When capturing audio for film, it’s nearly always critical that the microphones remain hidden within the frame or stay out of frame. Boom microphones (the mics at the end of boom poles that point downward from above the frame) provide a very common method of capturing audio on film sets.
So which microphones work best as boom mics on film sets? After having spent some time working as a boom operator, field audio technician, and post production audio mixer, I have three top choices. My top three boom mics for film are:
- Schoeps MK 41/CMC 6: The Schoeps MK41/CMC 6 (link to check the price on Amazon) is a high-quality professional supercardioid microphone that gets the top recommendation as a film boom mic. The supercardioid MK 41 capsule isolates the person talking with no colouration while the CMC 6 preamp boosts the signal with clean gain and pristine accuracy. This microphone
soundas if you were there on set. The quality of the Schoeps MK 41/CMC 6 comes at a high price,but is definitely worth your consideration.
- Audio-Technica AT897: The Audio-Technica AT897 (link to check the price on Amazon) is an industry favourite with a very affordable price point. It’s the microphone I personally use most often when operating a boom mic on set. The 897 is a classic shotgun microphone with an extended supercardioid pattern for excellent directionality and maximal rejection of side noise. When choosing a film boom shotgun mic, the affordable AT897 should be one to think about.
- Sennheiser MKH 60: The Sennheiser MKH 60 (link to check the price on Amazon) is an incredible boom microphone. This “short gun” is a shotgun-type microphone but with a shorter interference tube. It is also an RF condenser microphone, which explains its extremely low self-noise and immunity to moisture.
Before getting into details about each of these microphones, let’s shortly discuss the criteria in which I’ve based my recommendations on.
What Makes A Great Boom Microphone For Film?
- Extreme directionality: Choosing a highly directional microphone is ideal for booming in film, where the idea is to capture the cleanest sound of a talent/subject as possible. Shotgun/Lobar mics provide extreme directionality with great off-axis rejection, helping to capture where the mic is pointing while rejecting everything else.
- Lightweight: Select a lightweight microphone for the end of your boom pole. When operating a boom mic/pole for any length of time, the microphone/blimp weight at the end of the pole plays a big role in the comfort and performance of the boom operator.
- Shape: Pick a microphone that fits nicely into a shock mount and blimp style windscreen. This ties into choosing a shotgun mic, since most shotgun mics are designed to fit with boom poles, mounts, and blimps.
- Flat/extended frequency response: Using a boom mic with a flat frequency response across the human range of hearing yields a natural sound. It’s better to filter out low-frequencies in the mix than to not have them at all in the recording.
- High sensitivity: Choosing a boom mic with high sensitivity is important when shooting film. The boom mic will be likely be shielded with a blimp and windscreen between the mic capsule and the talent/subject. The boom mic will also be some distance from the talent/subject (at least out of frame). A sensitive directional mic will easily overcome the above issues.
Related reading: How To Properly Hold A Boom Pole And Microphone.
Now let’s discuss each of the three mics in more detail, focusing on the above factors.
The Schoeps MK 41/CMC 6
So my top recommendation for a film boom mic is not a shotgun, which is industry standard. Why do I recommend the Schoeps MK 41/CMC 6 over any “traditional” shotgun mic for booming on film sets?
The answer to this lies in the capsule piece of this combination: the MK 41.
The MK 41 is a high-quality supercardioid condenser microphone capsule. Similar to a typical shotgun mic, the MK 41 is highly directional. Sounds from the sides and rear of the capsule are strongly attenuated. This reduces the amount of off-axis sound, noise, and diffuse reflections from the acoustic space in the mic signal.
The top-of-line design of the MK 41 does all of this with practically no off-axis colouration. Every sound from every direction, regardless of the attenuation, is picked up with equal frequency response. This cannot be said for any interference tube shotgun microphone.
Because the MK 41 does not require an interference tube for its directionality, it also has the added bonus of being able to get physically closer to the talent or other sound source on a film set.
Powering the MK 41 and CMC 6 is done with standard +48 V DC Phantom Power.
For more information on powering microphones, check out my article Do Microphones Need Power To Function Properly?
With that short primer, let’s get into the specs of the MK 41/CMC 6 that make it my number one recommendation as a film boom microphone.
Directionality Of The Schoeps MK 41/CMC 6
As mentioned in the opening, the MK 41 is a very consistent supercardioid capsule. Here is the MK 41’s polar pattern graph:
For more information on the supercardioid microphone polar pattern, check out my article What Is A Supercardioid Microphone? (Polar Pattern + Mic Examples).
As we can see, the MK 41’s polar pattern is highly directional and extremely consistent across its frequency spectrum.
When booming on a film set with the MK 41/CMC 6, keeping the subject within 60° will yield fairly consistent results (a 3 dB difference is just barely noticeable). The above graph shows the amount of attenuation that will happen to room reflections and off-axis sounds. Such attenuation yields a clean, dry signal in the direction the microphone points.
Weight Of The Schoeps MK 41/CMC 6
The Schoeps MK 41/CMC 6 combined weight only 77 g (2.7 oz).
- The MK 41 weighs 17 g (0.6 oz)
- The CMC 6 weighs 60 g (2.1 oz)
That makes this microphone very easy to hold in place at the end of a boom pole for an extended period of time. This may not seem like a big deal initially, but after hours of shooting, the boom operator’s shoulders, back, and neck will be thankful that the microphone on the other end of the boom pole is only 77 grams.
Shape Of The Schoeps MK 41/CMC 6
The Schoeps MK 41/CMC 6 has a cylindrical shape with a length of 138 mm (5.43″) and a diameter of 20 mm (0.79″)
- The MK 41 measures 22 mm (0.87″) length x 20 mm (0.79″) diameter
- The CMC 6 measures 116 mm (4.57″) length x 20 mm (0.79″) diameter
The MK 41/CMC 6 is cylindrical just like the interference tube shotguns that are common as boom mics on film sets. However, because the MK 41/CMC 6 does not require an interference tube, it’s much shorter and can positioned that much closer to the talent or sound source (improving the signal-to-noise ratio of the mic signal).
Frequency Response Of The Schoeps MK 41/CMC 6
The MK 41 capsule, when feeding its signal through the CMC 6 active amplifier, has a frequency response range of 40 Hz – 26 kHz. That extends beyond the range of human hearing. Here is the MK 41/CMC 6 frequency response graph:
Here we can see the beautifully flat response of the MK 41/CMC 6. A frequency response that captures the sound around it with astonishing clarity.
However, we see a slight roll-off in the low frequencies and the lower range stops at 40 Hz (though the human hearing range extends to 20 Hz). This typically isn’t a huge deal on film sets. There isn’t a lot of information in the first octave of human hearing (20 Hz – 40 Hz). Human speech rarely has any information below 40 Hz.
So instead of negatively affecting the sound, what this low end roll-off does is it gently reduces the amount of low-end rumble, electromagnetic interference, and low-frequency ambient sound that would otherwise find itself in the microphone signal.
For more information on microphone frequency response, check out my article Complete Guide To Microphone Frequency Response (With Mic Examples).
Sensitivity Of The Schoeps MK 41/CMC 6
The Schoeps MK 41 has a sensitivity rating: -36 dB (V/Pa), 16 mV/Pa with CMC 6. This is a high sensitivity rating, which means that the microphone will output a strong signal when subjected to sound.
For more information on microphone sensitivity, check out my article What Is Microphone Sensitivity? An In-Depth Description.
The microphone will typically be encompassed by a blimp-style windscreen of sorts. A high sensitivity allows the mic to effectively pick up on the sound vibrations that pass through the blimp walls and reach the mic capsule.
The MK 41 also only has a self-noise of 14 dBA with CMC 6. This is unnoticeable in any practical film set and even in most audio recording booths.
For more information on microphone self-noise, check out my article What Is Microphone Self-Noise? (Equivalent Noise Level).
The Audio-Technica AT897
The Audio-Technica AT897 is an industry favourite shotgun microphone for boom applications in film. This line+gradient (lobar polar pattern) condenser mic can run on 1.5V AA batteries or on Phantom Power. The AT897 is built to last and comes with its own shock mount and windscreen.
A short interference tube reduces the length of the AT897, allowing for closer capture of the intended sound as well as direct camera mounting with little risk of the microphone appearing in frame.
The AT897’s narrow acceptance angle makes it an excellent choice for capturing specific audio sources on a film set. Simply point to the mic at the talent or subject you want to record.
Let’s talk about the specifications of Audio-Technica AT897 that make it such an awesome film boom mic.
Directionality Of The Audio-Technica AT897
The Audio-Technica AT897 has a line + gradient polar pattern, making it highly directional. Here is the polar pattern graph of the AT897:
The graph shows us the extreme directionality of the AT897 shotgun mic.
For more information on the lobar/shotgun microphone (line + gradient) polar pattern, check out my article The Lobar/Shotgun Microphone Polar Pattern (With Mic Examples).
We see that the 897 does an excellent job rejecting sound from the sides and rear, though there is a bit of a rear lobe of sensitivity at 200 Hz. This rejection is ideal when booming since we cannot get the mic too close to the talent (otherwise the boom would be in frame). Highly directional mics like the AT897 allow us to focus in on sound sources from a further distance.
Another thing worth mentioning about the AT897 is that, compared to the aforementioned Schoeps MK 41/CMC 6, the 897 has a very coloured off-axis response. So although the AT897 does an excellent job in attenuating off-axis sounds, the little bit of signal that it does produce from off-axis sounds will be coloured. This different in frequency response between on and off-axis sounds may cause the mic signal to sound a bit unnatural if the off-axis sounds are loud enough.
Weight Of The Audio-Technica AT897
The AT897 is very light weight, weighing only 145 g (5.1 oz). This is relatively easy to hold at the end of a boom pole for extended periods of time during film shoots.
Shape Of The Audio-Technica AT897
The AT897 is a shotgun mic that measures 279.0 mm (10.98″) in length and 21.0 mm (0.83″) in diameter. It will fit in most standard long film boom windscreens.
Frequency Response Of The Audio-Technica AT897
The frequency response of the Audio-Technica AT897 is rated as 20 Hz – 20,000 Hz. It features a low-end roll-off switch (high-pass filter) at 80 Hz, 12 dB/octave. Here is the frequency response graph of the AT897:
We see that the AT897 has a relatively flat frequency response. This is excellent for capturing a natural sounding audio recording, which is practically always a bonus when capturing film audio.
The boosts that happen in the presence range (3 kHz – 7 kHz) help to ever-so-slightly accentuate speech intelligibility. This is good news for booming on film sets since the majority of time, we’ll be capturing the speech of the actors.
The 80 Hz high-pass filter is a great option to have when recording on film sets. More often that not, the sub-80 Hz range isn’t all that important. It’s usually comprised mostly of low-end ambient noise, mechanically transmitted noise, and electromagnetic interference. If the boom mic is not directed to pick up low-end sounds, the signal will usually benefit from this low-end roll-off switch at 80 Hz.
For more information on microphone high-pass filters, check out my article What Is A Microphone High-Pass Filter And Why Use One?
Sensitivity Of The Audio-Technica AT897
The Audio-Technica AT897 has slightly different sensitivity ratings depending on how it’s powered:
- Phantom: –40 dB (10.0 mV) re 1V at 1 Pa
- Battery: –41 dB (8.9 mV) re 1V at 1 Pa
These are relatively low values for a condenser mic, but the AT897 will output a fairly strong mic signal when subjected to sound pressure variation.
The real question here though has to do with how sensitive the AT897’s diaphragm is to sound waves.
The interference tube of the AT897 allows all on-axis sound frequencies to reach the diaphragm equally. However the tube causes greater off-axis attenuation in high frequencies than in low frequencies. This makes the AT897 more sensitive to low-frequencies off-axis than high-frequencies.
However, we mainly focus on capturing on-axis sounds. On-axis, the AT897 is very sensitive across the frequency spectrum, capable of effectively reproducing the nuances in an actor’s speech or the smaller details in any sound source. This makes the AT897 a top recommendation as a film set boom mic.
The Sennheiser MKH 60
The Sennheiser MKH 60 is an excellent boom mic choice on film sets and definitely deserves a spot on the recommended list. This RF condenser microphone is a popular choice for outdoor shotgun applications and works wonders in film as well.
What’s so special about RF (radio frequency) condensers?
RF condensers use a low RF voltage from a low-noise oscillator to polarize their capsules. As capsule capacitance varies, the RF voltage is modulated and a mic signal is created.
RFCs, generally speaking, have flatter frequency response, lower noise, and are better in weather than FET or tube condensers. This makes them excellent choices for film shoots both indoors and outdoors.
Let’s discuss the specs of the MKH 60 that make it such a great boom mic in film.
Directionality Of The Sennheiser MKH 60
The Sennheiser MKH 60, like many shotgun microphones, has a supercardioid/lobar polar pattern. The mic capsule itself is supercardioid and when combined with the interference tube, the mic takes a more directional lobar pattern.
Here is the polar pattern diagram of the Sennheiser MKH 60:
As we see in the above graph, the MKH 60 is highly directional and becomes more directional at higher frequencies. This is typical of directional microphones.
The MKH 60 does an excellent job attenuating off-axis sounds, which is part of the reason why it sounds so good in film. More direct sound (where the mic is pointing) and less indirect sound (everything else) is always a good thing when trying to capture the cleanest audio signal possible on a film set.
Weight Of The Sennheiser MKH 60
The Sennheiser MKH 60 weighs only 150 g (5.3 oz). Its light weight makes holding the boom pole relatively easy when the MKH 60 is on the other end.
Shape Of The Sennheiser MKH 60
The Sennheiser MKH 60, like all shotgun mics, is long and cylindrical mic. It’s made of a pencil microphone and interference tube. The MKH 60 is 28 mm (1.1″) in diameter and 280 mm (11″) long.
This microphone fits nicely in standard shotgun shock mounts and in long windscreens and mic blimps.
Frequency Response Of The Sennheiser MKH 60
The Sennheiser MKH 60, like most RF condensers, has a nice, flat on-axis frequency response. The response ranges from 50 Hz – 20,000 Hz. Here is the MKH 60’s frequency response graph:
Note that this graph is a representation of on-axis sounds, which is the axis we want to capture sound from. There is actually great colouration (along with attenuation) of off-axis frequencies as we had discuss in the directionality section.
So the MKH 60 has a very flat frequency response. This makes it sound very natural, especially in quiet environments when it is positioned to pick up on-axis sounds.
We notice two switchable options with the MKH 60:
- Roll-off filter: this switch activate a gentle roll-off starting at 1,000 Hz with a steeper roll-off of -6 dB/octave at 200 Hz. Rolling off the low frequencies will help reduce or eliminate low-end rumble and other mechanical noise. Pay attention to how it affect the sound of lower register voices as this switch may cause unwanted thinning of the actors’ voices.
- Treble emphasis: the switch activates a 5 dB high shelf boost that gradually rises from 1,000 Hz and settles around 5,000 Hz. This treble emphasis can help add extra shine to an MKH 60 boom recording, especially when a thicker windscreen is used to protect the mic.
All-in-all, this frequency response gives us practically everything we could want in a film set boom microphone (minus the extreme low end, which is rarely needed).
Sensitivity Of The Sennheiser MKH 60
The sensitivity rating of the Sennheiser MKH 60 changes with its optional -10 dB pad. The two selectable sensitivities are:
- 12.5 mV/Pa (-10 dB pad engaged)
- 40 mV/Pa (no pad engaged)
The pad will typically not be engaged during film recording unless the sound source happens to be above 125 dB SPL (the max SPL rating or MKH 60 without the -10 dB pad engaged). 40 mV/Pa is a high sensitivity rating, which works well for capturing strong mic signals on a film set. High sensitivity values are especially beneficial when the boom mic is inside a blimp or windscreen.
For more information on passive attenuation devices, check out my article What Is A Microphone Attenuation Pad And What Does It Do?
The condenser capsule of the MKH 60 is very reactive to sound pressure variation and allows for an accurate reproduction of sound as the microphone’s output signal.
A Note On Boom Microphone Shock Mounts And Deadcats
When boom miking on film sets, the boom microphones should sit inside some sort of shock mount that is fastened to the end of the boom pole. The mic and shock mount should then be encompassed by sort sort of protective blimp/filter screen. In outdoor shoots, an additional windscreen should cover the outer shel of the blimp.
I would highly recommend Rycote shock mounts and Rode blimps/deadcats.
Let’s talk about why these standards are well respected.
Shotgun mic shock mounts are practically mandatory for boom operation. Shock mounts mechanically isolate the sensitive boom microphones from the boom pole and boom operator. This means a massive reduction in the potential for mechanical noise to affect the mic signal.
Mechanical noise is unfortunately a common occurrence in boom poles, happening when boom ops changes their grip or if the XLR cable, at any point, pulls on or hits the boom pole.
When it comes to shotgun mic shock mounts, my top recommendations are:
For more information on microphone shock mounts, check out my article What Is A Microphone Shock Mount And Why Is It Important?
Blimps are the large protective shields you nearly always see on the end of boom poles. These blimps protect the boom mic and shock mount physically and provide some protection from wind.
It’s critical that blimps remain acoustically transparent and allow sound waves to travel to the mic capsule with little to no colouration.
My go-to blimp recommendation:
Dead cats (yes that’s an industry term) are the furry windscreen layers you’ll often see encompassing the blimps at the end of a boom mic. These windscreens provide must more protection than the blimps alone and are critical in outdoor filming.
The wind protection often comes at the cost of decreased acoustic transparency and a slight dampening of the higher frequencies before they have a chance to reach the mic diaphragm.
The aforementioned Rycote Super-Blimp NTG comes with a furry windjammer/dead cat.
My go-to dead cat recommendation:
For more information on boom microphones and windscreens, check out my article What Are Dead Cats And Why Are Outdoor Microphones Furry?
All In One
It’s always nice to have everything together in one nice package. Check out the Rode Blimp for an all-in-one shock mount/windscreen for you film boom microphones.
So there you have it, my top three recommendations for boom microphones in film are:
- Schoeps MK 41/CMC 6: My top recommended high-end boom mic for film.
- Audio-Technica AT897: A top recommended and very popular shotgun boom mic for film.
- Sennheiser MKH 60: Another top contender for quiet film sets and outdoor shooting.
For all the My New Microphone mic/gear recommendations, please check out my page Recommended Microphones And Accessories.