Five Audio Facts Every Videographer Should Know

When producing video, audio is important. Very important. If you’re just starting out, make sure to spend as much time learning about how to get good audio as you do on video. To that end, I wanted to offer five audio-related facts I think every filmmakers/videographer should know. These aren’t necessarily the most important. There just some key points that are very useful to have tucked away in your brain.

Cable Types. As I mentioned in my “Live Event Filmmaker Survival Guide,” it’s important to have various types of audio cables so that you can handle every occasion. The most common ones you’re most likely to encounter are XLR, quarter-inch and RCA.

XLR connections are the ones most desired by professional filmmakers and videographers. One key reason is because most XLR cables are “balanced.” Without getting too technical, that simply means that the cable is constructed in a way to reduce or eliminate electromagnetic interference. Longer cables are particularly susceptible to such interference. Quarter-inch cables are popular with many DJ or portable audio systems. You’ll recognize RCA cables as the ones connected to your old VCR or game consoles. Rarely have I been in a situation where I needed to use an RCA connection for recording audio.

Microphone Types. You could write an entire blog post on the topic of microphones (scratch that. You could write an entire book). It’s not the scope of this blog post to get into the specifics of each. I just want to make you aware of what’s out there and give you easy access to find out the details.

There are wireless mics and wired mics. There are shotgun mics, lavalier (aka “lav”) mics, handheld and PZM mics. You got your omni-directional (picks up audio from all around the mic), uni-directional (picks up audio from directly in front of the mic), bi-directional (picks up audio from front and back). You got your cardioid, hypercardioid and your supercardioid (cardioid means “heart-shaped” and describes the pick-up pattern of the mic. Handheld mics are usually cardioid. Shotgun mics are typically hyper or supercardioid because they eliminate most of the audio coming from the sides). You got mics with XLR connectors, mics with quarter-inch connectors and mics with mini-jack connectors. You got diversity and non-diversity (the former usually has two antennae and typically have fewer dropouts).

Most of you reading this will be using either wireless lav mics or shotgun mics in your productions. Neither is better than the other. As usual, it all depends on the shoot. If the subject needs a lot of mobility (e.g. documentary, wedding, bar/bat mitzvah, etc.), a wireless lav is probably the best way to go. If you’re shooting interviews with each interviewee sitting or standing in the same location, a good shotgun mic set up is nice because then you don’t have to fuss with taking lav mics on and off each person.

A direct box with two quarter-inch inputs.
A direct box with two quarter-inch inputs.

Line vs. Mic Level. This relates to the power output of an audio signal. Line level signals are significantly stronger than mic level. Line level signals are what’s needed for musical concerts and the like, so they have preamps to boost the signal level. This is important for the videographer because most of your audio recording devices work at mic level. If you try to get a line level feed into a mic, you will get tremendous distortion, unless you have some kind of device like a direct box that can compensate (if you don’t already have a direct box, aka DI box, as part of your audio arsenal, you should get one). Some digital audio recording devices allow you to adjust the recording level down, and that may help.

Bit Depth and Sample Rates. I am NOT an audio expert. (Nor do I play one on TV). So there’s no way I’m going to pretend to know all the ins and outs of the science of audio.  However, as a filmmaker/videographer, you should at least have a modicum of knowledge regarding each.

In short, bit depth is the amount of data recorded in each cycle of audio, which is the sample rate. (And note: it’s bit DEPTH, not RATE. There’s a difference.) Think of bit depth as audio “resolution.” I typically shoot at a 48k/16, that is a 48khz (kilohertz) cycle rate and a 16-bit depth. There is much debate whether it is better to record at 24-bit vs. 16 bit. IMHO, for video (especially if it’s video for the web), you don’t need to significantly increase your audio file size (and required computer processing power) by using a higher bit depth than 16, or a higher sample rate than 48k. That combination has worked fine for me for nearly 11 years.

You Can’t Fix it In Post. If you over or under expose your footage, have too much grain, have terribly shaky camera work, or deal with some other VISUAL hindrance, chances are you can come up with some creative solution to deal with it in post production. (e.g. color grade it a certain way, use b-roll to cover shaky footage, make it black and white if white balance is horrendous, etc.) HOWEVER, if your audio is bad, you are most likely S.O.L. (i.e. in bad shape). There is very little you can do to bad audio to make it sound good. Sure, depending on the issue, sometimes you can add a pass filter here or a compressor filter there to filter out background hum, or boost audio, etc. But 9 times out of 10, you’ll just be stuck with bad audio, which will negatively impact your video. If you have a lot of wind noise because you didn’t use a wind guard, not much you can do. Filming next to a train track with a train noise in the background? Well, you’re stuck with train noise in the background. If you get static interference, or distorted audio from a line level feed going into a mic level receiver with no adjustment, there’s nothing that can fix that. A good photography analogy is shooting in low or medium jpegs and having an image totally blown out. There’s no amount of Photoshopping in the world that create or return information that just isn’t there. Audio is similar. So, do whatever you can to ensure that when you capture audio the first time, you get good, clean audio. I would argue that for once-in-a-lifetime events like weddings, getting good audio is MORE important than getting good video. (Which, by the way, is a great reason for brides to hire a pro vs. Uncle Charlie).

So there you have it. Five facts every filmmaker/videographer should know about audio. Do you have any audio facts and tips you can share? Do so in the comments.

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3 thoughts on “Five Audio Facts Every Videographer Should Know

  1. Reblogged this on 3 Runners Project and commented:
    Just a quick re-blog as I am waiting for The 3 Runners next meeting. I have recently been reading up about audio for film as I am probably going to be on set for all of the filming as an extra pair of hands where ever needed and I want to make myself as useful as possible to the crew. Here is a great blog post by ‘Dare Dreamer Magazine’ about audio.

    All the best,

    Ellen Waghorn – Producer

  2. A little piggie backing…

    George Lucas always emphasized that audio was more important than images in filmmaking. STAR WARS was the first Dolby Surround sound movie released. The first DTS surround sound was Jurassic Park – Speilberg may have directed it, but Lucasfilm and Skywalker Ranch were responsible for the visual effects and the sound! The dinosaurs were nothing without their sound. Ok, now back to Earth for the rest of us filmmakers. lol

    My camera has a switch which allows mic level, line level or phantom power to be used on an XLR plug type cable input. So check your camera for such a switch near your inputs.

    I too have used 48/16 and as it is CD quality (actually slightly better as CDs are 41/16) it’s certainly good enough for speaking voices OR music despite what the vinyl junkies say. lol

    Invest in a couple decent mic stands as they won’t change with evolving electronic equipment. Your $20 mic, $100 mic, $500 mic, $1,000 mic will all be held up with a $30 mic stand. lol Oh and get a boom attachment for one so you can set up for shotgun mic style interviews without having an assistant holding the mic on a boom pole (which you should also have for other applications). I have a couple floor mic stands, table mic stands and one boom attached to a floor mic stand.

    If you shoot weddings, please do yourself a favor and get a uni-directional mic for interviews! AND keep it as clean and “pretty” as possible. Since it will be on-camera AND people will all be dressed up in tuxes and suits and fancy dresses, you don’t want to pull out just any old serviceable mic from your bag. So if there is paint chipping off or the metal screen is dented, it’s time to replace parts, repaint or get a new one and use the beat up mic for things that will be off camera – OR for reliving old David Letterman stunts like rolling things over with a steam roller. lol

    If you shoot dance recitals – make sure to set up a shotgun for capturing taps! You don’t realize how much better your video works when the audio is great and unique.

    In fact, if you are using a mic built into your camcorder to capture sound, you are doing yourself a disservice. For one thing, you probably get all sorts of sounds you don’t know where it comes from. That would be sound of your hands handling your camera. Get a mic that is isolated from your camera for capturing “natural sounds” when shooting. You will always want sound! Even if you don’t use it. You can’t fake sound as well as you can video. Two ways to achieve this is by using a small shotgun mic atop your camera which sits in a mic holder with some kind of isolation buffer – ie rubber rings, rubber banding. OR get a mic holder that fits onto your camera via the shoe atop the camera which can also be “isolated” of vibrations. If you don’t have a mic holder designated spot but you have the shoe atop the camera, you can find many ready made devices which allows you to fit multiple things onto your camera. ie Monitor, Mic, Light etc. Worst case scenario, you don’t have a Pro style camera (I don’t know why not) they even have things that screw into the bottom of your camera to mount mics/monitors/lights etc. Bottom line is AUDIO is possibly more important to capture right the first time than video.

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