The Basics of Microphones

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Written By Tanya

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Let me tell you what the bottom line is. There is a lot of information on the internet about microphones that is not factual. To be able drive a car, you don’t have to understand every part of the engine.

Even experienced recording studio engineers can’t remember all the microphone types because they don’t all use them in their day-to-day jobs.

It’s true that you don’t need much knowledge to use a microphone. Most of it can be’set and forget’.

We’ll cover the basics so you can communicate with professionals without getting lost in their ramblings.

This is your chance to go on a journey with no explanations, so you can use any microphone you find in real life. You will also understand why you need to do the things you have to to achieve the best recordings and performances.

It is not difficult and anyone who makes it seem hard is lying. Let’s get the party started.

It boils down to knowing that there are many types of microphones, but you will mainly only need two. Each mic may have different ways of changing the direction of the sound they record, beyond pointing it at an instrument.

It is important to be able to adjust the volume, use the switches, and connect your gear to it. There are a few other concepts that you need to know, but not necessarily have to memorize. It’s easy! Let’s do it in the same order.

Note: While we keep this simple, if you find a topic that interests you and you’d like to read more about it, click the link to one of our longer articles. You don’t have to leave us hanging. However, you can forgo those links and return at any time. For now, just take in the basics.

These are the Two Major Types of Microphones

You can search for all microphone types and you will find both long and short lists, as well as many that differ from each other. There are many types of microphones: shotgun mics; boundary mics; ribbon mics. However, most hobbyists and recording engineers only use the two below types.

DYNAMIC MICS

The dynamic mics you will see most often on stage are those that have the sound directed down the front of it. They can handle louder sounds because they are less sensitive to volume and damage.

The diaphragm vibrates when sound pressures are applied to it. In dynamic mics, it moves a magnet through the magnetic field of a wire coil. This allows electricity to flow. This system is known as a Transducer. It works in a different way in a condenser microphone, which is what makes them unique.

CONDENSER MICS

These mics are what you will find in recording studios. These mics are aimed directly at the sound source.

They can sense subtle changes in volume and are sensitive to small changes. This is why they are preferred in studios where the acoustic environment has been tightly controlled.

However, you could damage the tube or larger diaphragm if you record too loudly or drop it. The transducer allows the diaphragm vibrate closer to a charged metal plate. This is why condenser microphones require Phantom power or another power source such as a battery, or its own power supply. The red arrows indicates the direction of sound delivery

You will find all of the above mentioned information again in the following paragraphs.

Patterns for Microphone Pickup

Many mics are very simple to use. It’s as simple as pointing it at the sound that you want to broadcast or record. Many also have ways to alter the sound it picks up, without having to change their direction. These settings are called pickup pattern.

These pickup patterns are often referred to by the terms polar patterns, directionality, polarity and polarity. All of them mean the same thing. Most mics don’t allow you to change the pickup pattern.

This pattern is the most popular because it captures a large field in front of microphone and blocks out noise from behind.

Imagine a singer on stage. The crowd singing and cheering behind the mic is not what you want coming back through the speakers.

Only the singer’s voice should be captured from in front. The majority of other pickup patterns are variations on the cardioid, but there are still useful ones you will rarely use.

These patterns are available in three basic styles:

  • Unidirectional
  • Bidirectional
  • Omnidirectional

These indicate that the mic can record sounds in only one direction (front), or two (front & back), but not all 360 degrees. The cardioid pattern is unidirectional and will be used most often. This is how it looks: The extremely common cardioid pickup pattern

Although it picks up most sound from the front, it will still pick up some sound from the sides at a lower volume. These patterns are sensitive to sound, as shown in the image. The darker black lines that extend outwards in the circle correspond to higher volumes (measured by decibels).

Instrumentalists and vocalists with experience can use this sensitivity. Singers will move closer to the microphone when they are louder, in order for them to better control their volume. Studio engineers have another advantage: they can use sensitivity to their advantage. We’ll discuss it next.

The proximity effect

Close miking is the best technique to set up a microphone on stage or in the studio. This means that the microphone should be placed within 12 inches of the sound source.

This allows you to increase the volume of the recording you are making, and decreases other noises such as the whirring of computers or other instruments.

You would think everything was fine. All you have to do is place the microphone right next to a singer and you are done. There is a strange effect when you close the gap between the microphone and the sound source.

You’ll notice a difference in bass volume when you reduce the distance to 12 inches or less. This is the proximity effects. The colored globes represent the increasing bass sensitivity of the proximity effect

You don’t have to be concerned about this yet, but it is something you need to know. This is how radio DJs achieve a smooth, deep voice. Some microphones exhibit a stronger proximity effect than others. This effect can be seen differently in different pickup patterns. If you are going to use cardioid, stick to it.

This is a problem that you only see in dynamic mics. Because condensers can’t be too close to the sound source, they are too sensitive. While close miking is possible with condensers, it can cause damage if you use too much SPL (Sound Pressure Levels).

Get Staging Levels For Mics

This is the most important aspect of any discussion about microphones. Pay attention! Recording the signal from a microphone has an extremely low electrical ampltude. This is also known as volume.

Every day, a newbie attempts to record a microphone and wonders why it is so quiet. Microphones spit out a mic-level signal. It is much quieter than an instrument level or line-level signal.

Preamplifiers are required to boost mic-level signals. You can’t increase the volume without increasing the noise. Preamps increase the signal without increasing the noise, and they are the only way you can get high-quality recordings.

The preamplifier is actually more important than the mic for quality recordings. The preamplifier adjusts the volume by sending the signal to it and then setting the gain knob. For the moment, gain can be thought of a volume knob.

Continue reading: What is a preamplifier? Why do we need them?

Let me take away your worries. You’re fine if you want to learn before buying any equipment to begin recording. Most people are familiar with what a recording interface does and is not. These interfaces come with preamps, so you don’t need to purchase additional gear.

We were discussing how to adjust the volume of your mic via the gain knob. But that raises the question: what volume should you aim for? This is a big topic that we cannot cover in detail, so I will try to condense it.

You will be monitoring the levels of your recordings in Pro Tools, Logic Pro or FL Studio when you record. Your volume should not exceed 0 dB. It should average around -18dB on the computer.

To understand why, please read the link below. This is essential if you want your audio quality to be the best.

You don’t need to go any further. It doesn’t matter if you do not have to now, but it is worth bookmarking the article. This is why amateurs make terrible recordings.

The Microphone Basics

Although microphones produce an electrical signal by moving their diaphragms they are not all capable of doing this without their own power source.

Because of the way dynamic mics are built, they don’t require an external power source. However, condensers do. When the diaphragm is subject to sound pressure, you must charge the plate towards which it moves.

Condenser microphones may require a battery. High-end models will have their own power supply. Most rely on the preamp for this power, in the form Phantom power.

The short version (see What’s Phantom Power?) is that the preamp will send +48 volts to the XLR cable, which feeds the mic. This is all you need to know. It’s easy to find out if your condenser requires it by looking at the documentation. You don’t need the power brick or battery on your condenser.

Most people are curious about whether you will damage your mics by turning on the Phantom power to mics that do not require it. No. It is a very small amount of voltage.

It won’t do any harm. To be safe, make sure to turn off the Phantom power before you plug in the mic cable or unplug it.

Microphone Frequency Response

You can’t do much about the frequency response of a microphone other than to read the charts provided by manufacturers or engineers who measured the mics again. Until you mix with an equalizer, it is impossible to change the frequency response (except for the two methods listed below, which are sometimes provided with switches on the mic).

When you look at frequency response charts, what you really do is determine the mic’s flavor. Some mics are transparent and produce a neutral sound, while others emit a color that alters the sound in some way. There are two types of ‘colored microphones’: dark and bright. The Rode NT2 response, showing bright coloration. The dashed blue line shows the bass roll off.

This is all about the frequency response. It is how the high frequencies respond to a boost, and whether the low frequencies do the same. The decision will depend on the instruments you plan to use and whether your voice is deep or high.

Some people perform better with different sounds sources. Studios keep a variety of mics in their locker so that they can choose the best mic for the singer or instrument.

A bright or neutral mic is a better option if you have a limited budget. It will sound great on all sources. The rest will be done in the mixing stage.

High Pass Filter and Bass Roll Off

There are two ways to alter the frequency response of the mic while recording. These switches are not available on all mics, but they are common in those with two or three.

A few will include a pickup pattern switch, while others will have a pad to lower the output amplitude by 10 dB. This is useful in cases where you are recording very loud sources or with high volumes.

You can find the main switch I am going to talk about in any of these four ways. All of them indicate the same function. They can be high pass filter, low-cut filter, bass rolloff, or an image of a straight line that represents the bass region of the frequency range.

All of these reduce the volume of bass that is made into the output signal. However, the lower the bass frequencies are, the slower it will do this.

This rolloff may occur at 1 dB less, for example, from 100 Hz to 200. At 60 Hz, you might be at 3dB. The volume will drop by 5 decibels at 40 Hz. At 20 Hz or below, you might see up to 10dB of dampening.

This is done to block out ambient noises like the rumbles that travel through the floor, up your mic stand, and the low hum of an air conditioner outside. These areas are not conducive to the sound of most instruments or vocalists, so you can benefit from turning on the switch.

You can always do this roll off during mixing, if you don’t want to commit upfront. Even if you use the switch, I believe that your mixing engineer will roll off that area regardless. You have the option to use the switch or not if you are recording a cello, bass guitar, etc.

The Main Types Of Microphone Cables

This is a short and simple explanation. Two main types of cables will come out of traditional microphones. These cables are either an XLR (or TS), cable. You will see many podcasters and streamers purchasing USB microphones that utilize USB cables these days, but I don’t recommend them personally.

You can be certain that the entire mic will suffer from poor quality if you try to fit the converters and preamp into the mic. This is especially true when you consider the cost of these USB mics. We all know what a USB cable looks like, so let’s take a look at the two other options.

XLR cables are usually balanced and carry mic-level signals. They also don’t accumulate any electrical noise over long distances. You can find out more about this by clicking the link above.

Mics with TS cables can sometimes be seen. These cables are often unbalanced and generate noise. They cannot carry mono signals, and they are often used for instruments. The balanced, stereo-capable version of the TS cables is the TRS cable.

Although the story behind the XLR cable’s name is lengthy, it simply stands for X_series connector with a Locking Tab and Rubber ring. TS stands for Tip-Sleeve and TRS stands to Tip-Ring-Sleeve. This is how you visually distinguish the two.

Studio quality microphones almost always use XLR cables, but you will see plenty of TRS and TS cables along with your other gear.

Microphone Basics: Plosives & Sibilance

This section is about recording vocals. However, you need to be familiar with the sibiliance words and plosive.

Pops are the “explosive sounds” made by singers when they create syllables that begin with a P or a B. To create these syllables, we need to blow air fast so that our sensitive microphones can pick them up. These are three ways to approach them. I recommend at least two of these methods each time.

  • To allow air to flow by the diaphragm, turn the mic slightly off the axis.
  • A pop filter intercepts some of the air and forces vocalists to maintain a certain distance.
  • To catch any air bursts that are headed towards the microphone, use a windscreen.

These two are usually sufficient. However, if you’re not confident, you can use all three. You won’t have to compromise your sound quality if you buy a quality pop filter or windscreen from a reputable studio gear company.

Sibilance is the distinctive piercing sound that many singers make when they form syllables starting with an S or T. This gap can be between your roof, your tongue and your back teeth. It can also contain a very hidden, high-pitched burst. It’s not something we notice in our daily lives, but our sensitive microphones can pick it up.

This can be dealt with by using a deesser. It means what it sounds like. It eliminates the S sound. A de-esser is essentially a compressor that has an equalizer side-chained.

This allows you to tell the compressor that it will reduce the volume at the frequency at which the sibilance is occurring, but not affect the other frequencies.

How to Buy a Mic

When you begin searching for your first microphone, it is easy to get overwhelmed. To narrow down the choices, you will need to set some parameters.

It is important to decide what your main purpose for using your microphone. Are you using it to record guitar and vocals? Are you looking to record a guitar amplifier? Perhaps you are interested in recording piano.

Do you need one that does it all? These questions will help you narrow down your choice of color and frequency response.

These lists can be found online. I recommend going bright or neutral for any instrument other than a bass or a vocalist. Darken those.

The same questions can help you decide if the microphone’s pickup pattern should be changed. Unless you intend to use two mics, you will need a microphone that is more capable of recording the piano.

You might also want to record vocal duets, but only one microphone is available. In this case, you may consider mics that can perform the Figure of Eight pickup pattern.

The last thing you need to decide is whether you want either a condenser or dynamic mic. It is often based on two factors. The first is the environment in which you will use it. You’ll need a dynamic if you take it on stage.

A condenser is the best choice for studios, unless you have to isolate the sound source from the rest of the room. A dynamic microphone is a good choice in such cases.

Your budget will be the last determining variable. You’ll likely be searching for a condenser microphone if you fall into the “neutral” or “bright” category.

This article has great recommendations for all budgets. Although we don’t include dark condensers in this article, they are definitely there.

We have the right article for you, regardless of your color preference. We’re sharing our top picks in every budget.

After narrowing down your search and clicking on one of the links above, you will find our recommendations as well as links to our mixing and recording tips for each case.

How to Use a Mic

Let me clarify some things for you. You can’t buy a microphone and just start recording. This is something that most people know. To address this problem, USB microphones were introduced to the market. There is a lot of recording equipment that beginners will need in order to produce music and record vocals. This is just one piece of the puzzle.

They are the key to success because you won’t be able to achieve the same quality as a fully-equipped setup. Although there is definitely a barrier to entry, it’s much easier than most people believe.

You will need a microphone stand and a windscreen and pop filter. If the mic you select doesn’t include one, an XLR cable may be necessary. What about those items that aren’t obvious?

These are not the technical details I will be discussing, but it is important to know that the mic must send its signal to a preamp which then passes it on to digital-to-analog converters. The signal is then sent to your computer via a Thunderbolt, Firewire or USB cable. This is the most common method for most people. Focusrite Saffire Pro 40 – My own current audio interface

Now, don’t get upset. These items don’t have to be purchased separately. However, you may eventually want to if you get serious about recording. There’s an audio interface which has everything you need in one box.

You will only need to plug your mic in and adjust the preamp gain. The rest will be done for you like magic. You will need to know how to get it to record once you reach that point. I’ve got you covered.

To reduce the complexity of microphone basics, you only need a mic, an interface for audio, and a computer. Everything else can be considered cheap accessories.

These are the basics of a microphone…

This is the most complete, concise and comprehensive guide you will find to microphones. It doesn’t attempt to impress with long words. Recording with a microphone doesn’t need to be difficult.

You’ll be all set once you have connected everything and set up your DAW software to record. You can set it and forget it for most of the time. It’s impossible to function without one, so make sure you check out our list of best DAW and get one.

It is important to get the technical details out of the way in order to focus on the artistic aspects of your operation. Thank you for reading my brief lesson on microphone basics.

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