- Find out the practical uses for a shotgun mic
- Learn when a boom mic would be used
- Understand shotgun mic polar patterns
- Also, check out our separate guide to the best shotgun mics.
Choosing the right microphone for a given situation can be tricky (although we’d always go by the rule of ‘there is no wrong choice’ if you’re experimenting!).
If you’re looking into purchasing a mic for video production, studio recording, or even live streaming then you’re likely going to see condenser or dynamic microphones mentioned.
However, you might want to consider a shotgun microphone if you’re looking to capture speech.
Why a shotgun mic? Well, they tend to have extremely accurate sound quality due to their hyper-cardioid polar pattern, meaning they will reject a lot of ambient background noise or unwanted off-axis sounds.
When would a shotgun mic be used?
Shotgun mics are often used when recording voice, whether that be in films and TV or live-streaming.
As we’ve mentioned their polar pattern allows a crisp and clean recording whilst rejecting a lot of unwanted background noise that you would often pick up with other omnidirectional mics.
Think of a busy city scene in a movie, it would be almost impossible to find a location that wouldn’t have some background noise, but a shotgun mic would allow the sound engineer to capture as clean a take as possible by isolating actors in the scene.
You might be wondering why background noise is an issue, after all, if a movie scene is filmed in a city then the viewer will naturally expect to hear the sound of city noises. The main reason is control during post-production.
When it comes to editing a voice you want the voice to be as isolated as possible so that when you begin to use EQ and compression, you aren’t boosting or enhancing other sounds other than the actor’s voice.
For this reason, foley artists and sound designers will add in extra sounds after the scene is recorded (such as ambient noise, traffic sounds, footsteps, doors opening, anything you see on screen!).
Are shotgun mics used in recording studios?
Technically they could be, but normally you’ll find a good selection of dynamic and condenser mics in a studio set up with omnidirectional and cardioid configurations.
The reason is the recording environment.
In the case of a studio, the engineer will likely want to pick up some of the acoustic qualities of the live room, particularly if they are recording drum overheads.
Therefore a shotgun mic would actually work against the engineer as it would mainly pick up the sound of the cymbals and much less of the room characteristics.
Typical condenser microphones are great for studio purposes but they will pick up a lot of extra noise that will really hinder things when it comes to dialogue recording on location.
In the same way that a shotgun mic is used commonly in outdoor settings due to their tight polar patterns, a condenser is used indoors for the opposite reason of wanting to pick up additional ambient sounds.
What is the difference between a boom microphone and a shotgun microphone?
You might be thinking there is a physical difference between shotgun microphones and a boom mic but in reality, the difference is much more about the application rather than tonal or audio quality.
Have you ever seen the mic operator on a film shoot? They are usually stood behind the camera holding an extremely long mic stand above their head while pointing it at the voice talent.
These are commonly known as boom operators, with the mic often just referred to as a boom mic. The pole (you guessed it!) is referred to as a boom pole.
The microphone attached to this pole is known as a boom mic, but in actuality, this just refers to how the mic is being used.
A Shotgun microphone is often attached to the pole for its rejection of off-axis background noise but by being placed onto the boom stand it essentially becomes a ‘boom mic’.
Another reason for using a shotgun mic in this scenario is it doesn’t require the operator to close-mic the actor (meaning you don’t need to be right up by the actor’s face to get a great sound, but you can still reject the surrounding ambiance).
This allows the boom operator to be able to hide the microphone from the camera’s view.
Of course, there are occasions where this slips through the net and you can find lots of videos online of boom poles and boom mics accidentally slipping into view for a split second.
A boom mic operator needs to be very dynamic on film shoots, particularly if shooting outdoors where the actor may be moving around a lot as they need to ensure the mic is kept in the right place the entire time to get a consistent sound. If the speaker’s head moves then the mic needs to follow.
Similarly, you may have seen shotgun mics being used for face-to-face interviews, often with an interviewer sitting opposite their guest.
The shotgun mic is usually boom-mounted, one for each participant, and the shotgun mic is pointed directly at them.
Because of the qualities of the mic, they can usually be kept out of shot but still sound great.
How does a shotgun mic actually work?
The way a shotgun mic captures the sound and helps reject off-axis sound is actually quite fascinating.
A shotgun mic can be referred to as an ‘interference tube’ due to the way it’s designed.
You might assume the actual capsule of the mic (the part that translates the sound to an electrical signal) is located at the end of the microphone but in fact, it’s actually found about halfway down the tube.
This microphone then has a series of slots along its length that allows the sound source you want to record in, while those slots reject noise coming in from other directions through means of phase cancellation.
This means that the audio being picked up from the sides of the mic are predominantly canceled out whilst the audio from the center remains clear and crisp.
Because these sound waves interfere with each other we get the name ‘interference tube’.
So as you can see it’s not that the shotgun mic isn’t picking up any sound at all from the off-axis, but rather it’s using an audio phenomenon to disperse it which results in the tight polar pattern the mic is famous for.
If you’re struggling to understand how phase can affect a sound source check out our article on phase reversal.
Shotgun mic pros and cons
Whilst there are some big benefits of using a shotgun mic (depending on the recording scenario) there are some downsides to consider.
The first is that your shotgun mic will usually need phantom power to operate.
Now, this isn’t really a huge issue as most interfaces will offer at least one channel with phantom power, but if you’re going to be recording on the go it’s worth considering that you’ll need a power source.
Another consideration is that you’ll need to be on the ball with your shotgun mic when recording dialogue.
The off-axis rejection is superb for capturing a clean take of your sound source, but if your sound source (for example an actor) is moving around a lot, you’ll need to make sure the mic stays on them throughout.
If you’re using a boom as well, you’ll likely need another set of hands to help out with the recording.
There is an additional risk of picking up wind noise with a shotgun mic although this can be offset by using a wind muff. Often a lavalier mic can be an alternative to a shotgun mic for this reason.
There are some great options out there for mounting a shotgun mic directly onto a camera if you’re vlogging or just recording yourself, or someone up close this is a solid option that doesn’t require a hefty boom mic and complex recording setup.
Shotgun Vs lavalier mic
In a similar way, lavalier mics are commonly used for recording dialogue on television shows or interviews.
You’ll probably have seen one attached to a presenter’s shirt or jumper as they can be an easy and simple way of recording in the same way as a shotgun mic. Whilst they serve the same purpose they are very different types of microphones.
For example, a lavalier mic will pick up a much larger range of ambient sound than a shotgun mic, however, being able to clip the mic onto a presenter’s clothes means the mic will remain correctly positioned without the need for constant readjustment like with a shotgun mic when the person starts to move.
Of course, if it’s an actor you are recording then a lavalier mic probably isn’t the best solution (imagine recording a drama set in the 1920s and the main character has a modern mic attached. It won’t look very good!).
Lavalier mics can be hidden inside clothes, but again this isn’t always a reliable solution as the mic can easily pick up the noise of the person’s clothes rubbing against it which will be impossible to remove in post-production.
As you can see, both a shotgun and lavalier mic have pros and cons so it’s important to think about the setting you are using them in.
As with anything in audio production, preparation and considering what you’re recording, where you’re recording it, and the desired outcome are crucial.
Shotgun mics can be a great solution for eliminating unwanted ambient noise and using a boom arm means you’ll be able to get a great take without the need for any microphones or equipment to come into shot.
Shotgun mics are also great for vlogging and for mobile recording where you don’t necessarily even need a boom.
Of course, there are scenarios where condenser, dynamic, or even binaural mics are more suitable for your productions. But if you’re likely to be recording dialogue (outside or inside) a boom-mounted shotgun mic is often the best solution.