User:11090/Microphone Technique

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If you have arrived at this page, you likely want to know how to get more out of your auditory capture device so that your listeners can admire the smoothness of your dulcet tones.

Types of Microphone

This is one of the most important ones in terms of handling and address. The Shure SM58 dynamic mic can be, (and from the look of some of ours, has been) dropped out of a helicopter and still used for a respectable gig at the other end. However there are some high-end ribbon mics used for voice over that you can damage simply by shouting at them.

Dynamic Microphones

These microphones are some of the more common around and are at the time of writing used by URY in our studios with our SM7Bs and in OBs with our SM58 microphones. They work due to an induction coil attached to the diaphragm moving in response to changes in sound pressure within a magnetic field, this generates a current proportional to the original noise.

Advantages

• Better rejection of background noise
• Usually has more directional pickup pattern
• Does not require Phantom Power
• Less sensitive to physical handling

Disadvantages

• Non-uniform frequency response
• Struggles with far away sounds

Condenser Microphones

Condenser microphones work through two thin metallic plates with a potential difference between them forming a capacitor, one of these plates acts as a diaphragm to vibrate in sympathy with sound waves like the human ear drum. As the diaphragm vibrates it changes the distance between itself and the other plate, thus creating a current which is a representation of the original sound.

Advantages

• Generally more accurate representation of original sound
• Cover larger frequency range
• Can pick up sounds from further away, including groups of people

Disadvantages

• Picks up large amounts of background noise, even noise that you can't hear, such as low frequency rumblings through walls.
• Receptive to handling noise, if you grab or knock your microphone while using it, it will be very loud and noticeable.
• Require phantom power in order to operate, the microphone can be damaged if this is not done properly.

Ribbon Microphones

Ribbon Microphones were some of the earliest microphones used in a broadcasting context. They are quite rare to see these days outside of specialist music studios and orchestral concert recordings, but they are still produced, and can be found in a number of applications if you're into this sort of stuff.

Advantages

• They can produce a very nice coloured sound, reminiscent of the golden days of radio... if you're into that...
• They have a figure 8 pickup pattern with excellent noise rejection to the sides, this means they make a very good stereo microphone when used in pairs. This is useful to know exactly non of the time to you, but is very important for things like concert orchestra recordings.

Disadvantages

• They break *very* easily, like you don't even need to drop them, just give them a hard knock.
• They're usually very expensive, and if they're not, they're usually very crap.

Pickup Patterns

Microphones are in general directional. This is important to bear in mind while using them. You will always want the zone of the microphone that picks up the most noise directed towards the source of the sound that you want to record, (in this case, your voice). This is very important to bear in mind when you are doing your shows, you don't need to rigidly sit in the exact same spot but if your microphone is designed to only pick up things directly in front of it it is very easy to slowly drift out of this cone without noticing, especially when you are in the middle of a long link. One good tactic to deal with directional microphones in a home environment is either to keep a chair in a fixed position that you have already checked for good pickup, or if you are especially excitable, to keep your no-dominant hand on a desk in front of the microphone throughout the broadcast. If you practice doing this for a while you will get used to constraining your movement to within a certain cone where the microphone is at the right angle and distance to yourself.

• Polar pattern omnidirectional.svg

  Omnidirectional
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  Bi-directional or Figure of 8
• Polar pattern subcardioid.svg

  Subcardioid
• Polar pattern cardioid.svg

  Cardioid
• Polar pattern hypercardioid.svg

  Hypercardioid
• Polar pattern supercardioid.svg

  Supercardioid
• Polar pattern directional.svg

  Shotgun

Microphone Mounts

Microphone Arms

One simple way to keep a microphone at the right distance and relative positioning to yourself is to use a mic arm like the ones we have in the studio. These can seem excessive, and certainly will increase the bulkiness of your setup as compared to a laptop and a desktop microphone. However they contribute to your final product by aiding a more natural delivery of your speech from a comfortable position and making it much easier to move the microphone to a good position.

Buying a mic arm and making yourself a small, vocal environment does not need to be complex or expensive. Cheap microphone arms that clamp to the edge of desks and use a standard 1/4" thread mount can be found on amazon for below £12.

Shock Mounts

Certain microphones react badly to being knocked or held while being used, particularly condenser and ribbon microphones, even when on the ends of a microphone arm or a headset. In order to prevent the nasty knocks and scrapes associated with handling being picked up in the final result on air the microphone must be isolated from the sources of these noises, a microphone connected rigidly to a desk receiving hard knocks will pick up the noises almost as well as if they were made to the microphone itself. This is why it is important to remove sources of vibrations and other external noise from your environment before recording.

One way of avoiding these handling noises is to use a shock mount, these suspend the microphone away from vibration conducting surfaces using elastic cords and a pair of elastic disks. It is important to ensure that once you have installed the shock mount, you only use it to move the microphone, and do not touch the microphone itself. Normally, dynamic microphones do not need shock mounts.

Headset Microphones

Headset microphones are mounted on to a pair of headphones or earbuds, usually in a position that makes them closer to the mouth of the user. They often come cheap or free with modern headphones as they are an integral part of the noise cancelling system. Having the microphone physically attached to the user is a great way of making sure they don't move to far from the microphone. They can be dynamic or condenser, with most consumer earbud microphones being electret condensers.

Positioning

When placing microphones the no.1 thing to consider is the position of the source that you are recording. Knowing the pickup pattern of your microphone, you want to be certain that the thing you want to record (i.e your voice) is in the centre of the zone that gets picked-up the easiest while ensuring that it is pointed away from any sources of background noise or reflective surfaces such as tiles or glass. A presenter must be kept at a comfortable distance from the microphone, and then processing set from that point, the human ear can very quickly get used to poor quality audio containing background artifacts or noise, but if the presenter is swaying backwards and forwards away from their sensitive microphone, this will rapidly distract the listener from the topic of conversation.

Speaking of room positioning, you want to be aware of what you voice will be bouncing off of in the room, as it can very easily go back into the microphone a second time and become distracting to listeners. You can prevent this either though personal positioning, placing the microphone in an area where the sound wave of your voice will dissipate and fragment before being picked up a second time i.e having the microphone and presenter in the middle of a room not in proximity to walls that can immediately reflect audio. Another way of preventing it is through soundproofing, this can be very simple, hanging a soft blanket on a wall on the opposite side of the microphone to the sound source can dampen reflective waves from the initial noise source, and is not difficult to do with sufficient amount of duct tape or some bed slats.

Windshields

When broadcasting outdoors (or even indoors in larger rooms subject to rising drafts), your microphones will pick up the sound of wind passing by and running over their edged surfaces as a low frequency rumble, this can be highly annoying and can making it impossible to hear the intended content. To combat this, windshields are used. They can be several times larger than the microphone and if they are 'hairy' will often be termed 'dead cats/kittens' depending on their size due to their fluffy nature and habit of being attacked by birds when walking in the open.

'Plosives

Plop, Pancake, Pizza, Poke, Pan, Pop....

Say that to yourself, the hard 'P' noise at the beginning of the word is called a 'Plosive. This is because it is a very loud low frequency noise at the beginning of the word, your human ape ears have gotten used to this, and you won't notice it often but compared to all noises you make in pronouncing a sentence, this will usually be the loudest, and your listeners don't necessarily need bleeding ears to enjoy your show.

It is however quite easy to mitigate plosives through three methods:

1. A pop shield, these have two layers of fine fabric close to each other that will reduce the amount of transmitted sound pressure, but not the frequency distribution or general vibration of the noise. You can make them from a crochet hoop and a pair of old tights!

2. A big mic muff, you can buy these for cheap of amazon, and so long as they are made out of a good kind of foam they will attenuate loud plosives admirably.

3. Complicated processing shit™, plosives are louder and bassier than their environment, often focused at 100Hz, if you are willing to mess around with multiband compressors, you can usually deal with them. Don't.... it's not worth it.

Sibilance

Slithering sounds of sonorous symphonies.

That 'esss' sound is sibilance, it's annoying. Really annoying, it cuts through and hurts your ears. Worse there is no physical way of getting rid of it :/ . So you have 2 choices:

a. Get a de-esser and calibrate it towards where your specific sibilance frequencies are to be found. Annoyingly they are different for each person, and in quite distinctly different groups depending on if a person as a traditionally male or female voice. Mine is at 8Khz, which is towards the high end, but yours will be different, you can find yours by using a multiband analyser, and seeing what frequencies you produce when saying sibilant words, then using hardware or software, process it out. This is difficult, and wholly unnecessary, which is why only ArseholesRadio 3 and ClassicFM still invest in the technology to have individual processing for each presenter that tackles these noises.

b. Keep what your mouth is doing in mind as you say the sentence at the top of the section. Instead of curling your tongue to make the hissing noise through a small gap in your mouth, make a concious effort to force your tongue down. This will result in a softer more rolling ess sound, that won't hurt your listeners to hear. This is difficult to do at first, but after a few hours, it's pretty easy to get into. After my first term doing radio my mum noticed how much softer my voice was as a result.

Proximity Effect

As you get closer to a microphone, a thing called proximity effect occurs. This results in your voice sounding deeper and more rumbly. Some people like this and will use it for accentuation. Musicians with proper vocal training in particular can make great use of this effect in order to add more character to the song. In general though, it is to be avoided, as unless you sound like it all the time listeners may be distracted by the difference between your 'broadcast' and natural voice.

Preamps

A microphone preamplifier is a sound engineering device that prepares a microphone signal to be processed by other equipment. Microphone signals are usually too weak to be transmitted to units such as mixing consoles and recording devices with adequate quality. Preamplifiers increase a microphone signal to line level (i.e. the level of signal strength required by such devices) by providing stable gain while preventing induced noise that would otherwise distort the signal. Items like consumer headphone mics and laptop mics will handle this for you, but all pro broadcast microphones will require a device like this. A preamplifier might add coloration by adding a different characteristic than the audio mixer's built-in preamplifiers. Some microphones, for example condensers, should be used in conjunction with an impedance matching preamplifier to function properly.

Low-End Roll-off

In a room without proper soundproofing, low frequency rumbles may be transmitted through walls or normally noise dampening materials, and can make the noise picked up by the microphone sound muddy. Often, humans can not hear these noises, but they still have an effect by reducing the 'headroom' (range between nominal silence and the most powerful signal that can be accurately represented). Ideally to stop this, these low frequencies should be eliminated as early on in the chain as possible. If your microphone or preamp has a low-freq rolloff button or switch it will nearly always be worth using them in order to create the best quality vocals for your show.

Levels and why we sosig

There are any number of things that can increase or decrease your relative volume to the listener. We have loudness standards for making sure that the audio content produced sounds about right to the end listeners. However any number of reasons including changes in positioning or even atmospheric changes in a room can make the produced audio sound off as the output from the microphone varies in volume across a wide range. This range is called the headroom of the microphone, the difference between the quietest sound it can accurately represent to the loudest, before it begins to distort. Microphones with lots of headroom can be highly desirable, and often very expensive. However for most spoken word applications this headroom is not desirable beyond the on the bare minimum needed to make the audio sound natural. In order to reduce this dynamic range without losing desirable features of the microphone such as its frequency response and accurate voice reproduction we process the audio produced by the microphone through what is known as a compressor. The topic of compressors and audio dynamics in general is discussed more in our guide to audio dynamics and you should be aware that it is not necessary how to use a compressor in all speech applications. indeed in the world of TV where lavalier mics are more common for live applications it is very rare to use compressors at all. But if you are pre-recording speech for a show you should consider asking our audio resources team how they recommend processing your voice in order to get the nicest sounding output, which will likely involve the usage of compressors within your DAW.