Why Microphones are so Confusing.

Because no one mic can do everything, each mic has it's own niche. Microphones come in two basic types - those which need power and those which don't. But within each type, there are dozens of configurations and sizes. Size and configuration is determined by 1. Where the microphone is to be used. 2. What the sound source is, and 3. What it will be plugged into.

As you can imagine, that's a lot of variables. And so choosing a mic depends very much on what you're going to use it for and where.

Manufactures would recommend you get one mic for each set of circumstances because you're unlikely to find one which does everything perfectly, at least not without it falling apart or being too big. And that is why there are so many to choose from and why it's confusing.

1. How to Choose a Microphone Based on Where it will be Used.

This is usually the main determining factor of choice. Inside, in a studio, or a stable environment such as classical music concert, then a condenser mic or a ribbon mic will be the go to choice.

This is because they are sensitive and offer great detail and have certain flexibilities in how they're used and positioned.

The trouble is that they are complex, usually big, easily damaged and expensive. They're also susceptible to changes in temperature and humidity.

So outside, and especially for a loud stage environment - a dynamic mic will usually be good enough. They are usually lighter, tougher and less sensitive to unwanted noise from other musicians.

What is a Condenser Mic ?

A condenser has two metal plates, one of which moves as the sound waves push it. The distance between the plates changes and produces a small electric charge. This is then processed as the sound source.

Condenser mics need a small electrical charge to operate called, 'Phantom Power.'

Condenser mics can be really big or tiny.

What's the Difference Between a Small Condenser and a Large Condenser ?

Well that is fairly obvious in the name and refers to the size of the metal plates. Large being 3/4 to one inch and small being less than that.

Some small condensers are tiny, 5mm or less.

Small condensers are great for lapel or wireless applications, but have limited bass response.

Small condensers around 1/2 inch are often used for string instruments and cymbals or anything which has a lot of high pitched detail. Because the smaller plate reacts quicker to high pitches.

What is a Ribbon Mic ?

Ribbons were the first mics to be invented and used commercially. They use a ribbon of aluminium suspended between two magnets to generate the signal.

They are very sensitive, very easily damaged and difficult to use. Ribbons need to be matched with a good quality mic pre-amp. ( See below. )

They're used mostly for vocals because they do offer a distinctive sound but in recent years, are being used in increasing numbers for other applications.

Ribbons do NOT need phantom power.

What is a Dynamic Mic ?

A dynamic mic works in the exact opposite way to an audio speaker.

A magnet sits inside a coil and when sound waves hit the diaphragm attached to the coil it creates and electric signal which is then processed.

Dynamic mics are rugged, reliable and less prone to environmental issues. They are the least sensitive of all the microphone types which makes them especially suited to busy stages where there are many sound sources.

It is jokingly said 'you can just plug a dynamic mic into a wall and it'll work.' Well you can't. But they don't need power and they do work even when you don't think they will, and often sound good when you don't think they will.

Dynamic mics are mostly designed for live stage so that they fit in the hand or a standard mic clip.

They are generally less sensitive and the lack of detail is usually noticeable in the 't's and 's's of speech - in that they become 'splashy' and less distinct. However, a high quality dynamic mic is often plenty good enough and sometimes as good as other types, even in the land of the 'splashy' detail.

Some dynamic mics like the Shure sm7b are bigger and made for studio use.

What is a mic pre-amp ?

A microphone pre-amp amplifies the signal to 'line level,' so that it can be recorded or passed to a power amplifier which can turn it into something we can hear.

A microphone turns sound waves into an electrical signal, but that signal is very weak and prone to interference and noise.

Most other types of amplifier are only sensitive to, and capable of amplifying 'line level' signals. They can't even hear the signal generated by the mic let alone do anything with it.

That means, if you have a microphone, you definitely need a microphone pre-amp.

Most audio mixers have built in pre-amps. You can also buy them separately.

As with microphones, there is a lot of hype and glamourfuss attached to pre-amps. Unless you're using a ribbon mic, the pre-amps in a mixer are nearly always good enough.

What is a microphone pattern ?

All microphones of all types have a 'Polar Pattern.'

This is the amount of sensitivity a mic has around it's axis. There are basically 3 patterns. Cardioid, Omnidirectional and Figure 8.

Cardioid

More sensitive directly in front and least sensitive behind. Usually found on dynamic stage mics and most condensers. The advantage being, stage noise and other sound sources are less noticeable. The disadvantage being a jump in bass frequency response as you get closer to the mic.

Supercardioid, hypercardioid, shotgun, are all variations of cardioid with an increasingly forward focused sensitivity.

Omnidirectional

Sensitive through 360 degrees. The advantage being it has the most natural sound of any polar pattern. Most useful in a good room or studio where you can control other noises.

The disadvantage is that it will hear all sounds in close proximity, even those you don't want.

Figure 8

Sensitive both front and rear but not at the sides. Creates a unique sound and is extremely useful for studios. Especially making stereo recordings or recording two singers for example.

All Ribbon mics are Figure 8.

2. Choosing a Mic Based on What The Sound Source is ?

Any mic will record any sound source. And although I've suggested you may need a couple of mics for different environments, you don't need a special mic for this drum and a special mic for that drum.

That being said, no one mic can do everything perfectly - they just aren't as tolerant and adaptable as human ears. And you don't want to wreck your expensive condenser mic by sticking it next to a trombone either.

Remember, drums and brass and some singers, are incredibly loud. Acoustic guitars are really quiet. Loud sources will damage sensitive microphones and quiet sources won't make good clean electrical signals.

The only sure way is to read the instructions and sales literature. All mics are designed for a specific purpose. If your budget means you have to choose a 'good all rounder' - it's all right. Use your own ears and don't get all up tight about the right mic.

The only time this becomes a real headache is with vocalists. Sometimes, singers just sound bad with one particular mic. Sometimes they don't like how they sound. Again, try different stuff and trust your ears, and maybe your gut too.

3. Choosing a Mic Based on What it Plugs into ?

Most modern microphones use a standard 3 pin connection called 'xlr'. Most of the time you won't have a problem. But there are always situations when what you can't plug in for some reason. There are dozens of adapters available which will usually work with a dynamic mic - with condensers though - it can get tricky. Especially with lapel and wireless mics.

In fact the smaller your mic, the more specialised and expensive the connections are likely to be. All the manufacturers have huge appetites for creating their own specialised connections for small form mics, it's a real headache and hideously expensive.

Standard mics have standard 'xlr' connections - but that doesn't mean connecting em is a breeze.

For example. If you have no phantom power available and your condenser mic does not have it's own battery, then you will be forced to use a dynamic mic. A ribbon is also out because if you have no phantom power, it's very unlikely the pre-amp you're using is going to be good enough to drive a weak ribbon signal.

I've been in several situations when nothing works and suddenly an overlooked dynamic mic does, even when it shouldn't.

For example, some budget mixer manufacturers aren't truthful and transparent about which inputs have what features - even in technical manuals.

Never under estimate a dynamic mic - they can often save the day.

How to Tell if a Microphone Needs Phantom Power.

You can't - the only sure way is to read the instructions.

Once you become familiar with what a condenser or dynamic mic looks like, you could guess and you might be right. But you could accidentally apply power to a very expensive 'Ribbon' mic and cause permanent damage. So if you're not 100% positive, read the instructions.

Which Microphones Types Need Power ?

Condenser, Hydrophone, Electret Condenser, USB ( usually gets it from USB connection )

Which Microphones Types Don't Need Power ?

Dynamic, Ribbon,

What is Phantom Power for Microphones ?

WARNING : Microphones which need power DON'T connect directly into a mains voltage supply. That is extremely dangerous and you should never attempt to do it.

Condenser and Hydrophone microphones need 'phantom power' which can be supplied by a small battery, a special adapter, an audio mixing desk, or an audio interface. USB microphones get their power from the USB connection.

A mic which needs power is usually far more sensitive than one which doesn't. It creates a bigger signal so it is louder. It has less self noise, has more accurate reproduction and more options in terms of the quality of sound.

Why are There so Many Different Types of Microphone ?

Two reasons. Because there is a lot money to be made by selling microphones. And no one microphone can do everything perfectly. That's why there are so many and why it's confusing.

People get obsessed with microphones and believe getting the exact right one will make them sound better. And that may be true, sometimes. After all, you usually get what pay for, especially with microphones.

But there are genuine practical limitations which determine what mic you should choose for a given situation. We all want the 'best sound' but taking an expensive condenser mic to live gig in a noisy environment can be foolhardy and pointless. Especially if it gets damaged or stolen. And if you're on the move, you can't be stuck with heavy mic in a fixed position, you need one that clips onto your clothing or the side of your head, and it may need to be wireless.

How to Choose a Microphone Without Getting Confused.

If you can afford it. Choose a Large Condenser mic because they are nearly always more useful and more faithful in reproducing sound. But consider where you'll use it....

Condenser mics are very sensitive and easily damaged. So if you are a bit clumsy, it would be better to go for a dynamic mic which will stand a few knocks. And don't forget you'll need phantom power for a condenser, you can't just plug it in and expect it to work.

Also, if you're blowing a trumpet into it or hitting a drum, you'll need a mic designed especially for loud sound sources. Those tend be dynamic, but not always.

For speech only applications like podcasts and vlogging etc, there are some specialised dynamic mics for inside studio use which are exceptionally good value. The Shure sm7b for example.

For wildlife and outdoor recordings, you'll need a shotgun mic which are designed for the job.

The big known brands are usually best, but not always. The Shure SM58 is the best selling mic in the world, but there are several tougher and better sounding mics in that class for the same price.

Cheap microphones tend to be very unforgiving. Buy the best you can afford. Then you can stop fretting over it and wasting money on stuff which is harsh, prone to feedback and breaks after 12 months.

Are Microphones Analogue or Digital ?

All microphones are analogue, they turn sound waves into an electrical signal. There are no ones and zeros.

Summary

It is incredibly easy to get wrapped up in the wizardry and hocus pocus which surrounds the craft of microphones and their use.

You can also spend thousands of dollars on imaginary perfection only to discover that your recording environment is a hopelessly unsuitable. It's often miles cheaper and more effective to place the mic closer to the sound source - and that means a buying a mic designed to do that.

Look at what others are using in the same environment, choose a known brand - but most of all, trust your own ears.