Audio for Video Part 2: Sound for Interviews
by Jeff McLain
One of the most common scenarios for independent filmmakers is The Interview. Interview footage and audio can make up the entire backbone of a documentary or news magazine story. Interviews are also peppered into wedding videography. And interview situations are used in narrative filmmaking as a story-telling element — whether it’s talking to Jim and Pam from The Office — or the zany characters in Christopher Guest's Spinal Tap or Best in Show — or an interview between Oprah and some celebrity. Interviews are a bread-and-butter scenario of the professional filmmaker.
If you missed my first article, "Audio for Video Part I: The Basics", please go read it here. Now that you know a little something about what sound is and how to gather it — let's think about the considerations of sound for interviews.
Treating the Room
Whenever you walk into someone’s home to conduct an interview, there are some immediate considerations. It may be the case that the room with the most space is the kitchen. People often want to sit at their kitchen table for an interview and the hard surface of a kitchen or dining room table will cause some reflections that your microphone can hear. These reflections will give a tinny or echoing sound to your interview and are difficult to fix in post-production. Kitchens are also loaded with hard surfaces — solid-surface countertops, cabinets, refrigerator, and appliances. All hard surfaces! And sound waves LOVE to bounce off these surfaces and provide the "empty hall" sound to your recorded track. The empty hall sound is what is called Reverb, or reflections — and they are easy to put into your sound as a special effect, but difficult or impossible to remove if baked in from the start. So, we always want to reduce them.
Another culprit in the kitchen is the refrigerator. Fridges like to hum and make ice and create a lot of mysterious noises that our microphones will hear. Luckily, fridges are a big cooler so they’ll keep their temperature for a while even if they are unplugged. So, one of my first tasks is to ask to unplug the refrigerator for the duration of the interview. An old trick that will help you remember to plug it back in afterwards is to leave your car keys in the fridge. You won’t forget them! Beyond the fridge, removing ticking clocks and surveying the appliances for any other potential noise-maker is a smart move. I’ve heard the sound of a ticking clock from many rooms away through my headphones.
If possible, move the person to a bedroom and frame the set-up in a pleasing way. The bed and drapes and other soft things immediately help to dampen the reflections of hard surfaces in a room. But, if the dining room or kitchen are where you have to be, get some sound blankets. Matthews, Angler and Filmcraft all make bonafide “sound blankets”. You can also use basic furniture pads for this as well with success.
Clamp the blankets around to the left and right of camera, on the floor around your subject, on the floor behind your subject and on the table surfaces around them to help minimize these reflections. If you can’t move the fridge to unplug it, cover it with several sound blankets to reduce the sound — and try to disable the automatic ice-maker if you can.
Microphones and Back-up Microphones
There are two schools of thought on this: Some folks prefer to put a boom microphone out over the interviewee, while others prefer to place a clip-on lavalier (lav) microphone on them. I prefer both at once! But let’s examine these methods.
The benefit of a lav mic is that you only have the lav mic, transmitter and receiver to worry about. It’s super lightweight and easy to transport. The drawbacks are that you must get a clip-on mic on your interviewee and they may be wearing noisy fabrics or move around creating noise into the mic. Some wireless systems can suffer dropped signals or have radio frequency interference (RFI). And, unless you get the microphone under their clothing or have skills in hiding lavalier microphones, the microphone will be seen. To have a backup to a lav mic would entail a second lav mic, which increases the complexity.
First, you must be suave and convince the interviewee of the need to wire them up. Some folks are not entirely comfortable with this, and some folks do not have the time for this. Regardless, I always try and get them wired up as a backup. I never consider it my main microphone though — it is my backup only. Further, if they are wearing poly-type fabrics, such as wind-breakers or poly shirts or jackets, the lav mic will hear so much of the "shoosh shoosh" of the fabric that it’s not worth it. Get them to remove that jacket if possible!
I’ve had some wireless devices that suffer from little audible 1 millisecond drop-outs when people nearby are using their cellphones — so that is a concern of the lower-end brands. In typical interview situations, many productions are okay with seeing the microphone. In narrative films and some documentary work, the mic is always hidden in clothing, under a hat, or in their hair.
If you are relying solely on a lav mic that is wired to a recorder on the interviewee and it dies, you won’t know it until the interview is over. If you are using a wireless lav set-up, you’ll notice, but if that’s the only mic option you have, the interview has been killed. Sometimes in live productions you will see two lav microphones attached to the same lapel clip — such as live debates or news anchors. These are high-pressure live events and you just can’t have a microphone going silent in the middle of that! It started with Walter Cronkite in the 1970s when his lav mic died on-air; after that he had two mics on his lapel.
Other issues may be that if you are using a wired mic-to-recorder and you can’t monitor the sound with headphones, you can’t make changes in the event of fabric noises or poor placement. But when you use a wireless set-up, you have the option to listen in on the recorded sound and you can pause the interview if things aren’t perfect, fix the issue, and continue.
For these reasons, my main microphone during an interview is the Sennheiser MKH 50 super-cardioid coming in from overhead on a boom pole. I attach this super-cardioid microphone to the boom and position the boom so it is not casting shadow on the subject from my key light. To do this, I nearly always bring the boom in from the opposite side as the key light, but this varies.
I’m careful to treat the room and to have the mic swung out of the way when my subject is entering and exiting the space, so they don’t forget about it and then bump their head! This serves as my main mic and avoids any scratchy clothing issues or wireless mic issues. Then, if I’m able to get them wired, the wire serves as my backup. It also gives me another choice in case I decide I like the lav mic sound better or if some other technical issue arises. Once I had an interview where my boom mic could hear a jet plane fly overhead — but the lav mic was not as sensitive to this and I was able to seamlessly punch in the sound from the lav mic in that section and hide the jet sound.
Wireless lav set-ups are very nice and provide not only some convenience to the production, but the ability to monitor the sound. Wireless transmitters are transmitting the audio signal as an ultra-sonic frequency back to your receiver which is plugged into your camera or a recorder, enabling you to plug in headphones and listen. In the image above, you can see my Sennheiser MKH 50 mic on the boom out over the subject, and our sound person is listening to both the boom mic and a lavalier microphone that is hidden under the shirt of our interviewee.
The Deity Connect wireless system is a nice solution because it does what is called Frequency Hopping, where if it senses a weak signal, it will hop to another frequency seamlessly. Pretty cool! I also like this system because I can adjust the transmitter’s settings remotely from the receiver rather than having to futz with settings on the transmitter and bother the interviewee to do so. If I’m filming a wedding, and the officiant is talking softly, I can raise the Gain on her transmitter from my receiver — that is super handy! However, with this unit, I have experienced some drop-outs when someone is using their cellphone in the region, most likely when they are trying to connect to local Wi-Fi networks. I simply ask everyone on-set to stay in Airplane Mode on their phones for the interview. The Deity system works on the very-crowded WiFi wireless band, so you must be diligent about getting everyone to go to Airplane Mode for the interview.
The Audio Limited, Zaxcom, and Lectrosonics brands are considered top-of-the-line and offer features that make their heavy price tags worth it. But for smaller sized productions, the Deity system or a system like the Sennheiser G4 series works fine.
Wireless has its inherent pitfalls, but it offers flexibility-of-movement and framing like no other. You can hide wireless mics on people, and it allows for much wider-angle framing where a boom mic would be in the scene. In most cases, the framing and story are going to dictate how you will gather the sound.
Some videographers prefer the simplicity of the Rode wireless system — while others prefer the Sennheiser wireless system. Some folks also prefer to connect the wireless receiver directly to the camera to negate any sync issues. It just depends upon your own level of scrutiny when listening to these tracks and how good your camera pre-amps are. You can put a nice microphone on someone and run that sound to your camera, only to have your camera preamps color that beautiful sound with a noticeable "hiss" sound — and that is a bummer! On your own productions this may be totally acceptable — but the reason the pros use the better gear is because they don’t want their files to have any avoidable problems.
Mixer / Recorders and Redundancy, a.k.a. “Second System”
When you go for the cheaper option, it often means that what you bought won't last long — and then you’ll need to buy another. Will it die on a shoot? Will you be in the field, far away from the ability to buy another? So, you spent $400 and then you have to spend $400 again and perhaps you’ll have to do that again. Or you’ll realize the limitations of your device and get a more-expensive version on the 2nd and 3rd go. Instead, I suggest you cry once and just get the more-expensive unit that will stand the test of time from the start.
Many people can’t fathom spending $3000 on a quality sound package to give themselves multiple backup options and redundancy along with premium sound quality. But they will happily spend $3000 on a camera for beautiful picture. But, in motion picture — SOUND is half the show!
Let’s assume you have decided that connecting sound directly to the camera as your main recorder is not good enough for you. Maybe you have done this and been burned and you want some backup options. Perhaps you had an event where your microphone’s receiver was plugged into the DSLR and the interview went longer than 29 minutes. Oops! A lot of these DSLR and mirrorless cameras will not record continuously longer than a half hour (at the time of this article anyhow). Therefore, not only did the camera stop recording, it stops recording audio. This is not a good situation because in many editing scenarios we can use B-Roll with the audio to cover up the fact that a camera stopped recording for a few seconds. But, if your audio stops, too — that’s not a good situation! Because of a variety of these reasons, you have decided going “second-system” is a good way to go. Second system means that the sound is being recorded externally, not to the camera. There are many options that run the gamut in price, quality, and flexibility.
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Just to get it out of the way: Sound Devices, Zaxcom, Cantar and Nagra brands are super high-quality, for the pros, and likely out of an independent videographer’s budget. If you’ve got the money, you won’t go wrong unless you get something that is more than you really need. Most of the top-end devices have bells and whistles meant for larger television and cinema productions and are overkill for indie-users. But, some of their pared-down units are worth a look, and you won’t go wrong with these brands.
The Zoom H4n series has been in use by student filmmakers for a long time. Personally, I have found their preamps to be noisy. I find the interface clunky to navigate and the manual to be overly confusing. This is often the case when they are cramming so many features into such a small device. The start-up time is very slow, which is a major problem for event videographers when you might be needing to hit "Record" right away to capture a toast, but the device is taking a full minute to start up. That’s not good! This device does not offer anything in the way of attenuated tracks, timecode, or any sort of decent Out cable to have a safety track recorded to camera — however, it is a micro-budget choice for sound recording. It will run on a “Stamina Mode” extending the life of your AA batteries — but it sacrifices sample rate to do this. Will most people notice? Probably not. But, again, it depends on the level of "professional" you are, and what expectations your clients have.
The Zoom H4n Pro claims quiet preamps and several other features which look promising but my experience with the first generation makes me wary of the next. Perhaps the Pro version has a fast start-up and improved upon its predecessor, but, again, cry once? Or cry multiple times? I have had direct experience with the Zoom customer service, which left a lot to be desired. Again, maybe they are improving in time. Zoom is looking to sell a lot of their handy recorders at a low price point — and with that there are corners that get cut, customer service being one of them… Makes me wonder what other corners are being cut to get the price so low. No doubt corners are being cut because if something goes wrong with your device, it is cheaper for them to send you a different one than to repair it. My Zoom F4 was having issues and they upgraded me to the F8n because that was easier than repairing it. (The high-end devices are repairable.) In the end, the H4n Pro would make a decent backup recorder, and a decent place to start if you like the size and price, but I wouldn’t trust it to stand the test of time, nor would I trust it if someone was hiring me to run sound on their production.
The Tascam DR-60mkII and DR-70 mixer/recorder would be a decent choice for those looking for something that is small, can be mounted under the camera and connect a scratch cable to camera, has XLR inputs for external microphones, as well as the safety attenuated tracks through its Dual-Record function. Attenuated tracks are duplicate audio tracks that are 12 decibels quieter — which is handy if someone’s volume is fluctuating from quiet to yelling. Or, in wedding situations, if one person is talking quietly with the handheld microphone, and then another more boisterous person takes the mic and is much louder!
The Tascam is affordable and has decent pre-amps, but they are not crystal clear. Its pitfalls would be that it runs on AA batteries and it eats through these pretty quickly. However, if you are in a place where you can plug into AC power, you can use this device plugged into the wall.
One benefit to running off battery is that sometimes the AC power coming out of an outlet is not clean and can transfer strange buzzing to the recorded file. I have had this happen to me when I used my DR-60 plugged into external power. The best option with external recorders is to plug them into a larger lithium battery cell that can power it all day.
The Sound Devices MixPre-3 II would be a solid choice and last a lifetime. It has super clean preamps, 32-bit float recording (check out this Youtube video about that) attenuated tracks and timecode built-in. Additionally, you could run a tape-out cable back to camera if you wanted a scratch track to camera. And Sound Devices is known for quality, reliability, and customer service. They aren’t the cheapest device and that’s because they are workhorses and are trusted by professionals to keep working under some harsh conditions. Most likely you could buy one and not need another your whole career — just depends on what features you need as your productions evolve.
The usability of the Sound Devices recorders is excellent. I upgraded from a Zoom F8n to a Sound Devices MixPre-10 II and the user-functionality of the Sound Devices is excellent. I was up and running and navigating the device quickly — whereas I find the Zoom devices a bit harder to navigate quickly to get to important menus. I also find the knobs on the Zoom devices to be small and you have to bounce between Gain and Fader in a slow and non-intuitive way — whereas Sound Devices has this figured out.
Many of the newer mixer/recorders will write the files to two SD cards simultaneously, which is critical because SD media can go bad and you want to make sure that you have the files at least on the other card! Some devices like the MixPre series allow you to have files copy to a flashdrive that is plugged in to the machine.
The MixPre-10 II and the Zoom F8n have Left and Right stereo Out ports, which gives me the option between either running a cable directly to camera — or using a wireless transmitter to send the audio signal to a camera.
If the camera only has an 1/8” port, I can run a cable out of the MixPre10 II’s Aux Out or the F8n’s Sub Out 1/2 for this scratch track.
Being able to gather the sound with the mic, send it through the recorder, and then send it out of the recorder and back to camera gives me some fail-safes; I’m recording it to an SD card and a backup SD or flashdrive, and I’m also recording the sound to the camera!
Some mixers utilize what is called a Breakaway Cable, which is a cable that sends sound from Mixer-to-Camera, but has a return 1/8” cable that allows the sound person to "listen in" on what is being recorded to camera. The silver connection connects to the mixer, the double XLRs (red and blue) connect to the camera and the 1/8” cable plugs into the camera’s headphone jack to "return" the signal to the sound person. The black connection at left allows the operator to disconnect the mixer from the camera when they need to move around, adding flexibility.
The cheapest method to sync video to audio is to roll audio, roll camera, and then clap in front of your interviewee — or you can have the interviewee clap. The trick is to make sure all cameras that are rolling see the clap — so having them do it can be a bit messy if they aren’t skilled at clapping. You’d be surprised!
You can also use a basic slate. These are nice because it gives a nice crisp clap, as well as some actual information about the take number or camera file or whatever will help in the edit.
There are apps for phones and tablets that are digital slates, and those can be handy, too — but with all the problems of cellphones on-set, it’s just one more gadget to keep powered up, versus the analog simplicity of a plastic or wooden slate.
Advanced Sync with Multiple Cameras
If you begin using more than one video camera or DSLR/mirrorless in your video productions, syncing sound can suddenly become a bit of a bear! Once you go multi-camera, you should consider getting your cameras on timecode with your audio recorder. To do this, the first step is to have an audio recorder that accepts external timecode devices. Then, you will either need a camera that natively takes timecode, or if you are using DSLR/mirrorless cameras, you need a timecode device per-camera that generates “audio timecode.” Timecode Systems, Denecke, and Tentacle Sync are a few brands that make these devices.
With some professional video cameras, you can append the timecode natively as metadata to the video file via a BNC or Lemo port on the camera. But DSLRs and mirrorless cameras don’t have this capability, so you’ll need to run audio timecode to the camera. You connect a cable from the timecode box to the microphone port on the camera, and it overrides your camera’s audio with a digital signal that sounds a lot like high-pitch turkey gobble (some call this "dweedle"). Then, you use software such as Tentacle Sync Studio to strip the turkey gobble/dweedle tone and append it to the video file’s metadata. It’s a process that doesn’t take too long on the computer, and it is an extra step for the DSLR and Mirrorless users. But still, syncing sound to multiple cameras can be super time-consuming — so once you get on timecode, it is really worth it.
You can see in the photo below, my Canon C100 Mark II has a timecode box plugged into the XLR, feeding audio timecode to the left channel of my camera audio, while the right channel remains free. And on my sound bag at right, the Master timecode devices is sending the Time-of-Day timecode to the camera’s device. You can see I took that picture at right at 10:13am (45 seconds and 06 frames, at 23.976fps).
What this enables you to do is to create a Multi-camera sequence in your editing software and sync it based on the timecode! This automatically lines up your video tracks to the timecode embedded on the audio tracks — immediately syncing all cameras. From there, you can go into multi-camera view and punch the cameras — Camera 1, Camera 2 and so on, speeding up your editing time!
This can be helpful when you are conducting an interview and you have one head-and-shoulders A-Camera view, one close-up B-Camera view, and maybe a third camera on a motorized slider off to the side. Syncing these three with timecode is a real timesaver — and especially important if you have many interviews to conduct over time.
On professional television and movie sets, they will take this a step further and in addition to timecode being sent to camera, they will use a timecode slate that has the timecode read-out on the face of it. If any of the automated functions of syncing via timecode fail, they have a visual at the exact moment of the slate’s "clap" of what the time-code actually is, as it is synced to the audio files. This timecode is read off in Hours: Minutes: Seconds: Frames. So if you are shooting 24 frames per second, it will count up 23 frames and on the 24th, it will count 1 second. After 59 seconds, it will count 1 minute and after 59 minutes it will count 1 hour — all the way up to 24 hours. There are other more complicated aspects to using timecode having to do with the digital equivalents of 24fps — namely, 23.976, which is not exactly 24 frames per second — or how 30 frames per second is actually 29.98fps. But that gets beyond the scope of this lesson and if you begin to jump into that end of the pool, you will be hob-knobbing with location sound professionals.
As you can see in the image below, the 1st Camera Assistant is operating a Terradeck monitor to focus our camera, and the 2nd Camera Assistant (the woman with long hair) is operating the Timecode Slate with the Time-of-Day timecode on display.
There are some considerations when it comes to which microphone style you prefer, how nimble you want to be and what risks are involved if something fails on you in the field. Similar with recorders: How quickly do you want to get up-and-running and be able to navigate the device to a Recording state? And what backups do you want for redundancy in case something fails? How noisy is the room you are conducting your interview? Will your camera time-out after 29 minutes? Will your camera accept XLR inputs or only 1/8th inch (3.5mm)? What is your budget and how many times are you willing to replace that device weighed against how much you will use it?
My recommendation is to get the device with the most fail-safes and backup options, the most user-friendly interface, good battery life and stellar sound to support your quality microphones. Read the reviews, but also qualify who you think is giving the review and if they are scrutinizing the sound as closely as you would.
A beginner set-up could be a DR-10L wired lavalier microphone. Just be aware of the risks you are willing to assume with that set-up.
Once you begin to get paid, you’ll want to consider a boom mic like the Sennheiser MKH-50 along with a quality backup lavalier mic set-up like the Deity Connect feeding into a mixer/recorder.
A beginner recorder could be the Zoom H4N pro, but that could set you up to cry more than once in the future. You might be better off to get a Sound Devices MixPre-3 and use it for many decades. The Zoom F8n is a nice device, but you typically do not need 8 channels for interviews, so that is better suited to situations where there are many microphones or signals in play. The Tascam DR-60 or 70 are decent, but again, not the highest quality and somewhat clunky to work with compared to the F8n or Sound Devices gear.
Remember the signal chain! Start with the highest quality device at the front — that being the microphone! Spend the most on a great microphone and then think about the features of the devices and what is important to you for what you are doing.
- Are the interviews you shoot only at weddings? You may only need a wired lav mic.
- Do you want the redundancy and freedom-of-choice of both lav mic and boom mic? If so, you’ll need a recorder that can handle 2 channels or more.
- Do you want absolute quiet preamps since you are feeding it a quality microphone? It’s a bummer feeding the sound of a $700+ microphone into a noisy device.
- Do you want Dual Channel recording — a.k.a. Attenuated Tracks? Or 32-bit float?
- Do you need Out ports to feed the externally-recorded sound back to camera for a back-up?
- Do you want fast start-up time?
- Do you want an easy-to-navigate interface?
- Do you think you’ll be doing multi-camera shoots where Timecode will really help you? You’ll need a recorder that can accept or supply timecode.
- Will you be broadcasting any sound through speakers at the time of recording, such as a live event videotaping?
- Do you feel that being able to take notes into the metadata of your device will help you organize things in post?
- Do you want to simply record the sound direct to camera to minimize sync in post later?
These are all valid questions that can help you weed out lesser gear and get what you really need.
Thanks for reading! Stay tuned for the 3rd installment of articles in this Sound for Video series: Sound for Wedding Videography!