What Does The Damn Thing Actually Do And How Does This All Work? – Part 4: Microphones And Mic Accessories

This is part 4 of our series of blog posts with simple explanations for the most common terms in audio, as well as features and functions found on recording studio equipment. The resource to end the confusion and help you focus on creating amazing music!

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Fellow audio nerds, please note:

The explanations are as non-technical and simple, as possible. I want it to be practical and useful and I don’t care if everything is 100% scientifically correct. All that matters to me are the results that the people who read this will hopefully get.

It’s not meant to be an academic piece of work on audio technology and if you are an experienced engineer who thinks this is stupid, then I’m really sorry, but this is not for you then. And I can definitely understand your desire for accuracy and your love for nerdy discussions, because I’m a total freak in this regard, myself (just ask my wife). I just think inflating our egos by throwing around complicated terms and definitions is not going to help anyone trying to capture a great song.

Microphones And Mic Accessories

Different Microphone Types

Dynamic Microphones

Dynamic mics can usually handle high sound pressure levels (volume) without distorting and they are most often used for loud acoustic instruments (like drums), or for capturing guitar cabinets. They usually don’t sound as detailed as condenser or ribbon microphones and have a higher noise floor (more hum and hiss), especially compared to condenser microphones. They don’t break as easily as condenser or ribbon mics and they usually won’t be damaged if you turn on 48V phantom power, although they don’t need any phantom power to work.

Condenser Microphones

Condenser microphones are more sensitive than dynamic mics. They capture details better and have a lower noise floor (less hum and hiss). But some of them can’t handle high sound pressure levels very well, they are more likely to break and for some instruments or voices they can be even too detailed, especially in the high frequencies. They are typically used for vocals, drum overhead mics, hi-hats, or quiet acoustic instruments, like acoustic guitar, piano or strings. 

They require 48V “phantom power” to work. This is because they have an active component in their circuit, that requires external power. The 48V phantom power gets to the mic via the standard XLR microphone cable. It can be switched on and off on most of the common interfaces and mic preamps. Some condenser mics can also be used with batteries instead of power through the cable and there are tube condenser microphones that have their own power supply and get the required power from there.Condenser microphones come in two main categories: 

1. Large Diaphragm (LDC)

Those are the big studio mics you typically see in front of a singer. They have a very low noise floor (almost no hum and hiss) and often color the sound in a certain (hopefully pleasant) way. 

2. Small Diaphragm (SDC)

Those are the small, “pen-like” microphones you often see as overhead mics, or in front of an acoustic guitar. They are a bit noisier (more hum and hiss) than Large Diaphragm condensers, but also a little “quicker” and more detailed sounding. That means transients and high frequencies are captured a bit more accurately. 

Ribbon Microphones

Ribbon microphones usually sound darker and “fuller” than condenser mics and some dynamic mics. But they sound very detailed and respond quickly to transients. So, if a condenser is too bright or thin, but you want the details and “resolution”, a ribbon might be a great choice. They can also sound pretty “vibey” and color the sound quite a lot, so they can be used to add character.

They usually have a “figure of 8” polar pattern, which means they are sensitive for sounds coming from the front and back, but reject sounds coming from the sides. That means they pick up quite a bit of room sound (through the back), but are great for isolating stuff next to them. They usually also have a strong proximity effect. That means the closer you get to the mic, the more it pronounces low frequencies (bass). Putting a ribbon very close in front of a guitar amp, for example, can lead to massive (and often overpowering) bass response and a rather dark tone. This can be great (especially when combined with other mics) or absolutely terrible and “muddy” or “woofy”.

Ribbons have been known as typical vintage mics and didn’t get as much use in home studios for quite some time (also because they were pretty expensive) but they became very popular again and now there are various cheap or at least affordable ribbon mics on the market that actually sound pretty cool. Many people love them on guitar amps or as drum overheads, because they capture all the detail, without sounding harsh. Ribbon mics break pretty easily, so you have to handle them with care. And they can break when accidently used with 48V phantom power. So always double check if phantom power is really switched off before plugging in a ribbon mic. 

Polar Patterns

The polar pattern of a mic describes how the mic captures or rejects sounds from different directions, meaning how sensitive it is to sound coming from the front, back and sides. Some mics have multiple, switchable polar patterns, making them very versatile.

Cardioid

A Cardioid mic accurately captures sound coming right from the front, straight into the mic. It gets quieter and less accurate if the sound is coming from the sides and very quiet/inaccurate if the sound is coming from the back. By “inaccurate” I mean it could be thinner, darker, brighter, etc. compared to what’s captured in front of the mic. Most cardioid mics have a noticeable, but more moderate proximity effect than figure of 8 mics. Cardioid is the most common and widely used polar pattern. Almost every dynamic mic (with a few exceptions) has either a cardioid or hyper-/super-cardioid pattern.

Hyper-/Super-Cardioid

These are similar to a cardioid pattern, but more narrow. Sound from the sides is rejected better and the “sweet spot” in front of the mic is smaller. But it’s a little more sensitive to sound coming straight 180° from the back of the mic. The maximum rejection is not straight in the back, but slightly off to the sides. Most hyper- or super-cardioid mics have a noticeable, but more moderate proximity effect than figure of 8 mics. 

Figure Of 8

These mics capture sound coming straight from the front and back, but reject sound coming from the sides. Most ribbon mics work that way. It’s great for isolating stuff on the sides, but picks up quite a bit of room sound/reflections through the back. Most figure of 8 mics have a very strong proximity effect. 

Omnidirectional

These mics capture sounds coming from any direction at almost equal volume and almost equally accurate. There may be subtle differences, but it’s pretty much the same from every direction. They don’t have any proximity effect at all. Measurement mics are usually omnidirectional, for example.

Stereo Miking

Stereo miking means capturing the same sound source with two microphones and then placing them left and right in the mix. So that the result is a (more or less) accurate stereo “picture”, similar to what we hear with our two ears. To be a “true” stereo recording it’s not enough to just throw two mics at a source, because that can cause all kinds of problems, or it can at least be far from what you would call an accurate stereo picture. There are different miking techniques, that you can use to capture a stereo recording:

XY 

Two cardioid mics positioned at right angle (90°) with the capsules aligned (as close together, as possible). Result: clear, accurate and rather narrow stereo image. Minimal (pretty much zero) phase issues.

ORTF

Two cardioid mics positioned 17cm (6.7″) apart and at a 110-degree angle.Result: Wider than XY, but still pretty little phase problems and a pretty solid center of the image

AB

Two microphones placed further away from each other to cover a greater space or create a wider stereo image, but without running into serious phase problems. Although there will always be issues when you use a spaced pair of mics for the same source, because the sound reaches the mics at different times. But a way to minimize those problems is the “3:1 (three to one) rule”. It means placing the mics three times as far apart as either one is to the closest sound source in the area they are covering. For example, if one mic is 2″ (60cm) above the cymbals of a drum kit, try placing them 6″ (180cm) apart from each other.

Blumlein 

Blumlein is very similar to XY, but with greater stereo separation, resulting in a wider stereo image. It’s two figure of 8 microphones positioned at right angle (90°) with the capsules aligned (as close together, as possible). It’s as accurate as XY, but due to the strong side rejection of the figure of 8 pattern, it sounds wider and let’s you capture a really beautiful stereo image. It also gives you control over the amount of ambience (room) that you want to capture. The back of the figure of 8 mics picks up quite a lot of room sound and depending on the distance to the source and the back wall, you can kind of “mix” it with the direct signal from the source. Close to the source with enough distance to the back wall: Pure stereo with very little ambience. And vice versa. 

Switches Often Found On Microphones

Pad 

Reduces the input or output volume by a certain amount (-10dB, -20dB, etc.) to avoid clipping (distortion). Can be found on interfaces, microphones, preamps, line outputs, or DI boxes

48V

Turns 48 Volts “phantom power” on and off on a microphone preamp (mic input on an interface or console). This is required for condenser microphones to function. They only work with 48V phantom power. The 48V phantom power gets to the mic via the standard XLR microphone cable. No additional power cable required. If you use a dynamic mic, you don’t need phantom power, so it’s best to just turn it off. If you use a ribbon mic, you should absolutely turn 48V phantom power off, because it can damage the microphone.

Low Cut (High Pass)

This changes the frequency response of the microphone or other piece of gear. Meaning it filters out certain frequencies. A “low cut”, for example, filters out the low frequencies (bass) to avoid rumble, reduce hum, or just make a signal les “woofy” or “boomy”. It’s also called “high pass” sometimes. So this is the same thing. It “cuts the lows”, or “let’s the highs pass through”, depending on how you look at it. There are be other switches that do similar things, such as “high cut” (“low pass”), or “shape” (often a boost or cut in the mid frequencies)

Mic Accessories

Pop Filter

This is a thing you put in front of the mic to prevent plosive sounds, like “p”, from becoming overly loud and possibly causing distortion in the microphone.

Cloudlifter/Fethead

This is a little device that you plug between your mic and mic preamp (mic input on an interface or console) that boosts quiet microphones, like some dynamic or ribbon mics. This reduces noise (hiss) and prevents you from having to turn the gain on the preamp all the way up.

Shockmount

This is a “flexible microphone clamp”, that holds the mic and isolates it from impact sounds, like stomping on the ground.

Windscreen

This is the (mostly foam) stuff you can put over most microphones, if you want to use them outside. It protects the mic from capturing wind noise or distorting from it. Some mics have built in windscreens. Windscreens make the mic sound darker and less detailed. So if you’re not outside in a windy location, it’s probably best to not use them.


These are the other posts in this series:

  • General Audio Terms

  • The Production Process

  • Routing And Processing

  • Preamps, Converters, Interfaces

  • ​Cables and Connectors

  • Computer, Software And Audio Files

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