What Is A Microphone Array & What Does It Do?
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When we think of microphones we usually imagine a concert, the recording of a record, or even that uncomfortable school event that haunts us until today, but what about the microphone array?
Something that often goes unnoticed by many is the importance of microphones in our lives.
Not only are they silent heroes, but they are incredibly important to virtually all entertainment today.
However, they are not only used to record Taylor Swift or the new Star Wars movie, because, within a certain organization, they can also serve many more complex things.
Table of Contents
What Is A Microphone Array And What Does It Do?
The subject of today’s article is the microphone array, an audio mechanism that organizes microphones in a certain way and so when connected to a computer allows for diverse results.
Before talking about microphone array, we’ll be talking about a little history of microphones, how they have evolved, some manufacturers, and more.
That’s not all as we’ll be looking at other associated things about microphones.
A Little Bit of History
Before touching on the background I would like to start with some history, I have always found it essential for learning.
I would like to begin by distinguishing three purposes that the microphone serves: the recording, transmission, and amplification of sound.
Some experts consider that sound amplification corresponds to our first experiences with the concept of “microphone”, although I differ a little and see that more as a megaphone.
In any case, since 600 B.C.
we have been amplifying our voice, using masks in fun ways so that the Greeks can do their shows better.
It may sound funny but when we first transmitted sound from one place to another it was around 1600 when someone thought of sticking a wire to two cups on their ends, like when we played in school.
Now when we refer to sound recording perhaps we should thank Alexander Graham Bell, when he included a device to capture and transmit audio in what would be the closest thing to the first telephone, all this around 1876.
Despite all these advances, a more stable and functional version would not be reached until the invention of the carbon microphone, thanks to Edison in 1886.
This type of microphone worked almost until 1970, which proves its success.
As you can guess (I hope), the microphone allowed the first radio broadcast in history, which was a performance at the famous Metropolitan Opera House, around 1910.
It was around 1963 that the company Electro-Voice created the “Shotgun microphone”, the first or one of the first unidirectional microphones, which allowed for much more precise sound.
By the way, Electro-Voice still exists and if you are wondering about the current models, we must thank (at least in their design) the Shure brothers and their models SM58 and SM57, whose solid constitution, audio quality, and reliability have made them practically the quintessential microphones.
The rest is, as I like to say, history.
For now, let’s continue with the story that brought us here, but if you are passionate about history and want to know more, I recommend the simple page that Encyclopedia has on this subject.
Microphones for Dummies
I think the easiest way to put it’s that these devices basically work as “translators”.
I don’t want to get scientific but the sound is actually something like waves.
The work of the microphones is to capture these sound waves and transform them into energy.
More specifically, electrical signals can later be amplified, retransmitted, or recorded.
As I hope you already know, these devices are used in many other devices, such as telephones (we already know, right?), and video game consoles.
About the Microphone Array
So what’s the microphone array?
To begin with, a simple way to see it’s that it’s a group of microphones (although there can be at least two), which work all at the same time or together, to capture sounds and draw conclusions or results from them.
These microphones must be of the same nature or type because a difference in audio quality will affect the expected results.
How does it work?
For an array to exist, there must be at least two microphones working and recording at the same time and connected to a computer that records both tracks in parallel.
Some very simple two-axis audio can be purchased at a fairly low price.
Once the array is working properly, you should have two different tracks that, if installed correctly, will allow you to separate the number of sounds by the same number of individual microphones.
I think it’s possible to say that there is no limit to how many microphones can be part of an Array.
Directionality is important here, as the array can be composed of unidirectional or omnidirectional microphones or a mixture of both.
The arrays improve the quality of the captured audio because they are arranged to focus on receiving radiation patterns from a desired direction and signal, thus “cleaning” the track of much of the interference and obtaining a higher quality “decanted” sound.
I hope that this was not complicated because now I would like to talk more about the uses, which as you will see are not as strange as you may have imagined.
Uses of a Microphone Array
What you use a microphone array for will depend on your intentions, because the microphone array has many uses, such as producing sound or detecting the audio source.
The most common way to use them is by putting two microphones to work together on opposite sides.
This generates the possibility of capturing audio and creating a more enveloping sound.
The military, for example, uses complex microphone mechanisms to detect the origin of audio and detect the enemy.
This is achieved by establishing a delay in the sound reception of some of the microphones that are part of the system, something that can be very precise.
Even if you haven’t heard of them before, it’s safe to say that they are relatively popular devices as they offer to produce a dynamic sound without the complexity of having a whole team of workers or several messy microphones.
It Can Be Used for Different Tones
A super important aspect of the arrays is that the microphones can be configured to listen to only one type of tone or a particular frequency.
For example, this is especially important for orchestras.
It’s not the same type of sound that an organ or keyboard produces as it’s different from the sound produced by a guitar or any wind instrument.
It’s Used to Separate Sounds
For the creation of the famous stereo sound, whether for video games, music, or other media, it’s common to use a “dummy head”, with a microphone in each ear, which will simulate human hearing.
This is very important, so the next time you enjoy the new Jurassic Park you might want to thank a “mannequin head”.
This is known as binaural sound, whose examples can be found on Youtube in the form of relaxation and concentration tracks.
As you can see, these microphones that must work at the same time can be arranged in various ways, either in all directions, along a surface, or around something.
Something that the microphone array allows and is very important especially in entertainment production is that you can separate different “parts” of the audio because you can separate the noise from the environment from the voices or music.
This is something very important in show business.
What do Normal Microphones Do?
It should be noted that ordinary microphones pick up the sounds of their environment in a “disorderly” way; in the sense that they do not distinguish any of the tracks or (for the most part) do not offer the distinction of what you want to hear from the background noise beyond the volume.
For this reason, arrays are especially important or useful in noisy places because without the need for complex software, it allows you to isolate what you really want to hear.
Also, take into account that the quality (and price) of the product matters, because the more specific a piece of equipment is, the greater the sensitivity and quality it has.
Besides, specialized commercial equipment (as mentioned above) can take away your need to use computers for large calculations or complex software.
Another difference is that arrays are not only set up to capture particular patterns but also based on the very position of the equipment.
As a curious fact, one of the most important microphone arrays in the world was built in 2014 by MIT, and it can work as a compass.
However, the one that currently maintains the golden clasp is the one built in Holland and consists of 4096 individual microphones, being its creator the Dutch acoustic engineering company Sorama.
According to Guinness World Records, and as you may have an idea, this marvelous device can take a 3D “photograph” of the sounds around it.
Not only that, but it’s also capable of recording over 4000 different sounds in one second.
Homemade Microphone Array
If your thing is to create your own things, there is also good news for you.
You can assemble an array, you just need to buy more than one microphone of the same type and arrange them in the right way, obviously, connected to a PC.
I also want to make it clear that a microphone array is not the same as filling your parents’ basement with microphones.
On the contrary, a well-assembled array eliminates the need for messy microphones all over the place, as these devices are based on three factors.
Checklist for an Array
A microphone placed in one direction will pick up all sound coming from that place (it’s unidirectional, duh), while some pickup sound from all sides (yes, omnidirectional, genius).
In an array all must have the same directionality, otherwise, the result will be a sound disaster that will not serve you to participate in the local music fair.
Your microphones must have a sensitivity at least close, otherwise, you will have a track with unbalanced sound.
This depends more on what you need, but in general, you don’t want there to be too much difference between the time it takes for one microphone to pick up sound from another.
Wireless Microphone Arrays
The arrays can also have wireless microphones as part of the system, although usually there are several of these condensed and installed in mounts.
The famous wireless acoustic sensor networks (WASNs) allow the design of specialized arrays, which can be even more precise and capable of higher quality than common instruments, although this is a little more advanced.
These audio systems have been around for some time, but it has been the rapid advance of technology that has allowed, that it’s a more present object.
Today they can be seen in offices and other workplaces, being quite common especially when producing content.
Just imagine the closeness you can have with your beloved math teacher with a proper array coupling next to a webcam.
I would also like to point out that they can greatly improve virtual meetings by allowing a group of people to be in a room with an array that allows them to have participants online.
In the case of meetings or conference rooms, circular microphone array systems or circuits can be installed.
We can also see it with an auditorium with a speaker, something like a new century Ted Talk or an opera recital for a digital audience.
Of course, this not only increases the quality of the audio but also prevents interference with the audio.
It also ensures that each speaker is heard as well as possible without any errors in the sound.
(Remember how annoying the high-pitched noise of two separate microphones can be when they get very close to each other or when they get close to the speakers).
Arrays are used daily, but they are an invaluable aid undervalued by most people.
It’s not usually explained that arrays exist as a “different” device from conventional microphones, which surely impacts how people perceive them.
I have worked closely with arrays relatively recently and because I am writing this article I have discovered much more about them.
Now, to you, an aspiring musician, I’d recommend not only read about the arrays but also, understanding and looking for how technology makes your work easier in an extraordinary way.
It’s without a doubt one of my passions to learn new things and expose them, hopefully, this has awakened a lot of interest and new ideas in you.