Ever watch a low-budget movie and wonder, “How did this film make the cut?” The cinematography may have been average, the story derivative but — the sound! The quality of the sound design may be the reason the film made it onto the screen. Surprisingly, many film festival programmers rate sound quality as the element they weight most heavily when looking at entries. In fact, sound in film can be very deceptive.
Techniques that many films use–such as audio editing, ADR (automated dialog replacement, also known as dubbing or looping), remixing and sound sweetening–occur in post-production and can be very time-consuming as well as expensive.
For most productions, it’s important to get audio right the first time — although it’s equally as important to have reasonable expectations about the type of sound you can obtain with the right gear in specific types of environments.
There are several basic types of microphones you can use in production.
Whether wired or wireless, handheld microphones are held by an interviewer or talent. They’re great for getting run-and-gun interviews in noisy environments where you don’t have the time for a lavalier. Handheld mics can also be used on a stand to pick-up audio from a subject who will not be moving around. Handheld mics can deliver a very rich full sound. However, if you don’t want your microphones to be seen in your shots, a lav or shotgun mic would be a better option.
This tiny microphone is typically clipped to a lapel or shirt, but sometimes it can be completely concealed under the talents’ clothing. Lav mics come in both wired and wireless forms. Lav mics can be helpful at times in blocking outside noise because of their close placement to the sound source; however, the noise created by your subject’s clothing moving around while wearing a lav can make the audio captured by the microphone unusable. Lavalier mics typically don’t produce as rich of a sound as handheld or shotgun mics. If it’s possible, using a shotgun mic instead of or in addition to the lav would often be a better choice.
This long, thin type of microphone can be mounted to a stand, boom pole or your camera rig. Shotgun mics can be placed much further away from your subject than lavs or handheld mics, while still doing a good job at rejecting outside noise. Shotgun mics are sensitive to handling noise, however, which can make using one mounted to a camera rig or even on a boom pole challenging.
Microphones in Post Production
Microphones used for ADR or narration vary from handheld mics to large condenser mics. While many have XLR outs to connect with pro audio gear, many are now being built to connect directly to computers via USB. Foley — the background sounds in film and TV productions — is often recorded with a large variety of mics depending on many variables, including whether the recording is in a studio or outside and what the desired sound is.
Tech Specs to Consider
This is a quick and dirty breakdown. It’s important to note that audio recording is an art unto itself, similar to cinematography. Many chapters of many books have been written about types of microphones, construction of mics and their pickup patterns.
Condenser vs. Dynamic Mics
The way a microphone element or capsule is built to pick-up sound affects how it performs. There are many types of microphone elements; however, due to cost, durability and function, there are only two that should be considered for production and post: condenser and dynamic.
In the most basic sense, condenser microphones use electrical current to power a series of plates that vibrate when sound waves hit them. The obvious con to this type of microphone is that it needs power at all times in order to work. Phantom power is used in pro audio systems to send power down the microphone cable to condenser mics without interfering with the audio signal. Otherwise, the mic will need a battery.
Condenser mics can be very sensitive, allowing them to pick up audio from a distance. A good example of this use is shotgun microphones. This same sensitivity can result in a condenser mic picking up a lot of extra wind noise and background noise, which is why a good windscreen is also a vital accessory for your shotgun mic. It’s also important to note that condenser mics can be a bit delicate.
Dynamic microphones use an electromagnetic coil and diaphragm. While that may sound a lot more delicate than a condenser, it’s not. Dynamic microphones are the most rugged mics available. They do have a limited sensitivity, which actually is not always a downside; however, dynamic microphones are usually not found with as tight of a polar pattern as many condenser mics have.
Polar patterns, also commonly known as pickup patterns, are the areas that a microphone will be sensitive to sound. The common polar patterns used in production recording mics are omnidirectional, cardioid, hypercardioid, supercardioid and line. Some microphones can even switch between polar patterns.
An omnidirectional mic has a polar pattern that is round in shape, while a cardioid polar pattern is heart shaped. The line polar pattern used for shotgun mics is almost completely in front of the mic and very directional. This helps explain the shotgun’s rejection of noise along the sides of the mic and its popularity for use on film shoots.
Cardioid and hypercardioid are commonly used for lav and handheld mics. They offer a good balance between wide pick up and rejection of outside noise.
Frequency response is perhaps the most overlooked element when shopping for a new microphone. Frequency response is a measurement of the audio frequencies, usually expressed in Hertz (Hz), that a microphone is most sensitive to. Each model of microphone will have a different frequency response and you’ll have to keep in mind how you plan to use it. For example, if you’re only recording spoken word, then you only need a microphone that has good reproduction down to around 75Hz since most people’s voices when speaking are not any lower than that. On the other hand, many audio engineers feel that accurate reproduction of up to and in excess of 15,000Hz (15kHz) is important for good intelligibility and a feeling of clarity of the spoken word.
Wireless vs. Wired
As a rule, wired microphones are more reliable than wireless; wireless always runs the risk of having radio frequency interference. There are new wireless systems that help eliminate many of those interference issues, making the difference more about money. Wireless systems are typically much more expensive.
Choosing the Right Mic
The right mic for the job may be using more than one microphone. For instance, say you’re doing an interview on the sideline of a football game using a handheld mic, and you can hear the subject holding the mic but not the crowd behind him. If you see the crowd making a lot of noise behind the subject of the interview, but you can’t hear the crowd making noise, it’s going to be rather awkward for viewers to watch. In this case, record from a pair of microphones. Use the built-in mic your camera might have or a built-in mic in a portable audio recorder to pick up the crowd and your handheld mic to pick up your subject. This will allow you to have a sense of ambient sound to your location without overpowering the track from your subject in your mix.
The right mic is only half the job.
Once you’ve determined the right mic(s) for a job, you’ll need to focus on microphone placement. There are entire books that have been written on microphone placement for recording. Taking the time to learn mic placement techniques will likely improve your audio more than better gear.
Mics and Money
It’s often thought that if a product is harder to make or made of materials that cost more, this will drive up the price. This can be true for microphones, but there are other factors that affect price. Like many products, mics made in Asia tend to be less expensive than many made in Europe or North America. Another factor that’s often overlooked is how common a mic or mic type is. The more popular a style of microphone is, the less expensive it’s likely to be.
The Azden SMX-30 is a video microphone with both mono and stereo capabilities, offering two separate capsules for switchable function. Have some dialogue to capture? Put it in mono mode and you will have a camera-mounted, super-cardioid shotgun mic. Need to capture the atmosphere for your scene to come alive? Switch it to stereo mode and you’ll record a stereo image with 120 degrees of coverage via two cardioid mics working in tandem. With a frequency response of 40Hz to 20kHz, this camera-top mic connects via a 3.5mm stereo mini plug and is powered by two AA batteries or phantom power.
Røde VideoMic Pro+
The VideoMic Pro + is a camera-mounted shotgun mic. It has a 3.5 millimeter mini-jack output with a detachable cable that also supports dual mono output. Also featured is a 20Hz to 20kHz frequency response and a Rycote lyre shockmount. New to the VideoMic Pro + is the addition of a safety channel that records at 10 decibels lower to give you more headroom if your subject happens to get loud quick. It has a high-frequency boost and a selectable 150 hz or 75hz high-pass filter. Lastly, the included rechargeable Li-Ion battery can sustain over 100 hours of use before needing to be recharged.
Sennheiser evolution wireless 100-p G4
An update to the industry-standard evolution wireless mic system series, Sennheiser claims that the user interface of the 4th-gen ew 100-p series will allow for faster set-up and better control thanks to 12 compatible frequencies. Additionally, the ew 100-p output power goes up to 30 mW. The housing for the SKM 100 G4 has also been made with lighter aluminum for easier use.
Included in the latest ew 100-p series offerings are a 135-p G4 Portable Handheld Set and two Portable Lavalier Sets, an ew 112-p G4 (omni), an ew 122-p G4 (cardioid). Also available is the ew 100 G4 ENG Combo Set, which offers both plug-on and bodypack transmitters with an omni-directional ME 2-II clip-on microphone. The new systems are compatible with all previous evolution wireless systems.
The Tascam TM-2X is a camera mountable stereo condenser microphone. It uses two capsules that are arranged in an XY pattern and features switchable sensitivity as well as a low-cut filter. The TM-2X can swivel up to 180-degrees and connects via a 3.5mm jack.
Samson Go Mic Mobile
The Samson Go Mic Mobile is a 2.4 GHz digital wireless mic system touting low latency audio transmission which promises to eliminate video sync issues, making it a good choice for filmmakers and video producers. The dual channel receiver can mount either to an Android or iOS smartphone or to a camera via its cold shoe adapter.
The Go Mic Mobile is available in three different wireless configurations: a handheld mic, a lavalier mic with beltpack or a shotgun mic. Flexible audio output options include switchable ⅛-inch headphone/line and USB audio outputs with volume control.
The Azden SGM-250 shotgun microphone, measuring in at 250 millimeters or about 10 inches, is designed to fit nicely atop DSLR cameras when needed while still providing super-cardioid directionality and good side noise rejection. Offering a frequency response of 20Hz to 20kHz, the SMG-250 features a low-cut filter and can be powered with either a AA battery or phantom power.
This year marked the 50th anniversary of the SM58 wired handheld mic, long known as one of the world’s most rugged and affordable professional dynamic microphones. The SM58 is a cardioid mic with a frequency response of 50Hz to 15kHz. As a wired mic, it retails for $100 and you can get a wireless kit with an SM58 capsule for $500.
Blue Microphone Yeticaster
With the Yeticaster, Blue takes their popular Yeti USB microphone and combines it with a Compass Premium Broadcast Boom Arm and Radius III Custom Shockmount to give video producers a pro setup for studio recording or live streaming. The Yeti features Blue’s proprietary tr-capsule technology along with four different pickup pattern settings and controls for headphone volume, mute and microphone gain.
The AT8015 is an 18-inch long, condenser, Line + Gradient pattern shotgun mic. The mic has a range of 40Hz to 20kHz and has a very narrow pickup pattern for good side noise rejection. The AT8015 can run on phantom power or a AA battery and retails for $300.
AKG C214 Large Diaphragm Microphone
The C214 is a cardioid condenser microphone built for capturing rich vocals. It’s great to use in ADR, narration and voice-over recording work. The C214 has a 20Hz to 20kHz range and a built-in 20db pad. Retailing for $400, the mic comes with a suspension mount and a metal case.
DPA Microphones SCO61-N Necklace 4061 Microphone
This lavalier from DPA is unique in that it’s mounted on a soft rubber necklace, eliminating the need for a clip. It features a 20Hz to 20kHz range and an omnidirectional patterned condenser capsule. The 4061 microphone can be adapted to XLR for wired use or for use with most major wireless kits. It retails for $530.
Sennheiser AVX-ME2 Wireless Lavalier Kit
This wireless lav kit comes with an on-camera receiver and small belt pack. The included ME 2 lav has an omnidirectional condenser capsule with a 30Hz to 20kHz range. The real standout feature with the AVX series wireless kits — both lav and handheld — is the way they deal with frequencies. With a traditional wireless kit, if you started to get interference on the channel you were using, you would have to interrupt the recording and change channels on both the receiver and the transmitter. The AVX series handles any needed frequency changes automatically without interrupting the flow of audio to your recording device. The AVX-ME2 kit retails for $700. The AVX-835 kit, which comes with a handheld mic, is $800
Many microphones require accessories such as a windscreen, pop filter, zeppelin, shock mount or even a boom pole. Purchase them with your mic so you don’t find yourself facing an overnight shipping situation. Remember that proper placement of your new microphone can make a huge difference; don’t settle for acceptable audio when you can have sensational sound.
DPA Microphones Inc.
Nady Systems Inc.
W. H. Bourne is an award winning documentary filmmaker. She is currently in post on her first narrative feature.