Do All Condenser Mics Need Phantom Power? – nt1a, AT2020


  

  

 This is a question I get asked a lot, people will often email me asking if a specific model of condenser microphone, for example the Rode nt1a, the Rode nt1 or the Audio Technica AT2020 need phantom power to work. Well I thought I would do one article which answers this question for every single condenser microphone out there because the answer is always the same:

Yes, for ANY condenser microphone including the Rode nt1a, Rode nt1 and Audio Technica AT2020 you will need phantom power in order to get them to work. This is because of the way condenser microphones function. A small amount of electrical charge (phantom power) is applied to a thin metal diaphragm and backplate and when a soundwave hits the diaphragm it produces a small electrical current which is boosted and sent back along the audio cable to the interface, mixer or amplifier.

That summary is very brief and if you want a more detailed explanation of exactly how condenser microphones work, why phantom power is needed and finally how you get phantom power then please read on.

  

How Do Condenser Microphones Work?

  

So the best way to understand why phantom power is required in all condenser microphones such as the Rode nt1a is to understand how they function.

All microphones, regardless of type are what are known as ‘transducers’. This sounds really technical, but really all that means is they convert one form of energy (mechanical) into another form of energy (electrical). Which allows physical sound waves to be translated into audio signals for you to hear through speakers or an amp for example.

The way different types of microphones perform this task though varies depending on the microphone design.

There are two main types of microphone you are likely to come across in your musical journey (there are of course other types but they are less common). These are dynamic microphones and condenser microphones. If you would like a detailed description of the difference between these two types of microphone, check out this detailed article I wrote.

A dynamic microphone, you may associate most with the type of microphone singers use in a live setting. They are an older, simpler design which contains a thin piece of material known as a ‘diaphragm’ which is attached to a metal coil suspended between two magnets that moves when a sound wave hits it. This creates a small AC current and that passes down a cable and into an amp where is converted back into an audio signal for you to hear. As simple as that.

A condenser microphone such as the Rode nt1a, nt1 or Audio Technica AT2020 is a more intricate piece of kit, and that is usually reflected in a higher average price.

In a condenser mic the diaphragm is usually a very thin piece of conductive metal (this is often a very long lasting corrosion resistant metal such as gold. Then there is a second thin piece of metal known as the ‘backplate’. A small amount of power is applied to these pieces of metal causing a static charge between them. This means when a soundwave hits the diaphragm it begins to move ever so slightly, when that happens the ‘capacitance’ of the circuit changes ever so slightly and it creates a tiny electrical output.

1) Sound Waves 2) Diaphragm 3) Back Plate 4) Battery 5) Resistor 6) Audio Signal (Image: Wikicommons 3.0)

As I say, that electrical output caused by these minute changes in capacitance is very small indeed and therefore condenser microphones also contain a small amplifier, known as an FET amplifier. This boosts the signal and means you will have an audible signal with enough juice to travel down whatever cables you are using to your audio interface, mixer or amplifier.

  

What is Phantom Power?

  

Phantom power is the source of that small electrical charge required to make your condenser microphone work.

It is a D/C (direct current) voltage that is transmitted over an audio cable.

The reason for the spooky name is because the power is transmitted down the same cable audio cable that you will be using to end audio signals down from the microphone. So there is no need for a separate plug or cable to provide power to the microphone. It is effectively invisible, ‘piggybacking’ on the A/C current and so hence the name ‘phantom power’.

Most of the time for microphones you will be using an XLR cable. The 48v D/C current is supplied through pins number 2 and 3 of the 3 pins, whilst pin number 1 is the ground.

  

Where Can I Get Phantom Power From?

  

So now you know that you need to get phantom power to your condenser microphone for it to work, how do you do this? What equipment is needed?

In the home studio, the most common source of phantom power will be an audio interface. This is a small, but essential, piece of kit that is essentially an external soundcard and translates the audio signal from the microphone into a digital signal your computer can understand.

On virtually all audio interfaces you will see a button either marked “phantom power” or more commonly ‘+48v’ such as on my Focusrite interface shown below.  The 48v is the industry standard amount of phantom power that is supplied by an audio interface to your microphone.

  

  

You will also find phantom power on most modern mixers. So if you are looking to use your condenser microphone in more of a live setting and want to connect it to a PA system or amp, it will need to go through a mixer which has phantom power abilities. Once again have a look for a button or switch marked ‘+48v’ or something similar. If you are unsure the manual should tell you whether or not it has it.

In reality though, you are much better using a dynamic microphone when not in the studio. Dynamic microphones do not require phantom power, but also have a more robust, rugged design, better suited for louder sounds and being knocked about. Because of their intricate designs, condenser microphones are much more delicate and prone to damage.

  

Do USB Condenser Microphones Need Phantom Power

  

USB condenser microphones have become very common in recent years. In fact, many of the models mentioned here such as the Audio Technica AT2020 have a USB version of the same mic.

Well yes, these microphones do still require phantom power. As I already mentioned this is due to how the mechanism functions. However, you do not need to worry about having a special interface or mixer for this, the phantom power is supplied to the microphone through the USB connection.

This is what makes them a very popular choice for many as they can just be plugged in an used, making them super portable and easy to use.

  

Can Phantom Power Damage My Microphone?

  

This is a common question. The idea of applying an electrical current to your brand new piece of equipment can seem a bit daunting but trust me in most case it should be ok.

Even if your microphone does not require phantom power, if you try to use it the current will simply travel to the ground pin on the XLR connection and will bypass the microphone. For more detail on why dynamic mics don’t need phantom power check out this article.

The only time you need to be careful is if you have a ribbon microphone. These special microphones have a very thin ‘ribbon’ element which can be damaged by phantom power. But let’s be honest the chances of you accidentally having a ribbon microphone without realising it are slim to non.

  

Conclusion

  

Yes phantom power is required for any condenser microphone, including the Rode nt1a, the Rode nt1 and the Audio Technica AT2020, in order for them to function correctly.

But this isn’t something you need to worry about. When buying any XLR microphone you will need to buy and audio interface or mixer to connect it to you laptop or computer to record and with virtually all modern interfaces, even cheap ones, phantom power comes as standard.

If you are undecided which microphone to buy still, check out this review of the nt1a I did and hopefully that will help you decide.   

Rob Wreglesworth

Rob has come to terms with the fact he will probably never be a famous rock star....but that hasn't stopped him from writing and recording music in his home studio. Rob has over 15 years experience of recording music at home.

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