If you’ve ever seen behind-the-scenes footage of television or movie shoots, you may have seen a boom microphone at the end of a long pole being held above the actors. If you have a keen eye, you may have even seen a boom mic (accidentally) peak down into frame in your favourite TV show or movie!
What is a boom microphone? A boom mic has a highly directional polar pattern and is positioned at the end of a boom pole. These mics are staples in film and video. They are highly directional (pick up sound where they point to and reject off-axis sounds). Boom mics are often held by an operator, making them movable during a performance.
Let’s define boom mics in further detail, discussing their applications as well as sharing some common boom mic examples.
What Is A Boom Microphone?
In the broadest of definitions, a boom microphone is any microphone that is attached to a boom.
What is a microphone boom? The term mic boom typically refers to a boom pole that holds a microphone at one end and is held out-of-frame in film settings. However, mic booms also refer to the parts of mic stands that extend in the horizontal plane.
So then, in our broad definition of a boom mic, many microphones fit the description.
In general, when people in the audio and film industries talk about a boom microphone, they mean the microphone used in video production.
Shotgun boom mics work amazingly well in the world of film/broadcasting and are rarely used in other fields that require audio.
This boom microphone has a shotgun/lobar directional pattern. This means the microphone is highly directional, capturing sound in the direction that is point while rejecting most of the sound coming from other angles.
For a deeper understanding of the shotgun/lobar polar pattern, check out my article The Lobar/Shotgun Microphone Polar Pattern (With Mic Examples).
The boom mic is attached to the end of the boom pole, which is held (by an operator or heavy stand) so that the microphone is positioned just outside of the video frame.
For the best results, the boom mic is pointed at the actors or sound sources that are making sound and is subtly repositioned as this sound source changes.
For more information on holding a boom pole and boom microphone, check out my article How To Properly Hold A Boom Pole And Microphone.
Boom Microphone Applications
If we broaden our definition of what a boom mic is once again, we will have 3 main boom mic applications:
- Film and video dialogue and location audio recording.
- Studio overhead microphones.
- Stage overhead microphones.
Boom Mic Application 1: Film/Video
The most common application of a boom mic (and what most people think of when thinking of a boom mic) is its usefulness in film and video.
As mentioned in the earlier section of this article, shotgun pattern boom mics are a staple in the film industry. Here are the reasons why:
- They are highly directional which means they pick up sound only where they point.
- They are relatively robust and lightweight which makes it easy to attach them at the end of a boom pole and hold them in position.
Here are some general tips for using boom mics in film/video:
- Get a boom pole with an internally coiled cable if possible. If not, then ensure the mic cable is held tight or wrapped a few times along the length of the boom pole. In other words, keep the cable tight to the pole.
- Hold the boom mic as close as possible to the sound source without risking it appearing in the frame.
- Turn the microphone gently to ensure it’s pointing at the current sound source.
- Take breaks and stretch when you can if you’re the boom operator responsible for holding the microphone in position.
- If the talent/actor is stationary during a long shoot, consider holding the boom mic permanently in place by inserting the boom pole into a heavy stand or by attaching the boom mic at the end of a microphone boom stand.
Boom Mic Application 2: Studio Overheads
Stationary boom mic setups are commonly used in the studio (particularly to hold drum overhead microphones).
Although this application is not typically what we consider to be a “boom microphone,” it is, ultimately, a microphone on a boom stand.
Studio overheads are generally used for recording drum kits. They involve microphones in boom mic stands. The stands are footed outside the drum kit and their boom arms extend over the kit so that the microphones can be positioned directly above the drum kit.
For my drum overhead microphone recommendations, check out my article Best Drum Overhead Microphones.
Boom Mic Application 3: Stage Overheads
Booms are often used on stage to hold overhead microphones. This is true of the aforementioned drum overhead setup, but also may apply to hiding microphones overhead in theatrical performances.
Boom Microphone Examples
Although we’ve mentioned a broad definition for boom mics, I’ll only share examples of the typical boom microphones for film purposes.
3 film boom microphone examples are:
- Schoeps CMIT 5U
- Sennheiser MKH 60
- Rode NTG-2
Schoeps CMIT 5U
The Schoeps CMIT 5U is a top-address small-diaphragm shotgun microphone with a supercardioid capsule and shotgun polar pattern (due to it long interference tube). It measures 251 mm long and has unusually low colouration of off-axis sound for a shotgun mic.
The Schoeps CMIT 5U is an expensive microphone and is not necessarily an “industry standard” boom mic. However, it performs excellently in boom mic applications and definitely deserves a shout out here.
The CMIT 5U is lightweight, making it an excellent mic for booming on film/video shoots.
Sennheiser MKH 60
The Sennheiser MKH 60 is marketed as a “lightweight short gun microphone.” It is a small-diaphragm RF condenser microphone with a hypercardioid capsule and shotgun polar pattern (due to its interference tube).
The Sennheiser MKH 60 (along with the other mics in the MKH series) have become “industry standard” boom mics. This is due to their high-quality sound and largely due to their relative resistance to moisture. The humidity resistance is a much enjoyed characteristic of RF condenser mics.
This highly directional mic measures 280 mm. Like most shotgun microphones, the MKH 60 works great as a boom mic.
The Rode NTG-2 is a small-diaphragm shotgun microphone with a hypercardioid capsule and shotgun polar pattern (due to its interference tube). It’s lightweight and measures 180 mm long
The Rode NTG-2, like the other mics in the NTG series, are budget-friendly “industry standards” in film and video.
Cardioid Boom Mics In Tight Spaces
It’s worth noting here that when boom miking in tighter spaces or whenever you’re required to hold the microphone near a surface (ceiling, wall, etc.), it’s often better to use a cardioid pencil microphone rather than a shotgun microphone.
The rear lobe of sensitivity in the typical shotgun microphone will capture the reflections from the wall and may cause a sort of comb-filtering effect, which would thin-out the audio.
Cardioid microphones, on the other hand, do not possess this rear lobe of sensitivity and will therefore reject much of the surface rejections. This, of course, results in less comb filtering and a truer sound (at the expense of slightly less directionality).
What is the difference between a boom mic and a shotgun mic? A boom mic is, by definition, any mic at the end of a boom pole. Shotgun microphones are highly directional mics with hyper or supercardioid capsules and interference tubes. Boom mics are typically shotgun mics, but shotgun mics are used in more applications than just boom miking.
What does the fuzzy thing on a microphone do? The fuzzy thing that goes over a microphone is technically referred to as a windscreen, though is most often called a “dead cat” in the film/broadcast industry. Dead cats effectively minimize the wind noise around a microphone which yields a cleaner mic signal in less-than-ideal miking environments.
For more information on windscreens and dead cats, check out my article What Are Dead Cats And Why Are Outdoor Microphones Furry?