The AKG D202 and later D222 was probably the first commercial microphone to use dual diaphragms to minimize the proximity effect of a cardioid mic. The mic had a very effective sintered bronze pop filter, exclusive to AKG, that also protected the capsule from dust and spittle. I believe it was first produced in the late 1960's. Coutant.org has an excellent page describing this vintage microphone. AKG discontinued this mic around 1980, but there was such demand for its performance that they added it back to their catalog, at least for a time, but it is no longer available from AKG, now part of JBL. Some are available from sources such as Ebay.

Another vintage mic that had the AKG sintered bronze pop filter was the D1000E. Numerous versions of the mic were sold, dating as far back as 1967. I actually used some of these in the 70's. It was a good-sounding mic with a moderate proximity effect and three frequency response settings. Recording Hacks has some information about the mic. It can still be found on sites like Reverb.com or Ebay.

Microphones are used in any application where it is necessary to amplify or record a sound source. Any type of microphone can be used in most cases, but in general, a microphone is selected based on the nature of the sound source and the characteristics of a particular microphone. This picture to the right is the microphone array inside an Alexa Echo. It consists of 7 small condenser microphones (MEMS) in a circular beam-forming array that uses Amazon’s proprietary software for wake word recognition, beam-forming, noise reduction, and echo cancellation.

For a given application, there are general preferences or recommendations that may apply, but there are exceptions to almost every rule one might employ. That is why it is so important to understand the various types and characteristics of microphones. Generally, applications fall into these categories:

Vocals -This tends to be a situation fraught with personal preferences, from the viewpoint of both the performers and the audio techs. The audio tech may strive for an accurate frequency response and use pop filters to minimize plosives, while the performer wants a mic that gives them the type of sound they prefer, one that emphasizes the good part of their voice and helps correct whatever deficiencies might exist. Some examples: A baritone tends to prefer a microphone that has appreciable proximity effect, because it adds low-frequency richness to his voice. This usually means a dynamic mic that is used close to the mouth, and they may not object to the use of a foam pop filter to minimize plosives. A tenor, or a female, tends to prefer a mic that has more high-frequency content, so they tend to object to a pop filter, either because they feel it reduces the high frequency harmonics of their voice, or, for a female, it hides too much of their face.

Many amateur vocalists and audio techs think a mic should always be used as close to their lips as possible, because that's what they generally see professional performers do. They fail to understand that in most situations, these performers are in a very loud environment, and many have fairly weak voices, so it is important that they get as much volume from their mic as possible. Moreover, these same professionals may prefer a particular microphone that has a low output level and they may object to pop filters. Because of the high sound levels generally used, the various plosive and mouth noises, that result are buried in the noise. There is usually a professional engineer manning the mixer who can apply compression and make other adjustments needed to compensate for the environment.

In other environments, such as a church, the ambiance is quite different, and miking techniques should be used that give a more natural sound. This calls for the use of pop filters to minimize plosives, a varying of mic distance to help correct for vocal differences across the frequency range, and lower overall sound levels to emphasize communication and worship. See the video to the right Tips for Singing Into a Microphone for more details.

In a recording studio, pop filters are generally used to avoid plosives, and the vocalist is some distance away, unless the proximity effect is desired.

Distance is a critical factor in using microphones. Not only is the proximity effect a consideration, but the sound pressure level (SPL) at the microphone goes as the inverse square of the distance to the source. This means that if the distance is cut in half, the SPL goes up four times. Thus, a bass vocalist can increase his output substantially by getting the mic as close as possible to his mouth, boosting both the bass content (proximity effect) and the level substantially (distance factor).

When a vocalist reaches a point where their vocal level is low -typically in the lower registers - bringing the mic closer to the mouth will help keep the volume up. When a vocalist reaches the most powerful output range, he/she can move the mic away somewhat to keep the volume more even. This means that the singer must keep the microphone at a suitable distance away from the mouth most of the time so that the distance can be varied as needed. "A singer can get a deep, earthy sound by singing very close, then change to a more penetrating sound by singing louder while moving the microphone away. This kind of creative use takes some practice, but is very effective. " (Audio Technica web site)

Despite what many people say, a mic generally should NOT be kept as close to the mouth as possible, unless the situation calls for this. However, since distance is such a critical factor, it's important that a speaker or singer learn how to maintain a consistent spacing and change it only as needed to compensate for vocal intensity. The female singer to the right is using a pop filter and holding the mic above her mouth. Both techniques help to minimize plosives and sibilance.

Public Speaking - Microphone selection and placement are important for public speaking. Generally, a directional mic is used to minimize pickup of environmental sounds behind the mic A foam pop filter should be used to minimize wind noise and plosives. Two special types that are often used are the Lapel and the Head-worn types. A lapel is somewhat simpler to use, but it requires that the mic be six or more inches from the mouth. This is fine when the environment is fairly quiet, such as in a studio or worship service. An omnidirectional type is less sensitive to position, but a cardioid pattern helps reduce environmental pickup.

Another type that has become quite popular in recent years is the Headworn microphone, These may be a true head-worn style that clips over both ears, but can be an ear-worn style that clips over one ear. These are available as omnidirectional and cardioid types. The primary advantage is that it enables the mic element to be placed closer to the mouth. It is important that the mic not be directly in front of the mouth, as these are very sensitive to plosives. The mic element should be to the side of the mouth. In theatrical productions, it is sometimes helpful to place the mic element at the performer's hairline, either at the ear or the forehead, if it is a lapel type.

Instruments - To some extent, the particular type of instrument is a consideration. In general, condensers are preferred because of their sensitivity, their relatively smooth and wide frequency response. This is particularly true for drums, strings and horns in the mid to high frequency ranges. Condensers are great for picking up the high frequencies and transients drums generate, but their sensitivity can result in signal bleed from other sound sources nearby. Heil, as an example, has developed a dynamic mic, the PR 30, that is very effective with drums. For bass instruments, dynamic mics are often used, placed close to the sound source. For example, the Shure SM57 is a standard for miking guitar amp speakers, and dynamics are often used for kick drums. TheSM57 can take high sound pressure levels, it's proximity effect adds to the bass level, and the mic screen design allows the capsule to be very close to the device.. For a string bass, a condenser usually works better than a dynamic, as it can be used a bit farther away, thus picking up more of the overall character of the instrument.

A lot depends on the environment. In a studio, you can place the mic anywhere you want. In a live situation, it depends on how loud the sounds are around the guitar or amp. Closer placement with the mic will decrease pickup of other sounds but with a directional mic will also increase the bass frequencies. Select the More Information tab for additional information about miking instruments.

A special clamp allows use of a Royer ribbon mic and a Shure SM57 close to each other. This combo will be placed in front of the amplifier in a position selected to give the type of sound preferred - brighter vs more bass. Be sure that the mic does not contact the speaker itself or the grill cloth.

Distant Pickup -

This applies to large vocal groups or perhaps the distant sound of a band or performance, as well as to podium or conference table miking. For this type of application, a condenser microphone is the first choice, and generally a more directional mic is preferred. Sound pressure levels are much lower in most distant applications, and a condenser is more sensitive than the other mic types. When picking up a group, the microphones should be placed so as to minimize the difference in distance among the singers, and multiple mics should observe the rule that the mics should be three feet apart for each foot of distance to the source to minimize phase interference, When it isn't possible or practical to hang a mic, there are several long-boom mics than can be used.

DPA has an excellent guide for miking groups.

Hypercardioid and supercardioid mics are somewhat more directional than cardioid mics and should be considered when miking from a distance. For longer distances, and when ambient sounds are present that need to be minimized, a highly-directional, shot-gun type is called for, and in some cases a mic can be used with a parabolic reflector to help focus sound on the capsule.

Special Purpose -

There are some situations for which a particular type of mic has been designed or is called for. One such type is the boundary mic. This is usually a condenser mic placed on a surface which helps direct more sound to the mic element. Situations such as a podium, a conference table, or a theatrical production might call for such a mic, and most of the major mic manufacturers make them. In some situations, a dynamic mic can be placed near a surface to use this effect. A good 2021 overview of boundary mics and automixers can be found at SVCOnline.com.

For stereo sound, at least two mics are needed. They can be spaced apart 3 feet or more, depending on the situation, or directional mics can be placed in a Blumlein alignment where they are perpendicular to each other. Also called ax XY arrangements, this type of mic is available for small digital recorders, as as shown to the right .

Another type of mic that is becoming popular is the microphone array. These are used in conference rooms or area monitoring situations, and a popular home automation device, the Amazon Echo, uses this technique with 7 microphones. For examples, check out some Shure Arrays and the Acoustic Magic Voice Tracker.

A most unusual application is the DPA microphone that is now on the surface of Mars.

The Shure MXA310 Array Microphone

Shure offers the following basic rules for using microphones. These are general guidelines - the guidance given above should be considered in applying these general rules.

General Rules for Use

• Aim the microphone toward the desired sound source (such as the talker, singer, or instrument) and away from unwanted sources.
• Place the microphone as close as practical to the desired sound source.
• Work close to the microphone for extra bass response.
• Use only one microphone to pick up a single sound source.
• Use the fewest number of microphones as practical.
• Keep the distance between microphones at least three times the distance from each microphone to its source.
• Place microphones as far as possible from reflective surfaces.
• Add a windscreen when using the microphone outdoors.
• Avoid excessive handling to minimize pickup of mechanical noise and vibration.
• Do not cover any part of the microphone grille with your hand, as this will adversely affect microphone performance.

Sweetwater has an excellent article where a good vocalist gives guidance for use of a microphone. He has some great suggestions. Unfortunately, his presentation is marred by plosives because he uses an SM58 without a pop filter. A perfect demonstration as to why a pop filter is so important for vocalists.

How NOT to use a microphone

Ales Stephanic published an article in 2022 that suggests ways in which a vocalist can help their sound engineer by following some simple suggestions, such as not cupping a directional mic.