagram for connection arrangements.
• High-impedance mics have an impedance very much greater than 600 ohms − usually in the range of 5,000 to 15,000 ohms (5 kilohms to 15 kilohms). They may only be connected to high-impedance mic inputs. Such inputs are rare in PA systems, as they may only be used with short cables (less than 5 metres) if the signal is not to suffer from a reduction in high audio frequencies (treble), resulting in a loss of clarity.

To enable a high-impedance mic to be connected to a low-impedance input, or vice versa, a microphone matching transformer can be used. To minimise loss of signal quality, it is important to use a good quality transformer and to locate it so as to minimise the length of the high impedance cable run. To avoid pick-up of hum by the transformer, do not locate it close to mains-powered equipment.

Boundary or Conventional

• A boundary mic is a special type which when placed on a surface utilises the sound energy collected at that surface to provide a greater sensitivity (and therefore, potentially, a better signal-to-noise ratio). Many such mics are generally equally sensitive to sounds in all directions above the surface (a so-called 'half-omni' response pattern) and most are condenser types. Typically used for speech, where a convenient surface such as a desk or lectern is available, though some types have a 'built-in' plate to act as the surface. Also known as a 'pressure-zone microphone' (PZM), which is a trademarked name.
• By "conventional" here, we just mean "not a boundary mic".

Wired or Radio

• Wired mics connect to the PA system by means of a cable. The cable usually attaches to the mic by means of a 3-pole XLR connector.
• Radio (or 'wireless') mics contain a battery-powered radio transmitter. The radio signal from this transmitter is picked up by a receiver which is connected to the PA system. The mic and the receiver are purchased as a pair and are referred to as a "radio mic system".

  Please note that although the information presented here is given in good faith, it is only intended as a general guide. The regulations concerning legal use of radio systems are varied from time to time and may have recently changed. It is your responsibility to ensure that all radio systems under your control are operated legally, and that all equipment purchased or hired is suitable for the intended use and will remain so for the intended period of time. Refer to this site's Disclaimer.

  Most radio mic systems use a frequency-modulated (FM) radio signal at VHF or UHF frequencies, or in the 1.8 or 2.4 GHz frequency bands. Each system does not operate at a single radio frequency, but rather occupies a narrow range of frequencies approximately 0.2 MHz wide. However, in practice this range is identified by reference to the system's carrier frequency, which is the frequency at the centre of the occupied radio frequency range. (This occupied range may be termed a 'channel', however in order to avoid confusion with the UHF TV channel numbers referred to below, we avoid that usage of the term 'channel' here and just refer to a 'frequency' instead.)

  The frequencies used are either "licensed" or "de-regulated". Use of a licensed frequency requires payment of an annual license fee. Use of the de-regulated frequencies is free, but as their use is uncontrolled by licensing it is more likely that interference will be experienced from other users. Warning: Some UHF systems will allow you to set the operating frequency to a value outside the legal ranges, but this is clearly very inadvisable and may incur severe penalties. All systems, regardless of whether licensed or de-regulated frequencies are used, must comply with the appropriate standards. In particular, these standards put limits on the maximum power output of the transmitters and on the maximum levels of spurious frequencies that may be radiated.

  • VHF:
    For VHF systems in the UK there are:
    • 7 de-regulated frequencies (originally just 5) in the band 173.7 to 175.1 MHz.
    • 6 frequencies that are licensed for single-site use (in this case it is the site that is licensed, not the equipment).
    • 15 frequencies that are licensed for any-site use.
    
    The frequencies are listed below.

• • UHF:
    Many UHF systems are tunable, i.e. can be adjusted to operate on one of several frequencies. UHF systems are generally better than VHF ones, as there is less radio-frequency interference around at UHF − provided that the frequencies used are chosen carefully.
    
    Most UHF systems in the UK operate now within the frequency range known as 'channel 38' (licensed systems) or within the frequency range known as 'channel 70' (licence-free systems). However, the standard 'channel 38' licence now also permits use of 823 to 832 MHz and the 1.8 GHz band, subject to conditions.
    
    The channel numbers referred to here (such as 38 and 70) relate to 8 MHz wide 'slots' in a band of the UHF spectrum originally allocated for terrestrial broadcast TV (up to channel 68). This band starts at 470 MHz, the first-numbered slot being called channel 21. [Why? - because lower-numbered TV channels existed long long ago, broadcast at VHF.] So, for example, channel 22 starts at 478 MHz and ends at 486 MHz. [Note that, since the advent of digital TV, these UHF channel numbers are effectively 'invisible' to the general public; they are not the same as the advertised TV programme channel numbers allocated for Freeview digital TV transmissions, and there is not a 1-to-1 mapping between the two sets of numbers.]
    
    
    • Channel 38 (606 to 614 MHz) is now allocated as an any-site ('shared use') licensed band for UHF PMSE radio systems in the UK, replacing the 14 specified licensed frequencies previously available within Channel 69 (854 to 862 MHz). This change, which completed at the end of 2012, is part of the move to clear the so-called '800 MHz band' (790 to 862 MHz) for other services. Channel 38 is generally able to accommodate at least 8 simultaneous system frequencies without mutual interference (depending on the equipment specifications).
      
      
    • The lower part of channel 70 is allocated as a de-regulated band that is wide enough to accommodate up to around 6 or 7 radio systems. This band is sometimes referred to as '863 to 865' (its approximate frequency range), or as the ISM or ETS band. Its use for PMSE applications remains unaffected by the move to clear the so-called '800 MHz band' (790 to 862 MHz) for other services throughout much of Europe. Note that as the 863 to 865 MHz band is not reserved for professional entertainment purposes but is available for general use, interference from other types of equipment may sometimes be experienced. For example, these frequencies are used by some home entertainment equipment such as wireless headphones. In addition, the maximum permissible power output of channel 70 equipment is less than that for channel 38 equipment.
      
      
    • The 823 to 832 MHz band was added in 2015 in order to enable a larger number of systems to be used together, and for compatibility with European frequency allocations. It is a licensed band, included within the standard shared-use 'channel 38' licence. 823 to 832 MHz consists of most of channel 65 and the first part of channel 66, so may variously be referred to as 'channel 65', 'channel 65/66', etc.
      
      
    • Single-site ('co-ordinated use') licences may be granted for PMSE use on frequencies within certain ranges used for TV broadcasting, particularly 470 to 550 MHz and 614 to 790 MHz (channels 21-30 and 39-60). This is possible because within the service area of each broadcast TV transmitter there are channels that have to remain unused for TV broadcasting, in order to avoid interference with TV transmissions in adjoining areas and for other technical reasons. Controlled use of radio systems on specific frequencies within some of these unused channels may be judged not to be detrimental to TV broadcasts, because of the (relatively) very low transmitted power level of radio systems and the narrow bandwidth they employ. In the UK, such PMSE use was until the end of 2012 mostly within channels 67 and 68 (838 to 854 MHz), but these frequencies are no longer available for this purpose. (In fact the whole of the range 790 to 862 MHz, channels 61-69, is now unavailable, with the exception of 823 to 832 MHz.)

    The channel 38, 65/66 and 70 frequencies are listed below.
    

• • 
    The illustration below provides a visual representation of the present UHF channel allocations in the UK, however see the Important Note below it.
    

    Important Note: It is planned to reallocate the so-called '700 MHz band', occupying channels 49-60 (694 to 790 MHz) for 4G use, making this band unavailable for licensed co-ordinated frequency PMSE use in the UK after April 2020. Furthermore, since all broadcast TV transmissions in that range will by then have had to move to channels below 49, the space available for PMSE use below channel 49 will be decreasing as that date approaches. Therefore, some co-ordinated frequency PMSE equipment currently using frequencies below 694 MHz may have to switch to other frequencies in order to avoid new interference problems (or be replaced if that is not possible), by various dates prior to April 2020. It would be highly advisable to take these planned changes into account when purchasing new radio mic or IEM equipment. (Channel 38 will remain available for shared frequency usage.)
    

  • 2.4 GHz:
    Systems operating on the 2.4 GHz band (2400 to 2483.5 MHz) are now popular where a large number of systems (e.g. more than 20) are to be used simultaneously. Furthermore, in some countries certain UHF frequencies are being withdrawn for radio microphone use and so this band may be the only practicable option. However, as it is a de-regulated band, care must be taken to select frequencies that are not subject to interference from other types of equipment operating on this band in the vicinity such as Bluetooth, Wi-Fi and wireless DMX devices. A particular caution on WiFi is necessary because of mobile phones carried by audience members; 2.4 GHz interference may be minimal during system set-up in the absence of an audience but may increase dramatically once the audience arrive, as their phones search continually for a WiFi network. Some systems utilise digitally-coded transmission, which can assist in the avoidance of interference from other equipment. Note that systems operating at such high frequencies usually have a shorter range and are more prone to disruption by physical obstacles in the line-of-sight path.
  • 1.8 GHz:
    Systems operating on the 1.8 GHz band (1785 to 1805 MHz) are becoming more popular, as they are free from the interference caused by 2.4 GHz devices. However 1.8 GHz is a regulated band, so these systems do require a licence and there are some geographical restrictions. The same comment regarding high frequency systems as for 2.4 GHz systems applies.
  • 1.9 GHz:
    Some licence-free systems operating on the 1.9 GHz band are available, however most of these are intended for speech-only applications such as ENG, conferencing and other spoken voice purposes.
  • 1.5 GHz:
    The 1.5 GHz band (1518 to 1525 MHz) is also available for some PMSE applications, but is separately licensed. This band is additionally used for the downlink for certain satellite phone systems (mobile satellite systems, or MSS), but problematic interference with PMSE systems from MSS is considered unlikely.

  Receivers are either 'single-channel' − better called 'non-diversity' − or are 'true diversity' types:

  • 'Single-channel' means that the radio signal (usually picked up on a single aerial) is processed by a single set of receiving electronics. (Note that this use of the term 'channel' is unconnected with TV channels.) These types are prone to "drop-outs" − temporary interruptions of the audio signal caused by temporary reductions in the received radio signal strength (due to reflections of the signal and physical obstacles in its path). The receiver aerial is generally best set vertically. Some single-channel receivers are equipped with two aerials, even though they have only one set of receiving electronics − these may perform a little better than single-channel receivers with only one aerial, but fall far short of the performance obtained from true diversity receivers. (Take care to avoid confusion between this usage of the term 'single-channel', and its usage to distinguish a receiver from the (rare) types that can accept radio signals on more than one transmission frequency at the same time.)
  • 'True diversity' means that the radio signal is picked up on two aerials, each connected to a separate set of receiving electronics − the output of the receiver is provided from the set which is giving the best quality signal at any moment in time, or is a combination of the two. True diversity receivers are much less prone to drop-outs than single-channel types. The aerials are generally best set at between + and − 30 to 45 degrees from the vertical, i.e. spreading apart at between 60 and 90 degrees to each other.

  Some receivers provide an audio output intended for connection to a line input of the PA system, whilst others have outputs intended for connection to a mic input. Some types may provide both kinds of output, or a single output of adjustable level.

  When several radio mics need to be operated simultaneously, each system must be set to a different frequency. Furthermore, in order to avoid intermodulation interference between the systems, the frequencies selected must be chosen from a compatible set for the particular make and type of system being used. The maximum number of frequencies in a compatible set will depend upon the quality of the system. For example, in the case of Sennheiser's UHF systems:

  • The eW100 G1 and G2 systems allow a maximum of 4 simultaneous frequencies − a compatible set in the UK de-regulated band is 863.1, 863.5, 864.3 and 864.9 MHz.
  • The eW100 G3 system allows a maximum of 6 simultaneous frequencies − a compatible set of 5 in the UK de-regulated band is 863.1, 863.4, 863.75, 864.225 and 864.550 MHz.
  • The eW300 range allows up to 8 simultaneous frequencies and the eW500 range up to 20.
  • The only 4 frequencies available on the freePORT™ system (frequency range E) are 863.1, 863.7, 864.1 and 864.9 MHz; these can be used simultaneously.
  Preferably, consult the appropriate manufacturer's information for the recommended frequency combinations relevant to your specific system(s). It is very inadvisable to simultaneously operate systems from different manufacturers, or even different product ranges from the same manufacturer − except that there is very unlikely to be any interference between good quality systems operating in entirely different bands − i.e. between VHF, UHF, 1.8 GHz and 2.4 GHz systems. In the absence of manufacturer's information, for channel 38 equipment select from the following set of ten frequencies (taking into account the permitted range for the operating location and the type of use): 606.6, 607.5, 608.15, 609.15, 609.95, 610.55, 611.25, 612.3, 613.15 and 613.5 MHz. If fewer than 10 frequencies are required, then first discard 609.95 and 610.55, then 607.5 and 612.3 (unless the remaining frequencies are unusable, e.g. are not available on your equipment, or are affected by interference from other sources).

Hand-held or Hands-free

• Hand-held mics are generally about 6 to 7 inches (15 to 18 cm) long and 1.25 inches (3 cm) in diameter. They may be held in the hand or placed in a clip on a mic stand. Note that many radio mics have a slightly larger diameter than wired types, and therefore will not fit into 'standard' sized mic clips. Mic clips fix to the stand by means of a screw thread, of which there are three common types:
  • 5/8 inch 27 turns per inch (a large diameter fine thread) − sometimes referred to as an 'American thread'.
  • 1/2 inch (a medium diameter fine thread) − less commonly encountered.
  • 3/8 inch Whitworth (a small diameter coarse thread) − sometimes referred to as a 'Euro thread'.
  In case your mic clip doesn't fit your stand, thread adaptors are available.
• Hands-free mics are generally much smaller and are either body-worn (e.g. clipped to a lapel or tie, or attached to a head-set) or are suspended by their cable (e.g. above a choir). For theatrical applications, they are often hidden in the hair (or wig). Body-worn mics are usually of the radio type, and are used in conjunction with a bodypack. A body-worn mic worn on the chest is also known as a lavalier mic. Many types can be purchased with either an omni-directional or uni-directional pick-up pattern. An omni-directional pattern can often be a good choice for chest or lapel-worn mics, provided that acoustic feedback is not likely to be a problem (e.g. for recording or broadcast applications, or where the mic is always placed high on the chest and the user has a strong voice). This is because these types are less susceptible to changes in pick-up level due to head movements, and are less likely to pick up unwanted sounds due to friction with clothing. However, in live PA situations where feedback may be a problem, or where pick-up of ambient sound needs to be minimised, the uni-directional types can be appropriate provided that they are worn at the correct angle and that head movements relative to the body are fairly small; these types typically have a cardioid pick-up pattern.

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Microphone Noise Levels

Sources of Noise

Unfortunately, the output of a microphone does not consist only of a signal corresponding to the sound waves that the mic picks up. The output also contains noise − unwanted signals originating from:

• Thermal effects − the vibration of electrons within the resistive elements of the mic.
• Pick-up of interference by the mic, especially hum due to stray magnetic fields from equipment and mains cables.
• In a condenser mic, active components within the built-in pre-amplifier.

Thankfully, a very low noise output level is not usually requirement in live PA work − except for long-distance miking applications (as a large amount of gain must then be applied to the output signal). It is however often a requirement for recording and broadcast purposes, in order to cater for listening environments with a very low ambient noise level. Note that, to take advantage of a microphone's very low noise level, the pre-amplifier that is used with it must have a correspondingly low equivalent input noise (EIN) − more on this later.

In order that the noise levels produced by different microphones may be compared, their specifications usually include figures to indicate how much noise output can be expected. Noise measurement and specification is a fairly complex subject in its own right, so the information given here is simplified to meet our present needs.

The first of the above three sources is relatively insignificant (see the definition of thermal noise) and the second is very difficult to quantify in practice, as it depends on the type and proximity of other equipment. Therefore only the last source is usually considered, and so noise specifications are generally given only for condenser microphones.

Types of Noise Specification

The noise specification of microphones is generally given in one of two ways:

• The equivalent noise level, or 'self noise'. This is the sound pressure level (SPL) that would have been needed to cause an output level equal to the amount of noise output actually produced, had the mic produced no noise at all. Put another way, it is the sound level that would appear to be present at the location of the mic if it were placed in a room that is actually totally silent, based on the measured noise output level of the mic under these circumstances. It is sometimes just referred to as the 'noise level' of the mic.
• The signal-to-noise ratio (SNR). This is the difference in level between the noise output of the mic and the wanted signal output which that mic would produce when exposed to some standard sound level − usually 1 Pa (94 dB) SPL.

Thankfully, it is very easy to convert between these two types of specification. The difference in level between the signal and the noise at the output of the mic will be the same as the difference in sound level between the wanted sound and the apparent noise at the input of the mic. Therefore if a mic is quoted as having an equivalent noise level of 15 dB SPL, the signal-to-noise ratio will be 94 − 15, or 79 dB. Similarly, if the signal-to-noise ratio is quoted as 77 dB, then the equivalent noise level is 94 − 77, i.e. 17 dB SPL.

The dynamic range of microphones is usually quoted as its maximum SPL minus its equivalent noise level.

The previous two paragraphs may be summarised as follows:

• Equivalent noise level (dB SPL) = 94 − SNR
• Equivalent noise level (dB SPL) = Max SPL − Dynamic range

To convert an equivalent noise level value in dB SPL into an electrical noise level in dBu (for comparison with the EIN of a pre-amplifier), given the sensitivity of the microphone in dBV/Pa, use this formula:

Noise level (dBu) =
   Equivalent noise level (dB SPL) + Sensitivity (dBV/Pa) − 91.8

(Note that this gives a noise level under the same conditions as the sensitivity figure, e.g. unloaded. Also the same weighting will apply as used for the equivalent noise level − see the next sub-section.)

For example, a microphone with an equivalent noise level of 17 dB SPL and an unloaded sensitivity of −44 dBV/Pa will have an unloaded noise level output of approximately −119 dBu.

Noise Weightings

However, there is another important point to consider. By refererence to the Decibels page, you will understand that sound levels are often measured with a 'weighting', to simulate the intensity of the sound as perceived by an average human ear, with its very frequency-dependent sensitivity. Likewise, the noise output of a microphone must be similarly weighted to give its perceived level. Unfortunately, there are two different weightings that are commonly used for the measurement of microphone noise levels, and they give quite different results:

• The so-called 'A-weighting', which gives a reasonable correspondence to the human ear's response to sound. It's application to microphone noise measurements, although very common (especially in the USA) is however highly questionable at the subjective level, because the ear's response to noise is different to its response to the single sine wave tones on which A-weighting is based. This weighting is defined in the sound level meter standard IEC 61672-1.
• The so-called 'CCIR weighting', or 'ITU weighting' which does not filter the high frequency noise so severely and so gives a higher value of noise level (and a correspondingly lower value of signal-to-noise ratio). It also uses a carefully specified dynamic response to impulsive noise (though that isn't so relevant to microphone noise). This weighting is defined in standard ITU-R 468 (previously known as CCIR 468 or DIN 45405).

The A-weighted figure is the one most often seen (not least because it makes the mic specs look better!). As an approximation, for mic noise measurements the difference between the two figures is about 11 dB. Therefore, an A-weighted noise level of 13 dB would be equivalent to a CCIR weighted noise level of about 24 dB, and an A-weighted signal-to-noise ratio of 67 dB would be equivalent to a CCIR weighted signal-to-noise ratio of around 56 dB. This matter of weighting does not affect the validity of the explanation and calculations given in the preceding sub-section (Types of Noise Specification), except that when using that formula to convert between equivalent noise level and signal-to-noise ratio you must remember that an A-weighted equivalent noise level becomes an A-weighted signal-to-noise ratio, etc. (Of course, if required you can then convert further using the 11 dB difference just explained.)

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Use of Microphones

To get the best results, it is important to choose an appropriate type of mic for the job, and to use it correctly. For guidance on choosing a suitable microphone, see the Microphone Selector. The 'correct' use of microphones is a huge subject in itself, and engineers have their own differing opinions on which techniques give the 'best' results under various different circumstances. Performers (especially vocalists) may also have their own preferred microphone technique, sometimes without realising the effect that this has on the amplified (or recorded) sound (see Microphone Technique on the Getting Started − for Performers page and also the paragraphs below).

One thing that everyone agrees on, though, is that the distance between a microphone and the sound source that it is meant to pick-up is a hugely important factor. This is due to at least three major reasons:

1. Proximity Effect

Most PA mics are uni-directional types, and all uni-directional mics exhibit what is known as the "proximity effect". The result of this effect is that sounds which are made very close to the mic are picked up with a greater bass response than sounds which are made further away. This is most important for presenters and vocalists to understand, because the difference that a change in working distance makes to the sound of their voice can be quite dramatic. It is especially significant for deep-voiced vocalists (usually male), because a greater proportion of their voice is in the frequency range which is subject to the proximity effect. At a working distance of greater than about 4 to 6 inches (10 to 15 cm), the proximity effect can be ignored. As the distance decreases from this down to zero, the amount of bass emphasis increases.

2. Unwanted Pick-up of Ambience, Leakage and Feedback

Just like an ear, a microphone will pick up sounds that originate close to it more readily than sounds that originate further away (simply because of the dispersion of sound − see Inverse square law). Therefore, if a microphone is placed a large distance from the sound source that it is intended to pick up, its electrical output level (resulting from that source) is likely to be very low, and so a large amount of amplification (gain) will have to be applied to the electrical signal that it produces. This same amount of amplification will also be applied to sounds that it was not intended to pick up, such as unwanted room ambience, sounds from other instruments and/or vocals ('leakage'), and sound from the PA speakers (both front-of-house and monitors) which may result in an over-resonant amplified sound or in acoustic feedback.

This problem can be partially addressed by the use of a uni-directional microphone, placed and directed so that its direction of maximum pick-up is towards the wanted sound(s) and its direction(s) of minimum pick-up towards the most troublesome unwanted sounds (see the polar response patterns). Sometimes it can also be partially addressed by the use of equalisation on the picked-up signal, to provide some discrimination in favour of the frequency spectrum of the wanted sound and against that of the unwanted sound(s).

However, the most effective method of controlling the problem of unwanted sound pick-up is usually to place the microphone as close as reasonably possible to the wanted sound source and directed towards it − bearing in mind the proximity effect (see above) and the 'variable distance' factor (see below) − so reducing the amount of amplification that is necessary. Also, where practicable, unwanted sound sources should be kept as far as possible from that microphone and should not be directed towards it.

3. Level Changes With Variable Working Distance

When the distance between a microphone and the sound source that it is intended to pick up is variable, as in the case of most lead vocals microphones, there is another factor to take into account besides the changing proximity effect. This is that the effect on the microphone's ouput level of changing the working distance by a given amount (say, 2 cm) depends on what the distance was to start with. To explain this, we need to consider that the output level increases by 6 dB for every halving in working distance (the inverse square law).

For example, consider a stand microphone that is 4 cm from a vocalist's mouth. If he/she then moves 2 cm closer to the mic then the distance will have been halved so the output level will increase by 6 dB, which is very significant. (In addition, there will of course usually be a considerable change in the proximity effect.) Now compare this with a starting distance of 10 cm, and again reduce that distance by 2 cm. In this case, the working distance will only have been reduced by a factor of 0.8, resulting in a level increase of only about 2 dB from the microphone.

So, it can be seen that a microphone that is very close to a sound source is very sensitive to changes in working distance, while one further away is much less sensitive to such changes. This partly explains why compression is so often used on close-miked lead vocals.

Application

When considering how best to apply this information, it is important to take into account the microphone technique of the vocalist (see Microphone Technique on the Getting Started − for Performers page). Unless there is close supervision, or a physical barrier such as a separately-mounted pop screen (both of which are only likely to apply in a studio setting), the vocalist may at any time choose to vary the working distance between several 10's of cm and zero, as well as varying the loudness of their voice. These variations may be made deliberately, or to some extent unintentionally; in any case the result will be changes in the picked-up vocal level.

Provided that, in the overall sound mix, the combined effect of such changes (taking into account any compression applied) is what the vocalist intended, and provided that the mic pre-amplifier gain is set so as to avoid distortion at the maximum output level that will be obtained from the mic as the changes occur, then all is well.

But otherwise, substantial changes in working distance can be problematic for the sound engineer and so should be avoided. Compression only goes part-way towards addressing this, as it does not compensate for the resulting changes in proximity effect, nor for the increased pick-up of unwanted sounds that occurs when decreased mic output level causes an increase in the gain applied by the compressor (or indeed manually by the sound engineer).

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Care of Microphones

Mics contain delicate precision-engineered components, and if you want your mics to continue to perform as well as when they were new, you must look after them very carefully. Even ruggedised stage mics will benefit from careful treatment. Following these simple do's and don'ts will help considerably:

• DO keep them in padded protective boxes or pouches − preferably individually − when not in use (especially during transport).
• DO clean the integral windshield from time to time, when this is accessible. Follow the maker's instructions (especially for expensive mics!), but in the absence of any instructions the basket (the wire-meshed cover part only) of most types can be unscrewed and then gently washed in warm soapy water − allow to dry thoroughly before re-attaching to the main part of the mic.
• DON'T check them by tapping them or by blowing into them − speak (or sing) into them instead, and educate users to do the same.
• DON'T drop them or allow them to be subjected to other sudden shocks.
• DON'T store them in damp conditions or expose them to extremes of temperature.
• DON'T expose a microphone to sound levels exceeding its specified maximum SPL − at the very least this will give a distorted pick-up of sound and may even damage the microphone.

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Microphone Selector

The purpose of this information is to give you a general guide as to the most popular mics for a given application. As there are hundreds of mics available, from many different manufacturers, it would not be practical to try and list them all. Therefore, only the most popular manufacturers are listed.

If purchasing a UHF radio microphone system that you wish to use in a regulated (i.e. licensed) frequency band in the UK, then be sure to take account of the fact that the previous any-site licensed band (channel 69 and other individually allocated frequencies in the range 790 to 862 MHz) used by older systems became unavailable at the end of 2012. Any-site licensed UHF systems must now operate in channel 38 or in the 823 to 832 MHz band. For further details see Wired or Radio.

Note that some mics are designed for a very specific use, whilst others are of more general application. It doesn't follow that just because a mic is very expensive that it must be either very specific in application, or that it must be very general purpose! Neither does it follow that just because a mic is very specific in application, or very general purpose, that it must provide very high performance. As circumstances vary from use to use, before buying a particular mic it is usually advisable to check with the supplier that it is a good choice for your particular situation.

The listed microphones are arranged in 'price bands' according to the table below. These bands are intended to give an approximate guide as to what you might actually pay on-line (not the manufacturer's R.R.P., which is generally considerably higher); the figures include UK VAT at 20%. (In the Microphone Details table that follows the selector table, where a pair of bands are quoted this indicates that the mic is priced close to the boundary between those bands.) Actual prices may vary significantly from supplier to supplier and can change from week to week − it definitely pays to shop around. Some of the listed mics are no longer being manufactured, but may be available to purchase second-hand.

Remember though, when buying to a tight budget, that you get what you pay for and, in general, the price band shown for each mic can be taken as a rough guide to the quality to be expected − when comparing like with like. However, note that some users may prefer the sound (or other characteristics) of particular mics, as compared to more expensive models. Note also that mics that are listed for the same application may not be directly comparable − e.g. some may be large stand-mounted types while others may be miniature clip-on types, and such factors can also influence the price. Sorry, these mics are not on sale from PAforMusic.

The currency conversions used in the table below are only a very approximate guide, as conversion rates are constantly changing.

Price band    (pb)	£ (GBP)	Euros	$ (USD)
A	< 80	< 90	< 100
B	80 − 115	90 − 130	100 − 145
C	120 − 150	135 − 165	150 − 185
D	155 − 190	175 − 210	195 − 235
E	195 − 245	220 − 275	245 − 305
F	250 − 340	280 − 380	310 − 425
G	345 − 485	385 − 545	430 − 605
H	490 − 895	550 − 1000	615 − 1120
J	900 − 1995	1005 − 2235	1125 − 2495
K	> 2000	> 2240	> 2500

For more detailed information about the listed mics, click on or tap the mic's model number to jump to the relevant entry in the Microphone Details table, which follows the selection table (currently only operative for wired mics). To return to the price-band table, click on 'pb' in the table headers.

More mics are added to this selector from time to time.

To see the full width of the tables, you may need to increase the width of your browser window or select a smaller text size (in Explorer, View→Text Size).

Mics are listed for the following applications:

Lead vocals (wired)
Lead vocals (radio)
Backing vocals (wired)
Backline (not bass)
Bass backline
Snare & Toms
Kick drum
Hi-hats & Cymbals
Drum overheads
Piano
Brass & Woodwind
Acoustic Strings
Rifle
Floor
Lectern
Choir
Lavalier (wired)
Lavalier (radio)
Headset (wired)
Headset (radio)
Studio

• Dynamic mics are listed in black
• Condenser mics in red.
• Omni, super-cardioid, hyper-cardioid, rifle and switchable pattern types are listed in italics (most other types are cardioid).
• Types with multiple elements of mixed design or pattern are listed in magenta.
• '+' on the end of a model number stands in place of suffix letter(s) or number(s) identifying 'sub-types', and indicates that more than one of such sub-types may be suitable for the application concerned.

Back to: Lead vocals (wired)
Lead vocals (radio)
Backing vocals (wired)
Backline (not bass)
Bass backline
Snare & Toms
Kick drum
Hi-hats & Cymbals
Drum overheads
Piano
Brass & Woodwind
Acoustic Strings
Rifle
Floor
Lectern
Choir
Lavalier (wired)
Lavalier (radio)
Headset (wired)
Headset (radio)
Studio

Microphone Details

The table below provides more detailed information on the wired mics listed above, listed alphanumerically under each manufacturer. 294 microphones are listed. This table allows you to readily compare the specifications of many different models. Unfortunately not all the details can currently be given for all the mics, but will this will be rectified when possible. Remember that specifications usually give nominal, not limiting, values, therefore the figures for any particular specimen may be higher or lower than the figures given. Limiting values are indicated with < or > symbols.

You are reminded that no responsibility is accepted for any errors in this information − please confirm suitability before making your purchase. If you require further information, click on the link to the appropriate manufacturer's website.

The same notes on prices apply as were given at the start of this section, except that where two price bands are given (e.g. 'DE') the mic is priced close to the boundary between those bands. To return to the price-band table, click on 'Price band' in the table headers. Some of the listed mics are no longer being manufactured, but may be available to purchase second-hand.

To see the full width of the table, you may need to increase the width of your browser window or select a smaller text size (in Explorer, View→Text Size).

Key to physical design ('Phy' column):

Tap:	Classic full-size design, generally having a basket of larger diameter than the mic body. Most, but not all, have a tapered body. Suitable for hand-held use (if appropriate) or on a stand.
Cyl:	Cylindrical design (generally slim), of similar diameter along its whole length. Usually for stand use.
Ins:	Equipped with an integral means (usually a clip, a clamp or an adhesive surface) for direct attachment to an instrument.
Min:	Miniature (e.g. short-bodied) design for compact access to instruments (esp. drums) when used with a stand. Some types screw directly onto the stand.
Bnd:	Boundary type intended to be placed on or fixed to a surface (or with a plate incorporated).
Lav:	Lavalier.
Hst:	Headset.
Gnk:	Gooseneck.
SA:	Side-addressed types, e.g. classic large-diameter studio-style designs (typically used with a suspension mount) and 'rectangular' (flat-sided) designs.
Oth:	None of the above (includes capsules and most kick drum mics).

A more specific indication of the physical shape is provided (in most cases) by a small image that appears when hovering your mouse over, or tapping on, the relevant Phy column entry.

Key to element types ('Elem' column):

Dyn:	Dynamic (coil)
Rib:	Dynamic (ribbon)
Con:	Condenser
Mul:	Incorporates multiple element types

Key to polar patterns ('PP' column):

Om:	Omnidirectional
Cd:	Cardioid
Sc:	Super-cardioid
Hc:	Hyper-cardioid
Sh:	Shotgun (= rifle = lobar)
F8:	Figure-of-8 (= bi-directional)
Sw:	Switchable (or all available patterns are listed)
N/A:	Not applicable (e.g. for contact pick-ups)

As with all the values listed, the frequency response figures given are those quoted by the manufacturer. For most types of microphone, these figures must be treated with extreme caution because:

• There are inconsistencies in the way they are arrived at − particularly as regards the amount of loss in response that is obtained at the quoted figures (compare cut-off frequency), and as regards the distance from the microphone at which the response is measured (see proximity effect).
• The response of many types of microphones is not flat between the two quoted frequencies, but exhibits very significant peaks and/or troughs − often introduced intentionally. (This is in contrast to the situation with speakers, which are generally designed with the aim of a flat response across their intended frequency range.) Such intentional variations are a major factor in the suitability (or otherwise) of particular mics for particular applications, for example a "presence peak" is commonly designed into the response of vocal mics.

Therefore, the quoted frequency response figures should in the first instance be taken only as a rough guide. For clarification of the response provided by a particular model of microphone, it is best to consult the manufacturer's frequency response graph for the model concerned.

Sensitivities are generally quoted under open-circuit (no load) conditions. Max SPL figures are generally quoted at 1% THD (blue figures at 0.5% or less), and impedance figures at 1 kHz.

Outputs are balanced unless indicated otherwise.

For ease of comparison, all noise levels are given as A-weighted equivalent noise levels (sometimes referred to as 'self noise'). Where the manufacturer's specification indicated the noise in a different form (e.g.CCIR weighted or as a signal-to-noise ratio), their figure has been converted to an A-weighted equivalent noise level and is marked here with an asterisk. Note that noise levels are not usually specified for dynamic mics.

A selection of mics are listed for the following manufacturers; the links take you to the relevant section of the list.

AKG
AMG (C-ducer)
Audio-Technica
Audix
Behringer
Beyer-Dynamic
Neumann
Rode
Samson
sE Electronics
Sennheiser
Shure

Please let me know if there are other specific mics that you feel would be usefully added to this list.

To see a small image of a mic, just hover your mouse over the bold 'Phy' column entry for the relevant mic. (Sorry, images are not yet available for all the mics listed.) The image will appear below that point, so may not be visible if you are near the bottom edge of the window. Image credits are to the relevant manufacturer.

* See the note on noise level at the top of the table.

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This page last updated 12-Jul-2019.